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How to stabilize ω-3 polyunsaturated fatty acids (PUFAs) in an animal feeding study? – effects of temperature, oxygen level, antioxidant on oxidative stability of ω-3 PUFAs in a mouse diet
Abstract
Substantial studies have shown that ω-3 polyunsaturated fatty acids (PUFAs) have various health-promoting effects, however, there are inconsistent results from animal studies which showed that ω-3 PUFAs have no effects or even detrimental effects. Emerging research suggests that oxidized ω-3 PUFAs have different effects compared with un-oxidized ω-3 PUFA, therefore, lipid oxidation of dietary ω-3 PUFAs could contribute to the mixed results of ω-3 PUFAs in animal studies. Here we prepared an AIN-93G-based, semi-purified, powder diet, which is one of the most commonly used rodent diets in animal studies, to study the oxidative stability of fortified ω-3 PUFAs in animal feed. We found that lowering the storage temperature or addition of a certain antioxidant, notably tert-butylhydroquinone (TBHQ), helps to stabilize ω-3 PUFAs and suppress ω-3 oxidation in the animal diet while reducing the level of oxygen in storage atmosphere is not very effective. Addition of 50 ppm TBHQ in the diet inhibited 99.5 ± 0.1 % formation of primary oxidation products and inhibited 96.1 ± 0.7 % formation of secondary oxidation products, after 10-day storage of the prepared diet at a typical animal-feeding-experiment condition. Overall, our results highlight that ω-3 PUFAs are highly prone to lipid oxidation in a typical animal feeding experiment, emphasizing the critical importance to stabilize ω-3 PUFAs in animal studies.
... ω-3 PUFAs have the potential to promote health by decreasing risks of inflammation, cardiovascular disorder, and cancer. Previous literature shows that the proportion of lipid oxidation is increased by increasing the concentration of unsaturation and that is why ω-3 PUFAs are extremely susceptible for oxidation due to the presence of double bonds (Zhang et al., 2020). Likewise, PUFAs are most susceptible for oxidation due to their unsaturated bond having nature that generates different metabolites along with reactive oxygen species. ...
... ω-3 PUFAs have the potential to promote health by decreasing risks of inflammation, cardiovascular disorder, and cancer. Previous literature shows that the proportion of lipid oxidation is increased by increasing the concentration of unsaturation and that is why ω-3 PUFAs are extremely susceptible for oxidation due to the presence of double bonds (Zhang et al., 2020). Likewise, PUFAs are most susceptible for oxidation due to their unsaturated bond having nature that generates different metabolites along with reactive oxygen species. ...
Polyunsaturated fatty acids may be derived from a variety of sources and could be incorporated into a balanced diet. They protect against a wide range of illnesses, including cancer osteoarthritis and autoimmune problems. The PUFAs, ω‐6, and ω‐3 fatty acids, which are found in both the marine and terrestrial environments, are given special attention. The primary goal is to evaluate the significant research papers in relation to the human health risks and benefits of ω‐6 and ω‐3 fatty acid dietary resources. This review article highlights the types of fatty acids, factors affecting the stability of polyunsaturated fatty acids, methods used for the mitigation of oxidative stability, health benefits of polyunsaturated fatty acids, and future perspectives in detail. This review article highlights the types of fatty acids, factors affecting the stability of polyunsaturated fatty acids, methods used for the mitigation of oxidative stability, and the health benefits of polyunsaturated fatty acids.
... fish oil, linseed oil or rapeseed oil) in poultry diets is high oxidability (Cholewski, Tomczykowa, and Tomczyk 2018). Therefore, beneficial or detrimental effects of omega-3-rich oils depend on their quality (Zhang et al. 2020). It seems likely that omega-3 PUFA oxidation associated with fishy taste in meat and eggs (Bernardi et al. 2016) restricts their wide usage in poultry industry. ...
Poultry farming is the fastest growing sector of agriculture. Balanced diets are an important factor for realisation of the genetic potential of birds. The pancreas plays an important role in the digestive process. The aim of the review is to describe the adaptation of chicken pancreatic secretory functions to a diet with various protein and fat ingredients. Due to the fact that digestive enzymes correlate with nutrient absorption, basic knowledge of pancreatic secretion can be useful to improve poultry nutrition and the economics of the poultry industry in general. The consumption of soy cake instead of sunflower cake (with a 1.5% increase in dietary crude fat) led to an increase in the activity of pancreatic juice lipase by 33.8%. A slight increase in crude protein in the feed (by 0.5%) led to an increase in proteolytic activity by 28.1% compared to the background period. The consumption of sunflower oil instead of soybean, rapeseed and linseed oil in the diet led to a decrease in the activity of pancreatic juice lipase by 42.2%, 57.6% and 19.1%, respectively. It could be concluded that in chickens there is no strict parallelism in the release of the pancreatic enzymes and there is no clear adaptation to a specific feed component.
... Therefore, there is a need to find a beneficial solution to balance the impact of early weaning in pig farming. One such appropriate solution is to supplement natural antioxidants (e.g., plant essential oil, resveratrol, polyunsaturated fatty acid, mineral) in the feed to attenuate the oxidative stress of weaning piglets, and improve their growth performance (6)(7)(8). ...
Tannic acid (TA) has received widespread attention for its beneficial biological function with antioxidant capacity. This study investigated the protective role of TA on the intestinal antioxidant capacity and intestinal barrier in weaned piglets and porcine intestinal epithelial cells (IPEC-J2). A total of 18 weaned piglets were randomly allocated into two groups (n = 9) and fed with a basal diet (control, CON) and a basal diet containing 1,000 mg/kg TA for two weeks. The in vivo results showed that treatment with TA increased both glutathione peroxidase (GSH-PX) activity and the protein expression of ZO-1 in the jejunum of weaned piglets, and reduced the level of malondialdehyde (MDA) in the serum and the mRNA and protein expression of Keap1 in the jejunum of weaned piglets. Furthermore, in vitro results indicated that TA treatment effectively alleviated tert-butyl hydroperoxide (TBH)-induced oxidative stress in IPEC-J2 cells, improved the antioxidant capacity by elevating the cell redox state and activating the Nrf2 pathway, and improved the intestinal barrier by upregulating the mRNA and protein expression of intestinal tight junction proteins and increasing the transepithelial electrical resistance (TEER) value. In conclusion, these results confirmed that TA relieves oxidative injury and improves intestinal barrier function and intestinal antioxidant capacity by activating the Nrf2 signaling pathway. These findings suggest that TA has the potential application in alleviating oxidative stress in the intestine of weaned piglets.
... These reactions result in enzymatic oxidation with increase the production of Eseries resolvins from EPA, and D-series Resolvins (DHA), prostaglandins, thromboxanes, leukotrienes, epoxy products (84,85). Besides, the ω-3 PUFAs decrease in amount during food confections by thermal processing, while in inversely proportion occurs the increasing of degradation and hazard oxidized substances that damage cell membranes (86,87). The oxidation products are higher in fried, followed by roasted, and boiled foods, which present the same proportion of oxidative products when compared to raw food (88,89). ...
Obesity is associated with the leading causes of death in the worldwide. On the other hand, the intake of vegetables, fruits and fish is related to the reduction of obesity and other metabolic syndromes. This review aims to highlight the role of ingestion of polyphenols and omega-3 polyunsaturated fatty acids (ω-3 PUFAs) in reducing obesity and related metabolic diseases (RMDs). The consumption of vegetables, fish and by-products rich in polyphenols and α-linolenic acid (ALA), as well as oils rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with a decrease in obesity and its RMDs in consumers. Furthermore, we discussed the adequate amount of extracts, powder, polyphenols, ω-3 PUFAs administrated in animal models and human subjects, and the relevant outcomes obtained. Thus, we appeal to the research institutions and departments of the Ministries of Health in each country to develop a food education joint project to help schools, businesses and families with the aim of reducing obesity and other metabolic diseases.
... 2 Bis-allylic positions, and to a lesser extent allylic positions, are prone to react with atmospheric oxygen to form a variety of oxidized compounds including hydroperoxides, epoxides, aldehydes, and acids, which are characterized by bad smell, toxicity, and corrosivity. 3 Besides the obvious deleterious consequences on the organoleptic properties of oils, 4 oxidation processes often lead to the formation of polymeric materials that render handling of waste oils for sustainable production of biofuels a difficult task. 5 From a chemical point of view, lipid peroxidation is a radical-chain reaction sustained by carbon and oxygen-centered radicals, which are responsible for the incorporation of O 2 into organic molecules (Scheme 1A). 6 Antioxidant additives are usually added to reduce the extent of lipid peroxidation in oils. ...
