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Effect of diets that differ in protein type and density on the body weight of Wistar rats. Values are means Ϯ SEM, n ϭ 8. Means without a common letter differ, P Ͻ 0.05.
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A high-protein diet can reduce body weight and increase insulin sensitivity, but whether the type of dietary protein affects these outcomes is unknown. We hypothesized that feeding insulin-resistant rats a high-protein diet (32%) containing whey protein concentrate (WPC) would reduce body weight and tissue lipid levels and increase insulin sensitiv...
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Context 1
... gain and energy intake. Energy intake was in- versely related to dietary protein density. Rats fed the high-protein diets consumed 19% less energy/d than rats fed the low-protein diets (P 0.05; Fig. 1). However, dietary protein type did not affect energy intake. The rats fed the 32% WPC diet gained 4 and 10% less weight than the rats fed the 8% protein diets and the 32% RM diet, respectively (P 0.001; Fig. ...
Context 2
... to dietary protein density. Rats fed the high-protein diets consumed 19% less energy/d than rats fed the low-protein diets (P 0.05; Fig. 1). However, dietary protein type did not affect energy intake. The rats fed the 32% WPC diet gained 4 and 10% less weight than the rats fed the 8% protein diets and the 32% RM diet, respectively (P 0.001; Fig. ...
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Citations
... A meal containing α-lactalbumin maintains fat oxidation and quickly provides amino acids for use during exercise, resulting in improved athletic training efficiency. (Belobrajdic et al., 2004). ...
... The whey protein fraction has been shown to reduce C-reactive protein levels (CRP) when consumed in individuals with increased basal levels of CRP (e.g., individuals with obesity, hypertension, or COPD; Zhou et al., 2015). Likewise, in rodents, whey protein given along with an HFD, diminished weight gain (Royle et al., 2008;Boscaini et al., 2020), increased insulin sensitivity (Belobrajdic et al., 2004), and reduced liver steatosis (Shertzer et al., 2011). The mechanism behind the effects of whey protein on inflammation and insulin sensitivity is not fully understood. ...
... A high-protein diet can reduce body weight and increase insulin sensitivity. Whey protein intake in concentrate in insulin-resistant experimental animals reduces tissue lipid levels and body fat percentage, reduces body weight by 4%, reduces plasma insulin concentration by 40% and increases insulin sensitivity compared to a protein-rich diet of red meat (63). Weight loss under energy restriction is associated with high levels of calcium and whey protein in the diet (64). ...
The values of whey as a healthy and therapeutically useful drink are well known, and in folk medicine it has often been attributed miraculous powers and possibilities. This is nothing new, bearing in mind that in 460 BC, the father of medicine Hippocrates emphasized the value of whey in the treatment of tuberculosis, jaundice, diseases of the liver and digestive system, skin diseases and many other diseases. Whey is obtained during milk processing and cheese production, where it is present in almost 90% of the total mass. The composition of whey is specific. Water makes up to 93% of the composition, the rest consists of sugars and minerals, B vitamins, as well as a great wealth of probiotic bacteria. Whey is the largest source of essential amino acids compared to plant or animal sources. The concentration of amino acids in whey is 43% compared to oats (21%), wheat husk (21%) and wheat (22%), milk 39%, casein 34% and eggs 32%) or meat proteins (38%). Whey proteins contain almost 50% of essential amino acids and about 26% of branched-chain amino acids. Their composition is similar to the amino acid composition of human muscles, which allows their faster absorption than other sources of protein. The share of free amino acids in whey is 4 to 10 times higher than in milk. They have a significant effect on protein synthesis and a very strong anabolic effect in the body. Whey amino acids stimulate skeletal muscle regeneration, reduce fatigue, increase synthesis, and reduce muscle protein breakdown. Whey proteins increase the levels of antioxidant enzymes, especially glutathione and catalase. Positive effect on the reduction of the levels of TBARS (thiobarbituric acid reactive substance) is an important indicator of the decreasing process of lipid peroxidation. Reduction of oxidative stress process in the liver has positive consequences on inflammation and the content of lipids in the liver tissue and atherosclerosis process. Recent research indicates a positive effect on glucose metabolism, improving insulin sensitivity and preventing the development of fatty liver syndrome and type 2 diabetes. It has a positive effect on weight control, so whey proteins are integral parts of healthy medical diets, sport drinks, with approved efficacy in obesity treatments. Essential amino acids also act as neurogenic active substances, and they are also known as precursors of biogenic amines and neurotransmitters, so it is logical that there is a growing interest in researching their potential in psychiatry.