The synergic antioxidant activity of γ-terpinene with α-tocopherol, its synthetic analogue 2,2,5,7,8-pentamethyl-6-chromanol (PMHC), BHT, TBHQ, and catechol was studied by measuring the O2 uptake and the hydroperoxide formation in stripped sunflower oil at 130 °C. Although γ-terpinene was inactive when used alone, it prolonged, in a concentration-dependent manner, the protecting activity of α-tocopherol and of PMHC, while it had no effect on BHT, TBHQ, and catechol. Mechanistic studies performed with alkylnitroxides hydroxy-TEMPO and acetamido-TEMPO, used as molecular probes, suggested that γ-terpinene generates hydroperoxyl (HOO•) radicals, that are responsible for the reduction of the tocopheroxyl radical by a H atom transfer. Experiments on commercial sunflower oil showed that γ-terpinene was able to prolong the induction time due to endogenous tocopherols, demonstrating that this terpene is a promising natural antioxidant for food applications at high temperature.
... For example, in an experimental animal feed, over 65% of oxygen had to be removed before oxidation rates decreased. This is not difficult to accomplish in a low-moisture food because most of the reactive oxygen comes from the atmosphere, and much of it can be removed in less than a minute by nitrogen flushing (Zhang, et al., 2020). However, in food such as oil-in-water emulsions, dissolved oxygen is much more reactive than atmospheric oxygen. ...
Lipid reactions are extremely complex because they involve numerous prooxidants, antioxidants, and lipid substrates whose reactivity is impacted by the physical properties of complex food systems. Understanding the interactions between the factors impacting lipid oxidation reactions is key to developing novel antioxidant strategies. Synergistic antioxidant combinations represent a promising approach to decreasing oxidative rancidity if how and where they work can be better understood.
... 5 However, ω-3 PUFAs were susceptible to oxidation, releasing harmful oxidized products including reactive carbonyl species (RCS, mainly α,βunsaturated aldehydes) and thus leading to the nutritional loss and generation of undesirable rancidity and fishy offflavor. 6,7 The addition of antioxidants including phenolic compounds is one of the major methods employed for controlling lipid oxidation and preserving food quality. The loss of phenolic antioxidants is one issue associated with the oil thermal treatment/storage process. ...
In this research, we studied the antioxidative properties and chemical changes of quercetin in fish oil during accelerated storage at 60 °C for 5 days. Gas chromatography (GC) analysis showed that quercetin inhibited aldehyde formation and unsaturated fatty acid oxidation in fish oil significantly; however, the inhibitory effects decreased gradually with prolonged heating time. Moreover, quercetin was consumed with increasing heating time. Some new phenolic derivatives were discovered in the fish oil with quercetin, with their structures fully elucidated by LC-MS/MS and comparison with newly synthesized ones (characterized by MS and NMR spectroscopy). Based on their chemical structures, we proposed that quercetin reacted with EPA and DHA to form the corresponding quercetin fatty acid esters in fish oil. In addition, the newly formed quercetin-3-O-eicosapentaenoate and quercetin-3-O-docosahexaenoate showed weaker DPPH and ABTS radical cation scavenging activity but much improved lipophilicity, higher cell membrane affinity, and hence enhanced cellular antioxidant activity compared with the parent quercetin. Overall, quercetin could be used as a safe dietary polyphenol to inhibit lipid oxidation. The newly formed quercetin-polyunsaturated fatty acid esters may render improved bioactivity to humans, which needs further investigation.
... 9 The most abundant fatty acids in walnuts were LA with 63.2%, oleic acid (C18:1 n-9) with 14.5%, and αLNA, with 11.2% total fatty acids identified by gas chromatography analysis. 9 Due to the PUFA susceptibility to oxidation when provided as part of the standard animal consumption, 53 we distributed the whole walnut kernels to the experimental animals and strictly followed to ensure every animal ate its portion of the daily walnut amount at the moment of the delivery. ...
Increased dietary, blood, and tissue n-6/n-3 fatty acid ratios are associated with obesity and metabolic syndrome. Due to Westernized dietary patterns, the increasing n-6/n-3 ratio is of growing concern worldwide, and dietary strategies aimed at its lowering are of public health importance. Walnuts are rich in dietary fats, and their consumption promotes cardiometabolic health. This study aimed to examine the effect of 6-week walnut consumption on tissue-specific n-6/n-3 ratio and fatty acid metabolic conversion in fructose-fed rats with a cluster of metabolic disorders. Male Wistar rats were fed a standard diet with or without 10% fructose in drinking water for 9 weeks. Diets of half of the animals were then supplemented with walnuts (2.4 g/day) for 6 weeks, upon which fatty acid profiles were determined in plasma, liver, adipose tissue, and kidney total lipids. Results showed that walnuts induced significant decreases in the n-6/n-3 content of total lipid pool in plasma and examined tissues, irrespective of metabolic burden. Walnut intervention decreased plasma and liver palmitoleic/palmitic, arachidonic/linoleic, and docosahexaenoic/α-linolenic acid ratios. It also modulated individual fatty acid levels by reducing arachidonic and palmitic acid and increasing α-linolenic, eicosapentaenoic, and docosapentaenoic acid in plasma and most tissues. Our study demonstrated that 6-week consumption of walnuts favorably modulated n-6/n-3 plasma and tissue ratio in male Wistar rats regardless of high-fructose feeding, underscoring the promising potential of walnuts in both prevention and treatment of the metabolic syndrome.
The benefits of omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) to human health and the therapeutic properties of diseases have been widely identified. However, due to abundant double bonds, they are sensitive to environmental conditions which cause oxidative deterioration. This is one of the main factors limiting their application. The encapsulation of ω-3 PUFAs is an effective way to improve their oxidation stability. This review summarizes the recent advances in different forms of ω-3 encapsulation systems, such as emulsions, liposomes, microcapsules, and liquid crystalline. Particular emphasis is given to the effects of food-derived biopolymers wall materials (proteins, polysaccharides, and esters) on encapsulation efficiency and oxidation stability of ω-3 PUFAs encapsulation systems. In addition, the effects of natural antioxidants (polyphenols, carotenoids, flavonoids, plant essential oils, etc.) on the antioxidant enhancement of ω-3 PUFAs encapsulation system based on food-derived biopolymers are discussed. Different forms of ω-3 PUFAs encapsulation systems have been proven to be used as supplements in the medical field. The regulation and improvement of the ω-3 PUFAs encapsulation system on the diseases of animal and human, which are related to central nervous system, retina, lung, kidney and tissue cell, are systematically discussed.
Fish and algae oil supplements are enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are precursors to oxidized fatty acids, known as oxylipins. Here, we optimized a base hydrolysis method for measuring oxylipins in oil with UPLC-MS/MS, and quantified them in fish and algae oil supplements. Hydrolysis of 2 µL of oil with sodium carbonate resulted in greater oxylipin concentrations and minimal matrix effects, compared to higher oil volumes (10, 20 and 30 µL). Oxylipin yield was higher when oil was hydrolyzed in methanol containing 0.1% acetic acid and 0.1% butylated-hydroxytoluene, compared to no solvent, and using sodium hydroxide versus sodium carbonate. Oxylipins extracted from 2 µL oil using sodium hydroxide in solvent showed that EPA-derived oxylipins were most abundant in fish oil (84-87%), whereas DHA-oxylipins were abundant in algae oil (83%). This study shows that fish and algae oils are direct sources of EPA- and DHA-derived oxylipins.
Frying in vegetable oil is a popular cooking and food processing method worldwide; as a result, the oils used for frying are widely consumed by the general public and it is of practical importance to better understand their health impacts. To date, the effects of frying oil consumption on human health are inconclusive, making it difficult to establish dietary recommendations or guidelines. Here we show that dietary administration of frying oil, which was prepared under the conditions of good commercial practice, exaggerated dextran sodium sulfate (DSS)-induced colitis and azoxymethane (AOM)/DSS-induced colon tumorigenesis in mice. In addition, dietary administration of frying oil impaired intestinal barrier function, enhanced translocation of lipopolysaccharide (LPS) and bacteria from the gut into the systemic circulation, and increased tissue inflammation. Finally, to explore the potential compounds involved in the actions of the frying oil, we isolated polar compounds from the frying oil and found that administration of the polar compounds exacerbated DSS-induced colitis in mice. Together, our results showed that dietary administration of frying oil exaggerated development of inflammatory bowel disease (IBD) and IBD-associated colon tumorigenesis in mice, and these effects could be mediated by the polar compounds in the frying oil.
The aim of the present study was to evaluate the oxidation status of North American
n
-3 (omega-3) PUFA nutritional supplements commercially available in Canada and evaluate the influence of product formulation and delivery form on oxidative safety. A total of 171 North American over-the-counter
n
-3 PUFA nutritional supplements were analysed for oxidation safety. Primary and secondary oxidation and total oxidation (TOTOX) were determined using the American Oil Chemists’ Society (AOCS) procedures. Comparisons between supplements’ final forms, oil source and
n
-3 PUFA concentration quartiles, as measures of product formulations and delivery forms, were compared using ANOVA. Of the products successfully tested, 50 % exceeded the voluntary recommended levels for markers of oxidation. Another 18 % of products were approaching the limits with 1–3 years before expiration. Encapsulated products without flavour additives had significantly lower secondary and TOTOX levels than bulk oils and flavoured products (
P
< 0·05). Children's products had significantly higher primary, secondary and TOTOX levels compared with all other products (
P
< 0·05). Markers of oxidation did not differ between oil sources (
P
> 0·05), with the exception of krill oil products having higher secondary oxidation levels than plant-based products (
P
> 0·05). Markers of oxidation did not differ between
n
-3 PUFA supplement concentration quartiles. Consumers may be at risk of exposure to higher levels of oxidative products. New regulatory mandates need to be introduced to ensure that all
n
-3 PUFA products, used as nutritional supplements, regardless of their formulation or delivery form, can be tested for oxidative safety and compliance.
Women with evidence of high intake ratios of the marine omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) relative to the omega-6 arachidonic acid have been found to have a reduced risk of breast cancer compared with those with low ratios in some but not all case-control and cohort studies. If increasing EPA and DHA relative to arachidonic acid is effective in reducing breast cancer risk, likely mechanisms include reduction in proinflammatory lipid derivatives, inhibition of nuclear factor-κB-induced cytokine production, and decreased growth factor receptor signaling as a result of alteration in membrane lipid rafts. Primary prevention trials with either risk biomarkers or cancer incidence as endpoints are underway but final results of these trials are currently unavailable. EPA and DHA supplementation is also being explored in an effort to help prevent or alleviate common problems after a breast cancer diagnosis, including cardiac and cognitive dysfunction and chemotherapy-induced peripheral neuropathy. The insulin-sensitizing and anabolic properties of EPA and DHA also suggest supplementation studies to determine whether these omega-3 fatty acids might reduce chemotherapy-associated loss of muscle mass and weight gain. We will briefly review relevant omega-3 fatty acid metabolism, and early investigations in breast cancer prevention and survivorship.
Substantial evidence describes the protective effects of marine-derived omega-3 (n-3) polyunsaturated fatty acids (PUFA) on cardiovascular diseases as well as many other conditions. Numerous fatty acid preparations are marketed for supplementing the Western diet, which is low in n-3 fats. Since these preparations may vary in their n-3 PUFA content, we tested 45 commercially available products on the South African market for their fatty acid composition.
Forty-five commercially available n-3 fatty acid supplements were analysed using gas-liquid chromatography to determine their fatty acid content.
More than half of the n-3 supplements available on the South African market contained ≤ 89% of the claimed content of EPA and/or DHA as stated on the product labels. To meet ISSFAL's recommendation of 500 mg EPA + DHA/day can cost consumers between R2 and R5 per person per day (R60 to R150 p/p/month). Regarding rancidity, the majority of capsules contained conjugated diene (CD) levels higher than that of vegetable oil obtained from opened containers (three months) used for domestic cooking purposes, despite the addition of vitamin E as antioxidant.
Since no formal regulatory structure for dietary supplements currently exists in South Africa, consumers depend on self-regulation within the nutraceutical industry for assurance of product quality, consistency, potency and purity. Our results indicate that more than half of the n-3 fatty acid supplements on the South African market do not contain the claimed EPA and/or DHA contents as stated on product labels, and they contained CD levels higher than that in unused vegetable oils obtained from opened containers used for domestic cooking purposes.
We evaluated the quality and content of fish oil supplements in New Zealand. All encapsulated fish oil supplements marketed in New Zealand were eligible for inclusion. Fatty acid content was measured by gas chromatography. Peroxide values (PV) and anisidine values (AV) were measured, and total oxidation values (Totox) calculated. Only 3 of 32 fish oil supplements contained quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that were equal or higher than labelled content, with most products tested (69%) containing <67%. The vast majority of supplements exceeded recommended levels of oxidation markers. 83% products exceeded the recommended PV levels, 25% exceeded AV thresholds, and 50% exceeded recommended Totox levels. Only 8% met the international recommendations, not exceeding any of these indices. Almost all fish oil supplements available in the New Zealand market contain concentrations of EPA and DHA considerably lower than claimed by labels. Importantly, the majority of supplements tested exceeded the recommended indices of oxidative markers. Surprisingly, best-before date, cost, country of origin, and exclusivity were all poor markers of supplement quality.
Marine derived oils are rich in long-chain polyunsaturated omega-3 fatty acids, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have long been associated with health promoting effects such as reduced plasma lipid levels and anti-inflammatory effects. Krill oil (KO) is a novel marine oil on the market and is also rich in EPA and DHA, but the fatty acids are incorporated mainly into phospholipids (PLs) rather than triacylglycerols (TAG). This study compares the effects of fish oil (FO) and KO on gene regulation that influences plasma and liver lipids in a high fat diet mouse model.
Male C57BL/6J mice were fed either a high-fat diet (HF) containing 24% (wt/wt) fat (21.3% lard and 2.3% soy oil), or the HF diet supplemented with FO (15.7% lard, 2.3% soy oil and 5.8% FO) or KO (15.6% lard, 2.3% soy oil and 5.7% KO) for 6 weeks. Total levels of cholesterol, TAG, PLs, and fatty acid composition were measured in plasma and liver. Gene regulation was investigated using quantitative PCR in liver and intestinal epithelium.
Plasma cholesterol (esterified and unesterified), TAG and PLs were significantly decreased with FO. Analysis of the plasma lipoprotein particles indicated that the lipid lowering effect by FO is at least in part due to decreased very low density lipoprotein (VLDL) content in plasma with subsequent liver lipid accumulation. KO lowered plasma non-esterified fatty acids (NEFA) with a minor effect on fatty acid accumulation in the liver. In spite of a lower omega-3 fatty acid content in the KO supplemented diet, plasma and liver PLs omega-3 levels were similar in the two groups, indicating a higher bioavailability of omega-3 fatty acids from KO. KO more efficiently decreased arachidonic acid and its elongation/desaturation products in plasma and liver. FO mainly increased the expression of several genes involved in fatty acid metabolism, while KO specifically decreased the expression of genes involved in the early steps of isoprenoid/cholesterol and lipid synthesis.
The data show that both FO and KO promote lowering of plasma lipids and regulate lipid homeostasis, but with different efficiency and partially via different mechanisms.
Lipid oxidation products can arise when oils are subjected to high temperature and exposed to oxygen. Many of these oxidation products have higher polarity than the original triacylglycerols due to the incorporation of oxygen. These polar oxidation products could have a negative impact on oxidative stability by acting as prooxidants. In this study, the influence of polar lipid oxidation products on the oxidative stability of bulk oils and oil-in-water emulsions was investigated. Polar compounds were isolated from used frying oil by silica gel column chromatography. They were added to bulk stripped corn oil (with/without reverse micelles formed by dioleoylphosphatidylcholine, DOPC) and oil-in-water (O/W) emulsion to evaluate their prooxidative activity. Polar compounds increased lipid oxidation in bulk oil with and without DOPC. The presence of DOPC reverse micelles decreased the prooxidant activity of the polar oxidation products. On the other hand, there was no significant effect of the polar compounds on oxidation of O/W emulsions. To gain a better understanding of the polar compounds responsible for the prooxidant effect, linoleic acid and linoleic hydroperoxide were added into bulk oil at the same concentration as those in the polar fraction of the frying oil. However, they did not show the same prooxidative activity compared to oil with the polar fraction.
Abstract The oxidation level of omega-3 fatty acid supplements commercialized in capsules may be a risk to consumers' health. For this purpose, we have designed a single-blind, parallel-group, randomized controlled trial in which 52 women participated. Volunteers were randomly distributed into three groups consuming: (1) less oxidized oil pills, (2) highly oxidized oil pills and (3) no capsules. All groups consumed a fish-rich diet. Circulating glucose, total cholesterol, triglycerides and glutamic pyruvic transaminase were determined at the beginning and end (30 days) of the study. As a result, the ingestion of less oxidized ω-3 supplements reduced circulating triglyceride and cholesterol levels, as opposed to the highly oxidized omega-3 capsules, which had a negative effect on cholesterol levels. In conclusion, the level of oxidation of the supplements is a key factor in controlling circulating lipid profile. Therefore, manufacturers must pay attention to the quality of the prime product prior to encapsulation.
Marine omega-3 rich oils are used by more than a third of American adults for a wide range of purported benefits including prevention of cardiovascular disease. These oils are highly prone to oxidation to lipid peroxides and other secondary oxidation products. Oxidized oils may have altered biological activity making them ineffective or harmful, though there is also evidence that some beneficial effects of marine oils could be mediated through lipid peroxides. To date, human clinical trials have not reported the oxidative status of the trial oil. This makes it impossible to understand the importance of oxidation to efficacy or harm. However, animal studies show that oxidized lipid products can cause harm. Oxidation of trial oils may be responsible for the conflicting omega-3 trial literature, including the prevention of cardiovascular disease. The oxidative state of an oil can be simply determined by the peroxide value and anisidine value assays. We recommend that all clinical trials investigating omega-3 harms or benefits report the results of these assays; this will enable better understanding of the benefits and harms of omega-3 and the clinical importance of oxidized supplements.
The aim of this study was to examine omega-3 LC PUFA content and oxidative stability of fish oil dietary supplements available in Poland. Nineteen brands of fish body oil and fish liver oil capsules were purchased over the counter and analyzed. Oil content, fatty acid composition and peroxide value were determined. The label claims for EPA and DHA for the majority of the products were presented with reasonable accuracy. However, it can be supposed that the oxidative stability of some fish oil products available on the market might not be sufficient to ensure health quality and safety during longer storage.