... Whey protein can maintain uptake of glucose in the blood and increase insulin sensitivity. Drinking milk containing protein or consuming whey with carbohydrates can increase plasma insulin as a mechanism to decrease blood glucose or maintain blood glucose levels within normal limit [14,15]. Whey protein is absorbed faster than casein and can reduce postprandial glucose response. ...
... Several studies from animal trials, healthy individuals, and type 2 diabetes mellitus individuals show that dairy whey proteins may significantly decrease the postprandial glucose response because of the insulinotropic effect of its amino acids [14,18,19]. Another study found that the consumption of peptides and intact whey protein reduced the glucose response in a dose-dependent manner in healthy subjects [20]. ...
Background: High-protein milk is a complex food that contains several potentially bioactive compounds that might affect blood glucose and cholesterol. Epidemiological data indicate that high-protein milk consumption is associated with a decrease in the prevalence of metabolic disorders or maintaining metabolic health.Objective: This study aimed to analyze the effect of high-protein milk on cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, and fasting blood glucose.Methods: This study used an experimental trial with the designed randomized controlled trial. The subjects were divided into two groups: 24 subjects in the treatment group and 23 subjects in the control group. The treatment group was given high-protein milk and nutritional education for 90 days. The control groups were given nutritional education.Results: The results showed that blood glucose did not have a significant difference between the two groups (p>0.05), but it decreased 1.75±3.6 mg/dl after high-protein milk intervention. Blood cholesterol and LDL showed significant differences between the two groups (p<0.05). HDL and triglycerides showed no significant difference between the two groups (p>0.05).Conclusion: Intervention of high-protein milk could significantly reduce cholesterol and LDL levels and reduce blood glucose after 90 days of intervention in the young adult age group. High-protein milk can be a recommendation to prevent metabolic syndrome.
... Correspondingly, the reduced TG concentration was associated with downregulated mRNA level of SREBPF1, FASN, ACACα, and SCD ( Figure 2). Similarly, previous studies have shown that high protein intake reduces hepatic lipid accumulation and plasma TG concentration in rats and humans [35,36], alleviates steatosis [37], and reduces body weight [38]. SREBPs is a master regulator of lipo-and sterol-genic gene transcription on lipid homeostasis of vertebrate cells [8,39]. ...
Amino acids serve not only as building blocks for proteins, but also as substrates for the synthesis of low-molecular-weight substances involved in hepatic lipid metabolism. In the present study, eighteen weaned female piglets at 35 days of age were fed a corn- and soybean meal-based diet containing 20%, 17%, or 14% crude protein (CP), respectively. We found that 17% or 20% CP administration reduced the triglyceride and cholesterol concentrations, while enhanced high-density lipoprotein cholesterol (HDL-C) concentration in serum. Western blot analysis showed that piglets in the 20% CP group had higher protein abundance of hormone-sensitive triglyceride lipase (HSL) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), as compared with other groups. Moreover, the mRNA expression of sterol regulatory element binding transcription factor 1 (SREBPF1), fatty acid synthase (FASN), and stearoyl-CoA desaturase (SCD) were lower in the 17% or 20% CP group, compared with those of the piglets administered with 14% CP. Of note, the mRNA level of acetyl-CoA carboxylase alpha (ACACα) was lower in the 17% CP group, compared with other groups. Additionally, the mRNA level of lipoprotein lipase (LPL), peroxisome proliferator-activated receptor alpha α (PPARα), glucose-6-phosphatase catalytic subunit (G6PC), and phosphoenolpyruvate carboxykinase 1 (PKC1) in the liver of piglets in the 20% CP group were higher than those of the 14% CP group. Collectively, our results demonstrated that dietary CP could regulate hepatic lipid metabolism through altering hepatic lipid lipogenesis, lipolysis, oxidation, and gluconeogenesis.