Dietary intake of long-chain n-3 PUFA is now widely advised for public health and in medical practice. However, PUFA are highly prone to oxidation, producing potentially deleterious 4-hydroxy-2-alkenals. Even so, the impact of consuming oxidized n-3 PUFA on metabolic oxidative stress and inflammation is poorly described. We therefore studied such effects and hypothesized the involvement of the intestinal absorption of 4-hydroxy-2-hexenal (4-HHE), an oxidized n-3 PUFA end-product. In vivo, four groups of mice were fed for 8 weeks high-fat diets containing moderately oxidized or unoxidized n-3 PUFA. Other mice were orally administered 4-HHE and euthanized postprandially versus baseline mice. In vitro, human intestinal Caco-2/TC7 cells were incubated with 4-hydroxy-2-alkenals. Oxidized diets increased 4-HHE plasma levels in mice (up to 5-fold, P < 0.01) compared with unoxidized diets. Oxidized diets enhanced plasma inflammatory markers and activation of nuclear factor kappaB (NF-κB) in the small intestine along with decreasing Paneth cell number (up to -19% in the duodenum). Both in vivo and in vitro, intestinal absorption of 4-HHE was associated with formation of 4-HHE-protein adducts and increased expression of glutathione peroxidase 2 (GPx2) and glucose-regulated protein 78 (GRP78). Consumption of oxidized n-3 PUFA results in 4-HHE accumulation in blood after its intestinal absorption and triggers oxidative stress and inflammation in the upper intestine.
Marine-derived n-3 (omega-3) PUFAs may reduce risk of developing colorectal cancer; however, few studies have investigated the association of n-3 PUFA intakes on colorectal polyp risk.
The objective of this study was to examine the associations of dietary PUFA intake on risk of colorectal adenomatous and hyperplastic polyps.
This was a colonoscopy-based case-control study that included 3166 polyp-free control subjects, 1597 adenomatous polyp cases, and 544 hyperplastic polyp cases. Dietary PUFA intake was calculated from food-frequency questionnaires and tested for association by using unconditional logistic regression. The urinary prostaglandin E(2) metabolite, which is a biomarker of prostaglandin E(2) production, was measured in 896 participants by using liquid chromatography and tandem mass spectrometry.
n-6 PUFAs were not associated with adenomatous or hyperplastic polyps in either men or women. Marine-derived n-3 PUFAs were associated with reduced risk of colorectal adenomas in women only, with an adjusted OR of 0.67 (95% CI: 0.47, 0.97) for the highest quintile of intake compared with the lowest quintile of intake (P-trend = 0.01). Dietary intake of α-linolenic acid was associated with an increased risk of hyperplastic polyps in men (P-trend = 0.03), which was not seen in women. In women, but not in men, dietary intake of marine-derived n-3 PUFAs was negatively correlated with urinary prostaglandin E(2) production (r = -0.18; P = 0.002).
Higher intakes of marine-derived n-3 PUFAs are associated with lower risk of adenomatous polyps in women, and the association may be mediated in part through a reduction in the production of prostaglandin E(2). This trial was registered at clinicaltrials.gov as NCT00625066.
Omega (ω)-3 polyunsaturated fatty acids (PUFAs) are naturally occurring substances that are well tolerated and have been used extensively for the prevention of cardiovascular disease. More recently, ω-3 PUFAs have been recognised to have anticancer activity. There is also evidence suggesting improved efficacy and/or tolerability of conventional cancer chemotherapy when administered with ω-3 PUFAs. The purpose of this review is to (i) describe the mechanisms by which ω-3 PUFAs are thought to have antineoplastic activity, (ii) review published preclinical and clinical studies that support anti-colorectal cancer activity and (iii) summarise current clinical trials investigating the potential therapeutic role(s) of ω-3 PUFAs at different stages of colorectal carcinogenesis, from adenoma (polyp) prevention to treatment of established malignant disease and prevention of cancer recurrence.
For sixteen years, the American institute of Nutrition Rodent Diets, AIN-76 and AIN-76A, have been used extensively around the world. Because of numerous nutritional and technical problems encountered with the diet during this period, it was revised. Two new formulations were derived: AIN-93G for growth, pregnancy and lactation, and AIN-93M for adult maintenance. Some major differences in the new formulation of AIN-93G compared with AIN-76A are as follows: 7 g soybean oil/100 g diet was substituted for 5 g corn oil/ 100 g diet to increase the amount of linolenic acid; cornstarch was substituted for sucrose; the amount of phosphorus was reduced to help eliminate the problem of kidney calcification in female rats; L-cystine was substituted for DL-methionine as the amino acid supplement for casein, known to be deficient in the sulfur amino acids; manganese concentration was lowered to one-fifth the amount in the old diet; the amounts of vitamin E, vitamin K and vitamin B-12 were increased; and molybdenum, silicon, fluoride, nickel, boron, lithium and vanadium were added to the mineral mix. For the AIN-93M maintenance diet, the amount of fat was lowered to 40 g/kg diet from 70 g/kg diet, and the amount of casein to 140 g/kg from 200 g/kg in the AIN-93G diet. Because of a better balance of essential nutrients, the AIN-93 diets may prove to be a better choice than AIN-76A for long-term as well as short-term studies with laboratory rodents.
Animal and in vitrostudies support a role for polyunsaturated fatty acids (PUFAs) in colon carcinogenesis; however, the epidemiological evidence is inconclusive. Recently, we investigated their role within the Singapore Chinese Health Study, a population-based cohort of Singapore Chinese men and women. We reported that a high intake of marine n-3 PUFAs was associated with an increased risk of colorectal cancer (CRC). Oxidation of PUFAs incorporated into cell membranes generates lipid hydroperoxides, which can be mutagenic. In this report, we investigated whether single nucleotide polymorphisms (SNPs) in DNA repair genes modified the effect of PUFAs on CRC risk using a nested case-control study within the Singapore Chinese Health Study. We genotyped 1,181 controls and 311 cases (180 colon and 131 rectal cancer) for SNPs in the XRCC1 (Arg194Trp, Arg399Gln), OGG1 (Ser326Cys), PARP (Val762Ala, Lys940Arg), and XPD (Asp312Asn, Lys751Gln) genes. We observed that the PARP Val762Ala SNP modified the association between marine n-3 PUFA and rectal cancer risk, with no evidence of interaction among colon cancer (heterogeneity test p=0.003). Our results suggest a positive association between high intake of marine n-3 PUFA and rectal cancer risk among carriers of at least one PARP codon 762 Ala allele (odds ratio=1.7, 95% confidence interval=1.1-2.7).
Long-chain ω-3 polyunsaturated fatty acids (PUFAs) may have antineoplastic properties in the colon. The authors examined the
association between intakes of different PUFAs and distal large bowel cancer in a population-based case-control study of 1,503
whites (716 cases; 787 controls) and 369 African Americans (213 cases; 156 controls) in North Carolina (2001–2006). Unconditional
logistic regression was used to estimate odds ratios and 95% confidence intervals for distal large bowel cancer risk in relation
to quartiles of PUFA intake. Increased consumption of long-chain ω-3 PUFAs was associated with reduced risk of distal large
bowel cancer in whites (multivariable odds ratios = 0.88 (95% confidence interval (CI): 0.63, 1.22), 0.69 (95% CI: 0.49, 0.98),
and 0.49 (95% CI: 0.34, 0.71) for second, third, and highest vs. lowest quartile) (Ptrend < 0.01). Intake of individual eicosapentaenoic acids and docosahexaenoic acids was inversely related to distal large bowel
cancer risk, whereas the ratio of ω-6 to long-chain ω-3 PUFAs was associated with increased risk of distal large bowel cancer
in whites, but not among African Americans (Pinteraction < 0.05). Study results support the hypothesis that long-chain ω-3 PUFAs have beneficial effects in colorectal carcinogenesis.
Whether or not the possible benefit of long-chain ω-3 PUFAs varies by race warrants further evaluation.
The potential therapeutic benefits of supplementation with n-3 polyunsaturated fatty acids (PUFAs) in various diseases are reviewed, and the antiinflammatory actions, activity, and potential drug interactions and adverse effects of n-3 PUFAs are discussed.
Fish oils are an excellent source of long-chain n-3 PUFAs, such as eicosapentaenoic acid and docosahexaenoic acid. After consumption, n-3 PUFAs can be incorporated into cell membranes and reduce the amount of arachidonic acid available for the synthesis of proinflammatory eicosanoids (e.g., prostaglandins, leukotrienes). Likewise, n-3 PUFAs can also reduce the production of inflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1, and interleukin-6. Considerable research has been conducted to evaluate the potential therapeutic effects of fish oils in numerous conditions, including arthritis, coronary artery disease, inflammatory bowel disease, asthma, and sepsis, all of which have inflammation as a key component of their pathology. Additional investigations into the use of supplementation with fish oils in patients with neural injury, cancer, ocular diseases, and critical illness have recently been conducted. The most commonly reported adverse effects of fish oil supplements are a fishy aftertaste and gastrointestinal upset. When recommending an n-3 PUFA, clinicians should be aware of any possible adverse effect or drug interaction that, although not necessarily clinically significant, may occur, especially for patients who may be susceptible to increased bleeding (e.g., patients taking warfarin).