... 17 Another group demonstrated that whey protein administration in HF-fed rats with established insulin resistance reduced energy intake and adipose tissue weight and enhanced insulin sensitivity more effectively than red meat protein. 18 In severely insulin-resistant ob/ob and KK-Ay mice, whey peptides were shown to increase insulinotrophic activity 19 and improve insulin sensitivity in the liver and skeletal muscle. 20 However, a study by Gürgen et al. suggested that consumption of whey for four weeks increases systemic inflammation and liver damage in rats. ...
... Prior studies have suggested that whey protein and peptide supplementation influences obesity and glucose intolerance in mice subjected to an obesogenic diet. 17,18 However, it remains unclear as to whether endogenous or exogenous digestion of whey elicits a greater metabolic response in vivo. To examine this, we fed male C57BL/6J mice an HF diet for 13 weeks and concurrently added 1 mg ml −1 of WPI or WPH to the drinking water (Fig. 1A). ...
... Thus, our results stand in contrast to other long-term studies employing WPI suggesting that milk-derived proteins have an insulin-sensitizing effect in vivo. 18,[22][23][24] The primary difference underlying this effect is likely the dose of whey chosen. Whereas we used a dose of 1 mg ml −1 WPI, oral doses of 75 mg ml −1 (ref. ...
Consumption of milk-derived whey proteins has been demonstrated to have insulin-sensitizing effects in mice and humans, in part through the generation of bioactive whey peptides. While whey peptides can prevent insulin resistance in vitro, it is unclear whether consumption of whey peptides can prevent obesity-induced metabolic dysfunction in vivo. We sought to determine whether whey peptides consumption can protect from high fat (HF) diet-induced obesity and dysregulation of glucose homeostasis. Male C57BL/6J mice were fed either a low or HF diet for 13 weeks. HF diet fed mice were provided drinking water with no addition (control), undigested whey protein isolate (WPI, 1 mg ml-1) or whey protein hydrolysate (WPH, 1 mg ml-1) throughout the diet regimen. Mice consuming WPH gained more body weight and were more glucose intolerant compared to those consuming WPI or water only. Despite increased body weight gain, perigonadal adipose tissue weight and lipid accumulation were unchanged. However, excess lipids accumulated ectopically in the liver and skeletal muscle in mice consuming WPH, which was associated with elevated inflammatory markers systemically and in adipose tissue, liver, and skeletal muscle. In skeletal muscle, mitochondrial fat oxidation and electron transport chain proteins were decreased with WPH consumption, indicative of mitochondrial dysfunction. Taken together, our results demonstrate that WPH, but not WPI, exacerbates HF-induced body weight gain and impairs glucose homeostasis, which is accompanied by increased inflammation, ectopic fat accumulation and mitochondrial dysfunction. Thus, our results argue against the use of dietary whey peptide supplementation as a preventative option against HF diet-induced metabolic dysfunction.
... Belobrajdic et al. [32] found that dietary supplementation with whey protein concentrate reduced the body weight of rats. e amount of subcutaneous and carcass fat in rats fed the concentrate was lower than that of rats fed red meat [33]. Moreover, whey protein decreased the fat mass of animals with diet-induced obesity, while increasing the lean mass [27]. ...
This study was conducted to evaluate the physicochemical properties of whey-fed pork loin subjected to salting, dry aging, and sous vide cooking. We compared raw and treated pork loin from pigs fed a basal diet (control) and those fed a diet supplemented with whey powder. Treated pork was salted, dry aged for 0–30 d, and then cooked using sous vide. The crude fat, total lipid, and cholesterol content and shear force of raw whey powder-fed pork loin were significantly lower than those of the control, while the crude protein content was higher. Cooking loss, hardness, and gumminess were found to decrease with the aging period in sous vide-treated pork. Dietary supplementation with whey had positive effects on pork color stability, texture, and sensory evaluation, and it significantly inhibited the growth of bacteria. The results suggest that supplementing the diet of pigs with whey powder can enhance meat quality, especially when combined with salting, dry aging, and sous vide cooking.