The n-3 PUFAs have been shown to be efficacious in treating and preventing various diseases. The wide variation in dosages and formulations used in studies makes it difficult to recommend dosages for specific treatment goals.
The official International Dairy Federation method for determination of the peroxide value of anhydrous milk fat was extended to poultry, meat, fish, and vegetable oils. The ferrous oxidation-xylenol orange method for determination of peroxide values of liposomes and lipoproteins was modified to make it simpler and more rapid. These 2 spectrophotometric methods were used successfully to determine the peroxide values of beef, chicken, butter, fish, and vegetable products. The results in most cases were consistent with those obtained by using the AOAC Official Method. The spectrophotometric methods have an assay time of less than 10 min, require < or = 0.3 g fat, and are capable of determining peroxide values as low as 0.1 mequiv/kg of sample.
The inhibitory effect of n-3 polyunsaturated fatty acids on human colorectal cancer has been speculated on from epidemiological
data and animal studies. We conducted a long-term trial of docosahexanoic acid (DHA)-concentrated fish oil capsules for patients
in a high-risk group for colorectal cancer. During this trial, we experienced three patients with familial adenomatous polyposis
(FAP) diagnosed as having malignant lesions. Three patients with FAP and two patients with multiple (more than 30) colorectal
polyps were administered DHA-concentrated fish oil capsules _Hlk427554600[2.2 g of DHA and 0.6 g of eicosapentanoic acid (EPA)
per day] for one or two years. Compliance with DHA-concentrated fish oil capsules was more than 90% in four patients and 61
% in one patient. A marked increase or decrease in the number of polyps was not observed. Three patients with FAP developed
endometrial cancer after 12 months, colon cancer after 24 months and lung cancer after 12 months, respectively. All cancers
were diagnosed at an early stage and were resected curatively. We thought that the possibility of developing cancer from the
long-term administration of fish oil capsules to patients with FAP needs to be investigated further, and that we should report
these cases.
Dietary recommendations have been made for n-3 fatty acids, including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) to achieve nutrient adequacy and to prevent and treat cardiovascular disease. These recommendations are based on a large body of evidence from epidemiologic and controlled clinical studies. The n-3 fatty acid recommendation to achieve nutritional adequacy, defined as the amount necessary to prevent deficiency symptoms, is 0.6-1.2% of energy for ALA; up to 10% of this can be provided by EPA or DHA. To achieve recommended ALA intakes, food sources including flaxseed and flaxseed oil, walnuts and walnut oil, and canola oil are recommended. The evidence base supports a dietary recommendation of approximately 500 mg/d of EPA and DHA for cardiovascular disease risk reduction. For treatment of existing cardiovascular disease, 1 g/d is recommended. These recommendations have been embraced by many health agencies worldwide. A dietary strategy for achieving the 500-mg/d recommendation is to consume 2 fish meals per week (preferably fatty fish). Foods enriched with EPA and DHA or fish oil supplements are a suitable alternate to achieve recommended intakes and may be necessary to achieve intakes of 1 g/d.
Fish is the main dietary source of long-chain n-3 fatty acids, which have been suggested to play a protective role in colorectal cancer development in laboratory and animal studies. Human studies have not shown consistent results. We examined the association between intakes of fish and n-3 fatty acids from fish and colorectal cancer risk in men enrolled in the Physicians' Health Study.
The Physicians' Health Study began as a randomized trial to examine the effect of aspirin and beta-carotene supplementation on cancer and cardiovascular disease. Fish intake was assessed at the 12-month follow-up with an abbreviated food-frequency questionnaire. Cox proportional hazards models were used to estimate multivariate relative risks for colorectal cancer for the categories of fish intake and quartiles of n-3 fatty acid intake.
During 22 years of follow-up, 500 men had a confirmed diagnosis of colorectal cancer. Fish intake was inversely associated with colorectal cancer risk [multivariate relative risk (95% confidence interval) for highest versus lowest category, 0.63 (0.42-0.95); P trend = 0.02] [corrected] The inverse association was observed for both colon and rectal cancers. Our findings for n-3 fatty acids were similar to those for fish; the multivariate relative risk (95% confidence interval) of total colorectal cancer for the highest versus lowest quartile of n-3 fatty acids was 0.74 (0.57-0.95; P trend = 0.01).
Our results from this long-term prospective study suggest that intakes of fish and long-chain n-3 fatty acids from fish may decrease the risk for colorectal cancer.
In this study, base algae oil was gelled through the formation of crystal network using food grade monoacylglycerol (MAG). The impact of MAG concentration (5, 10, 20 wt%) and water content (0, 5 wt %) on physical properties and oxidative stability of gelled algae oil was systematically investigated. The antioxidative activity of 300 μM hydrophilic antioxidant, i.e., ascorbic acid and green tea extract, on oxidative stability of gelled algae oil by 20 wt% of MAG was also examined. The results obtained clearly showed that melting temperature, melting of entropy and complex modulus of algae oil increased with increasing MAG concentration. The addition of 5 wt% water can negatively affect the strength of MAG crystal network and physically stable gel system can only be formed with 20 wt% MAG. The stronger crystal network formed by 20 wt % MAG retarded lipid oxidation of algae oil due to the creation of a physical barrier to restrain the attack from oxygen. The addition of green tea extract could further synergize with MAG crystalline network by form a thermodynamic barrier to effectively quench the radicals, thus prolonging the oxidative stability of algae oil 4-fold longer than base algae oil.
The ω-3 polyunsaturated fatty acids (PUFAs) are among the most popular dietary supplements in the US, but they are chemically unstable and highly prone to lipid peroxidation. Many studies performed in different countries demonstrate that the majority of ω-3 PUFA products on the market are oxidized, suggesting that the resulting ω-3 PUFA peroxidation-derived compounds could be widely consumed by the general public. Therefore, it is of practical importance to understand the effects of these oxidized lipid compounds on human health. In this review, we summarize and discuss the chemical structures and biological activities of ω-3 PUFA peroxidation-derived compounds, and emphasize the importance to better understand the role of lipid peroxidation in biological activities of ω-3 PUFAs.
The impact of 0, 40, 58, 79, 93, and 98% total oxygen reduction on lipid oxidation kinetics in a 1.0% fish oil‐in‐water emulsion (pH 3.0; 32°C) was determined. Atmospheres were modified using nitrogen/oxygen gas blends or high purity nitrogen. Headspace and dissolved oxygen were monitored throughout the study using a non‐destructive technique in which fluorescent sensors were fixed in sealed vials. Lipid oxidation, as measured by lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS), was inhibited at oxygen reductions ≥58%. However, meaningful protection against lipid oxidation was only achieved at oxygen reductions ≥93%. Potential commercial strategies, nitrogen flushing/sparging, and ascorbic acid, were inefficient at reducing oxygen to levels that could significantly inhibit lipid oxidation. Results suggest that near complete oxygen removal is necessary to protect oxygen‐sensitive ingredients, but a need still exists to identify new strategies that sufficiently reduce the oxygen content of emulsions.
Practical applications: The practical application of this work is that there is a global demand to remove synthetic additives from food and beverage formulations, and as described in this work, defining the level oxygen reduction that provides meaningful increases in oxidative stability is necessary. Results suggest that the oxidative stability of 1% fish oil‐in‐water emulsions can be extended by reducing system oxygen by ∼58%, but to have a meaningful antioxidant impact greater than ∼93% oxygen removal is required. Further investigation into simulated commercial oxygen removal strategies (e.g., nitrogen displacement of oxygen and ascorbic acid) demonstrated that current industrial strategies are lacking and need to be optimized in order to enhance stability against lipid oxidation.
In this work, we design and modify a fish oil‐in‐water emulsion system to have different oxygen concentrations that range from almost complete oxygen removal to atmospheric conditions. The resulting emulsions are characterized over time by non‐destructively measuring oxygen concentrations, both in the headspace and dissolved phase, as shown in the figure of two sensor patches inside a sealed glass vial. The impact of oxygen concentrations on lipid oxidation kinetics is measured and represented in the graphed data. Results suggest that near complete oxygen removal is necessary to provide meaningful protection against lipid oxidation in emulsified systems.
Fish oil nanoemulsions, stabilized with different mixtures of non-ionic surfactants (Tween 80, Span 80), were prepared by high intensity ultrasound method. Physicochemical properties and storage stability of nanoemulsions were studied under the effects of surfactant to oil ratio (SOR 0.5–1.5), hydrophilic lipophilic balance (HLB 9–15) and temperature (4 and 25 °C) for 1 month. Nanoemulsions of an average droplet size of 82 nm were obtained after sonication for 10 min. An increase in SOR and HLB led to a decrease in particle size and optical density. Conventional emulsions were more oxidatively stable than respective nanoemulsions. Ostwald ripening rate and oxidative instability of nanoemulsions stored at 25 °C were lower than those measured at 4 °C. Increased oxidative stability at higher temperatures was attributed to the decreased solubility of oxygen at higher temperatures as well as to the possible differences in the molecular orientations of the fatty acids within the droplets at different temperatures. Ostwald ripening was the major destabilizing mechanism during storage of nanoemulsions at low temperature and in the early stage of nanoemulsion storage at higher temperature. After 2 weeks, other mechanisms such as flocculation and coalescence revealed more important roles. Incorporating α-tocopherol into nanoemulsions fairly increased the chemical stability of unsaturated fatty acids maybe because of its partitioning mainly at the interface. However, after two weeks it was not so efficient. Morphological studies confirmed the results obtained by laser diffraction technique.
Storage stability of cooked meat sausages with 50g marine oil/kg and two salt combinations: (1) 14.00g NaCl/kg and 2.0g sodium tripolyphosphate (TPP)/kg, (2) sodium reduced formulation with 6.08g NaCl/kg, 4.92g KCl/kg and 5.00g TPP/kg were studied. In addition, effect of BHA or tocopherols as antioxidants was tested. Changes in process yield, purge loss, texture, color, microbial growth and pH during vacuum refrigerated storage were monitored. Partial substitution of sodium did not affect matrix stability, maintaining high process yields and low purge losses (≤5.5%). The products with marine oil used as fat source resulted in: high PUFA levels and lower risks indicators associated with cardiovascular events. Tocopherols prevented the oxidation process; n-6/n-3 ratio remained unchanged throughout the storage, establishing a natural alternative to BHA. Moreover, the consumption of 15-18g of this product would cover the recommended daily intake of EPA+DHA. Practical Applications: In previous works, we developed formulations replacing the beef fat with preemulsified and deodorized marine oil. We also study an alternative formulation with low sodium content. These characteristics are a necessity for the consumers who are demanding better nutritional quality products, and the producers must attend that demand. Other authors have studied different low fat and/or low sodium meat systems or meat emulsions with different fat sources to enhance the nutritional quality. Nevertheless there is not much knowledge of the stability of these new meat systems, containing more water, and more PUFA. Thus, the aim of this research was to study the storage stability of different cooked meat sausages with fish oil from different approaches (microbial, physicochemical and oxidative). Assuring the stability of these products is essential to the producers to maximize the shelf-life.
The aim of the present study was to evaluate the oxidation status of North American n-3 (omega-3) PUFA nutritional supplements commercially available in Canada and evaluate the influence of product formulation and delivery form on oxidative safety. A total of 171 North American over-the-counter n-3 PUFA nutritional supplements were analysed for oxidation safety. Primary and secondary oxidation and total oxidation (TOTOX) were determined using the American Oil Chemists' Society (AOCS) procedures. Comparisons between supplements' final forms, oil source and n-3 PUFA concentration quartiles, as measures of product formulations and delivery forms, were compared using ANOVA. Of the products successfully tested, 50 % exceeded the voluntary recommended levels for markers of oxidation. Another 18 % of products were approaching the limits with 1–3 years before expiration. Encapsulated products without flavour additives had significantly lower secondary and TOTOX levels than bulk oils and flavoured products (P < 0·05). Children's products had significantly higher primary, secondary and TOTOX levels compared with all other products (P < 0·05). Markers of oxidation did not differ between oil sources (P > 0·05), with the exception of krill oil products having higher secondary oxidation levels than plant-based products (P > 0·05). Markers of oxidation did not differ between n-3 PUFA supplement concentration quartiles. Consumers may be at risk of exposure to higher levels of oxidative products. New regulatory mandates need to be introduced to ensure that all n-3 PUFA products, used as nutritional supplements, regardless of their formulation or delivery form, can be tested for oxidative safety and compliance.
The polarity and partitioning of antioxidants (AOX) in lipid dispersions and bulk oils has a large impact on efficacy, but this has not yet been studied in low-moisture foods. Using a homologous series of rosmarinic esters as AOX in crackers, we determined that efficacy increases with increasing hydrophobicity based on lipid hydroperoxide and hexanal generation. Confocal microscopy was used to determine location of both lipids and AOX. Hydrophobic rosmarinic esters partitioned more closely with the lipid than rosmarinic acid, presumably placing the hydrophobic AOX at the site of oxidation reactions. Partitioning and efficacy of the intermediate polarity ester was affected by mode of incorporation (e.g. added to the water or to the lipid prior to dough formation). The synthetic AOXs propyl gallate, butylhydroxy toluene, and tert-butylhydroquinone gave similar results with the more hydrophobic BHT and TBHQ being more effective at reducing lipid hydroperoxide and hexanal generation than the more hydrophilic propyl gallate. These results provide important information on which AOX would be most effective in low-moisture foods.
The polychlorinated aromatic antimicrobials triclosan
and triclocarban are in widespread use for killing microorganisms
indiscriminately, rapidly, and by nonspecific action. While their
utility in healthcare settings is undisputed, benefits to users of
antimicrobial personal care products are few to none. Yet, these latter,
high-volume uses have caused widespread contamination of the environment,
wildlife, and human populations. This feature article presents a timeline
of scientific evidence and regulatory actions in the U.S. concerning
persistent polychlorinated biocides, showing a potential path forward
to judicious and sustainable uses of synthetic antimicrobials, including
the design of greener and safer next-generation alternatives.
Encapsulated fish oils are extensively commercialized in Brazil. These products could have an effect in the reduction of heart
diseases because of their high content of polyunsaturated fatty acids. However, information about their composition and quality
are still lacking. Fatty acid composition, oxidative stability (Rancimat, 80C, 2.5 g sample and 8.3 L/h air), peroxide value
(PV), and polar compound content were determined in sixteen trademarked encapsulated fish and cod-liver oils, purchased from
Brazilian markets. The highly polyunsaturated fatty acid (eicosapentaenoic acid+docosahexaenoic acid) level appear to be typical
of marine oils (16.2 and 32.1%). The PV ranged from 2.1 to 20.3 meq/kg, which is considered high, whereas the Rancimat induction
periods varied from 1.95 to 8.45 h. The samples analyzed contained from 0.1 to 8.3% polar components. In some cases, both
composition and quality were inadequate for this kind of product. One of the samples did not contain cod-liver oil, it appears
that it contained soybean oil.
We evaluated the efficacy of fish oil n-3-[omega]-fatty acids, inhibitors of leukotriene synthesis, in the treatment of ulcerative colitis. An open trial of 10 patients with mild to moderate ulcerative colitis who had either failed (n = 9) or refused (n = 1) conventional therapy was performed. Patients received 15 MAX-EPA capsules containing a total of 2.7 g of eicosapentanoic acid in three divided doses daily for 8 weeks. The activity of ulcerative colitis and response to therapy was based upon daily stool diaries, sigmoidoscopy, and symptomatic response. All patients tolerated the fish oil and showed no alteration in routine blood studies. Seven patients had moderate to marked improvement; steroid dose could be reduced in four of the five patients on prednisone. Three patients had little or no improvement. No patient worsened. These results of our open study appear to justify a double-blind trial of this dietary supplement in ambulatory patients with ulcerative colitis.
ScopeThis study investigated the effects of supplementing different ratios of omega-6 and omega-3 fatty acids (O6H = 10:1, O3O6 = 4:1, and O3H = 1:4) to western-style diets on cow -lactoglobulin (BLG) induced allergic reactions in Balb/c mice. Methods and resultsThree-week-old mice were randomly assigned to three diet groups (n = 20/group). At 9 wk of age, half of the mice from each dietary treatment (n = 10) were intraperitoneally (i.p.) sensitized with three weekly doses of BLG and alum while the remaining half from each group was sham sensitized (controls). One week after the final sensitization, all mice were orally challenged with BLG. Elevated BLG-specific serum Igs were observed in all sensitized and challenged mice. IFN-, MCP-1, and IL-12p40 concentrations from lymphocytes of mesenteric lymph nodes were highest in O3H mice, compared to O3O6 and O6H mice. O6H mice had the highest IL-4 concentrations from splenic lymphocytes and a significantly lower rectal temperature after the challenge in comparison to O3O6 and O3H mice. Conclusions
Our results suggest that the -3 PUFA rich diets alleviated the severity of allergic reactions, and may modulate immune response toward T helper cell (Th)1-favoured immune response while the -6 PUFA rich diet exhibited no allergy alleviation with a stronger Th2 polarized immune response.
Background:
Fish oil supplements have grown in popularity in recent years owing to their multiple health benefits, leading to rapid growth in the number of fish oil supplements available for consumers. When choosing a product, it is important that label claims for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are met, especially when a specific dosage is required. In this study the amounts of EPA and DHA in 16 of the top-selling liquid fish oil products from the American marketplace were analysed and compared with their label claims. Peroxide value, a measure of oxidation, was also determined, along with lipid class.
Results:
This study found that over half of the supplements did not meet their label claims for EPA and DHA, and a quarter exceeded recommended limits for peroxide value.