... 24 In studies of the effect of high-protein diets from different sources on weight loss, compared with other animal proteins such as red meat, casein and whey proteins are more effective in preventing weight gain and accretion of adipose mass. 25,26 Milk protein consists of 80% casein and 20% whey protein. 27 Based on the digestible indispensable amino acid score, dairy proteins are perhaps the highest quality protein. ...
High protein diets are known to reduce weight and fat deposition. However, there have been only a few studies on the efficacy of different types of high protein diets in preventing obesity. Therefore, the emphasis of this study lies in comparing the efficacy of two high protein diets (milk protein and whey protein) in preventing obesity and exploring specific mechanisms. Eighty Sprague Dawley rats were divided into two groups and fed with milk protein concentrate (MPC) and whey protein concentrate (WPC) for 12 weeks. Each group was divided into four levels: two low fat regimens with either low or high protein content (L-14%, L-40%) and two high fat regimens with either low or high protein content (H-14%, H-40%). The studies we have performed showed that rats treated with MPC at the 40% protein level can significantly reduce body weight, fat weight and fat ratio gain induced by a high fat diet, while the protein level in the WPC group had no effect on body weight or body fat in rats fed with a high-fat diet. What is more, rats fed with MPC at the H-40% energy level showed a significant decrease in plasma triglyceride, total cholesterol and low-density lipoprotein cholesterol levels and a significant increase in plasma high-density lipoprotein cholesterol levels compared with the H-14% energy level group. In contrast, in the WPC groups, increasing the protein content in high fat diets had no significant influence on plasma lipid levels. The results of the amino acid composition of the two proteins and plasma showed that the MPC diet of 40% protein level increased the transsulfuration pathway in rats, thereby increasing the level of H2S. The research work has shown that not all types of high protein diets can effectively prevent obesity induced by high fat diets, depending on the amino acid composition of the protein.
... It influences on appetite and hunger controlling hormones [74]. A high-protein diet reduces energy intake and adiposity and that whey protein is more effective than red meat in reducing body weight gain and increasing insulin sensitivity [75]. In addition, whey protein helps control blood glucose levels and has been shown to be beneficial for weight management, both of which are often a concern for type-II diabetics. ...
... Whey protein isolate is a milk protein obtained after precipitation of casein during cheese production. Prolonged intake of whey protein isolate improves obesity, hepatosteatosis, insulin sensitivity, and glucose tolerance in mice fed a high-fat diet [11][12][13][14] , as well as in humans [15][16][17] . The effects of whey protein isolate on the altered expression of hepatic genes involved in hepatosteatosis, insulin resistance, glucose homeostasis, and the peripheral 5-HT system, however, remain unclear. ...
Abstract Insufficient expression of hepatic fibroblast growth factor 21 (FGF21) and stromal cell-derived factor 2 like 1 (Sdf2l1) reportedly leads to insulin resistance and hepatosteatosis in obesity and type 2 diabetes. On the other hand, increased expression of hepatic serotonin receptor 2a (htr2a) in diet-induced obesity contributes to hepatosteatosis. Here we show that increases in circulating FGF21 levels and expression of hepatic FGF21 preceded weight gain, hyperinsulinemia, and hyperglycemia in C57BLJ6 mice fed a high-fat diet. Expression of hepatic htr2a and Sdf2l1 increased in insulin-resistant mice fed a high-fat diet. Intake of whey protein isolate decreased plasma FGF21 levels and expression of hepatic FGF21 in mice fed either a high-fat diet or a chow diet, whereas it only suppressed the overexpression of hepatic Sdf2 and htr2a in insulin-resistant mice fed a high-fat diet. Moreover, intake of whey protein isolate decreased plasma serotonin levels in mice fed either a high-fat diet or a chow diet. Genetic inhibition of tryptophan hydroxylase 1 decreased hepatic FGF21 expression and plasma FGF21 levels in mice. These findings suggest that increased hepatic FGF21 production precedes diet-induced weight gain, hyperinsulinemia, and hyperglycemia, and that intake of whey protein isolate could inhibit hepatic FGF21 production by suppressing peripheral serotonin synthesis.