Conclusion:
These results suggest that more stringent regulation is required for fish oil products.
The effect of tertiarybutylhydroquinone (TBHQ) in retarding lipid oxidation in fish crackers fried in refined, bleached and deodorised palm olein (RBD olein) during storage was evaluated. The indices of lipid oxidation used were the peroxide and p-anisidine values and u.v. absorbances at 232 and 268 nm of oil extracted from fish crackers stored at 60°C. Two methods for TBHQ incorporation into the fish crackers were used. Fish crackers that were prepared by frying of fish chips in RBD olein containing TBHQ were more stable towards oxidative rancidity than control fish crackers prepared with RBD olein without TBHQ. The rate of lipid oxidation in fish crackers prepared from fish chips that were made with TBHQ in the dough formulation and fried in RBD olein without TBHQ was slightly higher than in control fish crackers. A storage study carried out at room temperature (30°C) showed the same trend in relative rates of lipid oxidation. The study showed that the incorporation of TBHQ into the frying medium was an effective means of retarding the onset of rancidity in fried fish crackers while the incorporation of TBHQ into the dough mixture made the fish cracker slightly more susceptible towards lipid oxidative reactions.
Several human and animal studies have shown that n-3 polyunsaturated fatty acids (PUFA) might be associated with a decreased risk, whereas other studies showed that n-6 PUFA may be associated with an increased risk of colorectal cancer. However, results from these studies are not consistent. We evaluated the associations between serum n-3 and n-6 PUFA levels and colorectal adenoma risk in an endoscopy-based case–control study, conducted in The Netherlands between 1997 and 2002. We included 363 cases of colorectal adenomas and 498 adenoma-free controls. Serum fatty acids were measured in cholesteryl esters. Logistic regression models were used to calculate odds ratios (OR), which were adjusted for age, gender and alcohol intake. Total serum n-3 PUFA levels were inversely associated with colorectal adenoma risk, the OR comparing the third tertile with the first tertile was 0.67 [95% confidence interval (CI) 0.46–0.96, p for trend = 0.03]. Serum eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) and the n-3/n-6 ratio were inversely associated with colorectal adenoma risk, but these were not statistically significant. In contrast, the risk of colorectal adenomas was increased by total n-6 PUFA with an OR of 1.68 (95% CI, 1.17–2.42, p for trend = 0.006) and by linoleic acid (LA; C18:2n-6) with an OR of 1.65 (95% CI, 1.15–2.38, p for trend = 0.007). This is the first observational study that simultaneously finds an inverse association of serum n-3 PUFA and a positive association of n-6 PUFA with colorectal adenoma risk. © 2008 Wiley-Liss, Inc.
Samples of a commercial fish oil were separately treated with various chemical compounds and then studied for their susceptibility
to rancidity by means of an accelerated oxidation test at 60°C.α-Tocopherol acetate and ascorbyl palmitate showed the lowest antioxidative effects among the group of seven chemicals. Anoxomer,
a synthetic phenolic polymer, had an antioxidative power comparable to that of ethoxyquin, butylated hydroxytoluene or butylated
hydroxyanisole when all were applied to the oil in the concentration of 0.02%. However, the most powerful antioxidant was
tertiary-butylhydroquinone (TBHQ), with an antioxidant efficiency twice that of the above-mentioned phenolic compounds when
used at only 0.01% concentration in the oil. Although TBHQ and Anoxomer proved to be potential compounds for preventing rancidity
in fish oils, their use is still hindered by the limited acceptance from the appropriate authorities.
Phospholipids have been reported to inhibit lipid oxidation in bulk oils, but very little is known about their influence on
oxidation in oil-in-water emulsions. In the present study, the impact of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) on lipid oxidation was studied in 1% stripped soybean oil-in-water (O/W) emulsions as a function
of DOPC concentration and pH (3 and 7). At pH 7.0, DOPC inhibited lipid oxidation in O/W emulsions, while DOPC was prooxidative
at pH 3.0. DOPC did not affect emulsion droplet charge or size at either pH 3.0 or 7.0. The antioxidant activity at pH 7.0
was observed in a series of phospholipids (PL) that varied in fatty acid unsaturation level and chain length as well as type
of phosphate head group. Overall, phosphatidylcholine with either oleic or palmitic acid were the most effective at inhibiting
lipid hydroperoxide and hexanal formation of all of the PL tested. Antioxidant mechanism of PL could not be ascribed to their
ability to decompose lipid hydroperoxides. It might be possible that, at pH 7.0, the PL antioxidant activity is related to
their ability to form structures within the lipid phase of the emulsions droplets or to chelate metals.
KeywordsOil-in-water emulsions–Phospholipids–Soybean oil–Oxidation–pH–Particle size–Zeta potential–Antioxidant activity–Hydroperoxides–Hexanal
Separation of crude oil from precooked and non-precooked skipjack tuna heads by a wet reduction method was carried out. Both heating temperature and time affected the separation and oil quality. Optimum conditions for separation of crude oil involved heating samples at 85°C for 30 min, followed by pressing at 140 tons/m2 using a hydraulic press. Yields of crude oil prepared from precooked and non-precooked samples were 2.8 and 4.8%, respectively. Crude oil obtained from non-precooked samples showed markedly higher quality than that from precooked samples. Crude oil from precooked samples had a higher peroxide value and much darker colour than that from non-precooked samples. However, crude oil from precooked samples had higher DHA (25.5%) than that from non-precooked samples (18.8%).
The nutritional benefits of ω-3 fatty acids make them excellent candidates as functional food ingredients if problems with oxidative rancidity can be overcome. Oil-in-water emulsions were prepared with 2% salmon oil, stabilized by 0.2% Brij 35 at pH 7. To determine the effects of heating (50–90 °C), ethylenediaminetetraacetic acid (EDTA), and calcium on the oxidative and physical stability of salmon oil-in-water emulsions, particle size, thiobarbituric acid reactive substances (TBARS), and lipid hydroperoxides were measured. The heat-processed emulsions showed no significant difference, in particle size, TBARS or hydroperoxides during storage, from unheated emulsions. Above 2.5 μM, EDTA dramatically decreased lipid oxidation in all samples. Addition of calcium to emulsions containing 7.5 μM EDTA significantly increased both TBARS and hydroperoxide formation when calcium concentrations were 2-fold greater than EDTA concentrations. These results indicate that heat-processed salmon oil-in-water emulsions with high physical and oxidative stability could be produced in the presence of EDTA.
The rationale for supplementation with n-3 fatty acids to promote the health of the gastrointestinal tract lies in the antiinflammatory effects of these lipid compounds. The first evidence of the importance of dietary intake of n-3 polyunsaturated fatty acids was derived from epidemiologic observations of the low incidence of inflammatory bowel disease in Eskimos. The aim of this paper was to briefly review the literature on the use of n-3 fatty acids in inflammatory bowel disease (ulcerative colitis and Crohn disease), the results of which are controversial. The discrepancies between studies may reside in the different study designs used as well as in the various formulations and dosages used, some of which may lead to a high incidence of side effects. Choosing a formulation that lowers the incidence of side effects, selecting patients carefully, and paying strict attention to experimental design are critical when investigating further the therapeutic potential of these lipids in inflammatory bowel disease.
To date, epidemiologic studies investigating intake of n-3 and n-6 polyunsaturated fatty acids and risk of colorectal cancer are limited, and results remain inconsistent. This is the first prospective study to show the association by subsite (proximal colon, distal colon, rectum). To clarify the role of n-3 and n-6 polyunsaturated fatty acids intake in colon carcinogenesis, we conducted a large, population-based prospective study, characterized by high fish consumption and a wide range of n-3 polyunsaturated fatty acids intakes. Subjects were followed from response to a lifestyle questionnaire in 1995-1999 through 2006. During 827,833 person-years of follow-up (average 9.3 years), we identified 1,268 new colorectal cancer cases (521 colon and 253 rectal for men; 350 colon and 144 rectal for women). Compared to the lowest quintile, the relative risk and 95% confidence interval of developing cancer among the fifth quintile of marine n-3 polyunsaturated fatty acids intake were 0.60 and 0.31-1.14, respectively (p for trend = 0.04) in the colon in women and 0.35 and 0.14-0.88 (p for trend = 0.05) and 1.82 and 0.79-4.20 (p for trend = 0.16) in the proximal and distal colon, respectively, in men. For rectal cancer, the dose response for marine n-3 polyunsaturated fatty acids s was unclear; rather, we observed U-shaped associations in men and women. We found no evidence that n-6 polyunsaturated fatty acids increases or the n-3/n-6 ratio decreases the risk of colorectal cancer. Our results suggest that intake of marine n-3 polyunsaturated fatty acids may be inversely related to the risk of cancer in the proximal site of the large bowel.
Inflammatory bowel diseases (IBD) increase the risk of developing colorectal cancer. Dietary components that reduce inflammation are associated with lower cancer risk. The long-chain omega-3 fatty acid docosahexaenoic acid (DHA) is present in fish oil and has potent anti-inflammatory properties. The objective of this study is to determine whether dietary fish oil enriched with DHA (DFO) could reduce experimentally induced colitis and colon cancer risk in a mouse model. When SMAD3-/- mice are exposed to Helicobacter hepaticus, mild colitis is observed 4 weeks postinfection. Mice were fed isocaloric diets modified to include corn oil, safflower oil, or DFO (doses ranging from 0.75% to 6.00%) as the fatty acid source for 8 weeks. Mice were gavaged with H. hepaticus; DFO feeding was continued; and mice were sacrificed 4 weeks after infection. The colon and cecum were collected for histopathology. Spleens and mesenteric lymph nodes were collected and analyzed for T-cell populations using flow cytometry. Contrary to expectations, DFO induced severe colitis and adenocarcinoma formation. DFO consumption was associated with decreased CD8(+) cell frequency and diminished CD69 expression on CD4(+) and CD8(+) T-cell populations. Mice consuming DFO also exhibited higher FoxP3(+) CD25(+) CD4(+) T regulatory cell frequency, FoxP3 expression, and altered L-selectin expression during infection. We concluded that DFO-fed mice may be less equipped to mount a successful response to H. hepaticus infection, increasing colon cancer risk. These results support the need to establish a tolerable upper limit for DHA intake particularly in the context of chronic inflammatory conditions such as IBD.
Lipids are a major component of food and important structural and functional constituents of cells in biological systems. However, this diverse group of substances is prone to oxidation through various pathways. Their oxidative stability depends on a number of intrinsic and extrinsic factors, including the unsaturation of their fatty acids, composition of minor components, environment conditions, delivery techniques and use of antioxidants, among others. Lipid oxidation has detrimental effects on both food quality and human health, and efforts must be made to minimize oxidation and improve oxidative stability of lipid products. Antioxidant strategy has been successfully employed in the food industry for quality preservation of the food products and in the medicinal industry for risk reduction of numerous oxidative stress-mediated diseases. This tutorial review will provide important knowledge about lipid oxidation, including the mechanism and factors involved in oxidation, as well as strategies for improving oxidative stability of lipids.
Arachidonic acid metabolites formed by both the cyclooxygenase and lipoxygenase pathways may contribute to the clinical diarrhea and colitis of inflammatory bowel disease. Patients with active ulcerative colitis have increased levels of leukotriene B4 in their rectal mucosa, and these levels tend to correlate with severity of the disease. In this study, we evaluated the efficacy of ingestion of fish oil n-3-omega-fatty acids, inhibitors of leukotriene synthesis, in the treatment of ulcerative colitis. Eleven patients with ulcerative colitis of mild to moderate severity were studied in a 8-month, double-blind, placebo-controlled, crossover trial of dietary supplementation with fish oil, which provided about 4.2 g of omega-3- fatty acids per day. A disease activity index based on patient symptoms and sigmoidoscopic appearance was used to assess efficacy. Mucosal leukotriene B4 production was measured by radioimmunoassay. Mean disease activity index declined 56% for patients receiving fish oil and 4% for patients on placebo (p less than 0.05). There were no statistically significant differences in histopathologic scores or colonic mucosal leukotriene B4 levels. All patients tolerated fish oil ingestion and showed no alteration in routine blood studies. No patient worsened; anti-inflammatory drugs could be reduced or eliminated in eight patients (72%) while receiving fish oil. We conclude that fish oil dietary supplementation results in clinical improvement of active mild to moderate ulcerative colitis but is not associated with significant reduction in mucosal leukotriene B4 production, compared with placebo therapy. Further studies are needed to elucidate the mechanism of action and optimal dose and duration of fish oil supplementation in ulcerative colitis.
Feeding of purified diets containing fish oil without added antioxidant leads to rapid autoxidation of the oil and the possibility of artifactual results due to the feeding of autoxidation products. Purified diets containing menhaden oil without any added antioxidant deteriorate quickly. Peroxide value of the diet is elevated 5- to 6-fold within 24 h and 12-fold within 48 h when exposed to air at room temperature. Addition of 0.02% t-butylhydroquinone to the fish oil prevents this deterioration for at least 72 h. Determination of fatty acid composition is not a sensitive indicator of diet integrity. Supplementation of fish oil diets with vitamin E to help protect against in vivo peroxidation is discussed.
To examine the relative roles of dietary fibre, anti-oxidant vitamins and fish oils in the relatively low incidence of colon cancer in coloured West Coast fishermen.
Dietary intake survey, based on food frequency questionnaire and household surveys. Blood sampling for vitamin and fatty acid concentrations.
Isolated West Coast fishing villages (sample population) and urban Cape Town inhabitants (controls).
101 male and female West Coast fishermen over the age of 40 years, and 99 age- and sex-matched urban whites.
Dietary analysis by 'Foodfinder' technique, and nutrient blood levels. Statistical analysis using SASR program version 6.
An analysis of the number of recorded cases of colorectal cancer over a period of 5 years leading up to the study confirmed a lower rate of colorectal cancer in the West Coast fishermen than in the Cape Town population: fishermen 6 cases/120000, urban whites 677/2 million. A significantly higher proportion of fishermen were smokers, had hypertension and gave a history of previous tuberculosis infections. Vitamin supplementation was noted in one-third of whites but in no fishermen. The results of the dietary analysis (mean (SD)) demonstrated that fishermen consumed less fibre (9.9 (4.7) g/d v. 17.4 (7.2) g/d; P < 0.01) and less fruit and vegetables (190 g/d v. 365 g/d; P < 0.001), with a lower intake of vitamin C, thiamin, riboflavin, vitamin B6 and folate. Sodium intake was higher in fishermen, whereas intakes of potassium, magnesium, calcium, iron, zinc and copper were lower. In addition, the daily intake of omega-3 fatty acids (fish oils), docosahexaenoic acid (C22:6) and eicosapentaenoic acid (C20:5) in the West Coast population was considerably higher (0.71 (0.51) g/d v. 0.14 (0.09) g/d; P < 0.0001 and 0.37 (0.3) g/d v. 0.05 (0.05) g/d; P < 0.0001, respectively) than in the urban population owing to their higher intake of fish (110 g v. 30 g/d; P < 0.001). Plasma fatty acids correlated positively with these dietary intake figures, showing fishermen to have higher levels of circulating omega-3 fatty acids, C20:5 (3.9 (1.8)% v. 0.66 (0.29)%; P < 0.001) and C22:6 (5.6 (1.8) v. 2.9 (0.08)%; P < 0.001) and lower levels of omega-6 fatty acids, C18:2 and C20:3 (29.7 (4.7)% v. 33.5 (5.6)%; P < 0.05 and 0.85 (0.48)% v. 1.5 (0.47)%; P < 0.001, respectively) compared with the urban group.
The low incidence of colorectal carcinoma in West Coast fishermen might be explained by the protective effects of fish (omega-3) oils, but not by other "protective' dietary items such as fibre, anti-oxidant vitamins or calcium. The high incidence of hypertension may be related to a higher sodium intake, accompanying high consumption of salted fish, or to the higher prevalence of tobacco smoking.
Although long-chain n-3 polyunsaturated fatty acids (Ln-3 PUFA), which are abundant in fish, have shown protective effects on colorectal cancer in laboratory studies, epidemiological studies to date have not been consistent. We evaluated the relationship of consumption of fish and Ln-3 PUFA to the colon and rectal cancer risk in the two cohorts of the Japan Public Health Center-based prospective study of 42,525 men and 46,133 women. Dietary and other exposure data were obtained between 1990 and 1994. Through December 1999, 705 cases of colon and rectal cancer were documented. When data from the two cohorts were pooled, multivariable relative risks (RRs) for the highest quartile compared with the lowest quartile of fish consumption were 1.07 (95% confidence interval, CI = 0.77-1.48) for colon cancer and 0.95 (95% CI = 0.63-1.43) for rectal cancer with no dose-risk trend. RRs for the highest quartile compared with the lowest quartile of eicosapentaenoic acid consumption were 1.05 (95% CI = 0.76-1.46) for colon cancer and 0.91 (95% CI = 0.60-1.38) for rectal cancer with no dose-risk trend. This study does not support the role of fish and Ln-3 PUFA in the etiology of colon and rectal cancer in this population whose fish consumption was high and the variation in Ln-3 PUFA consumption was large.
Physicochemical, microbiological and oxidative changes during refrigerated storage of n-3 PUFA enriched cooked meat sausages with partial NaCl substitution
- L Marchetti
- S C Andreś
- A N Califano
- C L Thang
- J I Boye
- H N Shi
- X Zhao
Marchetti, L.; Andreś, S. C.; Califano, A. N. Physicochemical,
microbiological and oxidative changes during refrigerated storage of n-3 PUFA enriched cooked meat sausages with partial NaCl
substitution. J. Food Process. Preserv. 2017, 41, No. e12920.
(14) Thang, C. L.; Boye, J. I.; Shi, H. N.; Zhao, X. Effects of
supplementing different ratios of omega-3 and omega-6 fatty acids in
western-style diets on cow's milk protein allergy in a mouse model.
Mol. Nutr. Food Res. 2013, 57, 2029−2038.