Written by Team MD
31 January 2014

 Whey Protein: More Thermogenic than Soy or Casein

Whey Protein Benefits - More than just a Protein!

 

 

wheythermoHere's the skinny on whey protein benefits: Just as we know that not all carbs or fats are treated the same by your body, we also know that proteins are unique in their own right. Casein (the slow protein) and whey protein do a whole lot more than just enhance protein synthesis. In a new study, rats were administered whey protein or casein and put through a muscle overload protocol. Researchers strapped tiny weights on the rat subjects’ backs and electrocuted the floor, which made the rats jump up— similar to a person doing weighted jump squats. At the end of the study, it was found that whey protein reduced muscle damage but also enhanced liver antioxidant levels.

Interestingly, levels of TBARS (ThioBarbituric Acid Reactive Substances)— a well-known biomarker of oxidative damage or free radical damage that cause cell destruction— are known to increase in plasma after weightlifting; however, TBARS were lowered after whey protein consumption. Additionally, whey protein increased total liver glutathione levels, which is a potent antioxidant. Thus, whey protein benefits include potent antioxidant properties both in muscle and in the liver.

Another interesting finding was that the rats were administered the exact same amount of protein, yet the whey protein group had larger increases in muscle mass. These results suggest that the potent biochemical antioxidant actions of whey protein mediated a reduction in cellular damage to both liver and muscle, resulting in enhanced muscle and bodyweight.1 In terms of the anabolic responses, whey may have an advantage over casein in that it’s a potent antioxidant. It’s also been demonstrated that whey has the ability to inhibit angiotensin II, which is a potent vessel constrictor— so you may even get better muscle pumps with whey protein compared to other protein powders.

Whey Protein Hydrolysates: Get Better Pumps!

 Whey protein is not only a “fast-acting” protein as it has been known for years, but it has many more benefits for bodybuilding. It may help you get better pumps in the gym. The vascular endothelium is a single-cell layer in blood vessels that influences vascular health and risk of disease by regulating vasoconstriction and vasodilation, blood pressure, blood clotting, etc.2 Bioactive peptides derived from food, especially milk proteins, exert a wide range of biological actions including decreased blood pressure and improved endothelial function. Milk is a rich source of angiotensin-converting enzyme (ACE) inhibitory peptides. ACE inhibition prevents the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. Many people with high blood pressure are prescribed ACE-inhibitor drugs to lower blood pressure, but bodybuilders may get a similar effect with whey protein hydrolysates.

Most bodybuilders take a nitric oxide (NO) product before exercise to increase muscle pumps, but taking a new and novel whey protein shake may also help with getting better pumps. A researcher from the University of Connecticut investigated a new whey protein hydrolysate and its effects on vasodilation. The active whey supplement was a proprietary peptide isolated from a whey protein hydrolysate (NOP-47, Glanbia Nutritionals, Twin Falls, ID). Subjects consumed one serving a day of NOP-47 or a placebo for two weeks. At the end of the study, researchers found that acute ingestion of NOP-47 significantly increased blood vessel dilation at 30, 60 and 90 minutes, post-ingestion. This means the daily ingestion of a whey protein hydrolysate may be a great way to facilitate blood flow in the gym, as a single serving enhanced vasodilation 90 minutes after consumption. OK, but what about burning fat— which protein is #1 in that category?

What About Thermogenesis? Which Protein Blend is Best?

 Scientists are finally starting to realize that increasing protein can accelerate weight loss. Protein not only increases energy expenditure, but also decreases energy intake through mechanisms that influence appetite control. Their addition to foods, meals, and diets decreases the glycemic index and, when exchanged for carbohydrates, the glycemic load as well— with potential benefits for glucose tolerance and insulin sensitivity. The energy cost of digesting, absorbing, and metabolizing protein (23 percent) is greater than that of either carbohydrate (6 percent) or fat (3 percent).3 Researchers from Switzerland investigated the thermogenic effects of three proteins: whey protein, casein, and soy. Subjects were men and women who consumed a shake consisting of 50 percent protein, 40 percent carbohydrates, and 10 percent fats. So which protein came out on top for being the most thermogenic? You guessed it: WHEY PROTEIN WAS MORE THERMOGENIC THAN ANY OTHER PROTEIN.7 The consumption of whey protein also resulted in enhanced fat oxidation, compared to soy protein. The scientists had a few ideas as to why whey was more thermogenic than other proteins.

 1) Whey proteins are more rapidly digested and absorbed than casein, and this improves protein synthesis. Increased protein synthesis has been proposed as one possible mechanism responsible for the increased thermogenesis observed after high-whey protein consumption. After consumption of whey protein, the rate of protein synthesis is faster— twofold greater (68 percent, compared to 31 percent with casein). Ever notice when you eat a big steak, you start sweating? The energy cost of digesting, absorbing, and metabolizing protein (23 percent) is greater than that of either carbohydrate (6 percent) or fat (3 percent).3 This means the greater increases in protein synthesis resulted in a net greater energetic cost, which increased thermogenesis. It takes energy to increase protein synthesis! Consequently, differences in the rate of protein synthesis after whey, casein, and soy ingestion may explain the small, but significant, differences in thermic effect observed after whey protein.

 2) Researchers speculated that increased glucagon secretion might enhance fat oxidation. Whey protein, contrary to what one would expect, promotes fat loss by enhancing the release of glucagon (builds muscle, burns fat). Glucagon stimulates the breakdown of glycogen stored in the liver. When blood glucose levels are high, the liver takes up large amounts of glucose. Under the influence of insulin, much of this glucose is stored in the form of glycogen. Glucagon activates hepatic gluconeogenesis. Gluconeogenesis is the pathway by which substrates such as amino acids are converted to glucose. As such, it provides another source of glucose for blood.

 Glucagon also appears to have a minor effect of enhancing lipolysis of triglycerides in adipose tissue, which could be viewed as an additional means of conserving blood glucose by providing fatty acid fuel to most cells. For example, Glucagon-like peptide-2 (GLP-2) is a nutrient-regulated intestinotrophic hormone derived from proglucagon in the distal intestine. GLP-2 has been found to be stimulated after whey protein consumption.4 Another study found that insulin and glucagon responses increased with increased protein load for whey protein and casein, but the effect was more pronounced for glucagon after whey consumption. A higher dose of protein or its hydrolysate will result in a lower insulin:glucagon ratio, an important parameter for the control of postprandial substrate metabolism.

Another study found that insulin and glucagon responses to whey protein resulted in lower respiratory quotients, indicative of increased fat oxidation, after a breakfast meal containing whey protein— compared to meals containing casein or soy.5 Whereas it is tempting to suggest that the elevated glucagon concentrations observed after whey consumption may have interfered with insulin’s antilipolytic effects and permitted fat oxidation to continue at, more or less, fasting concentrations, evidence for the lipolytic effects of glucagon after whey protein consumption has been reported.6 This is just another reason to throw some whey protein powder in your shaker cup when coming home from the gym!

References:

 1. Haraguchi FK, Silva ME, Neves LX, Dos Santos RC, Pedrosa ML. Whey protein precludes lipid and protein oxidation and improves body weight gain in resistance-exercised rats. Eur J Nutr, 2010 Nov 3.

 2. Ballard KD, Bruno RS, Seip RL, Quann EE, Volk BM, Freidenreich DJ, Kawiecki DM, Kupchak BR, Chung MY, Kraemer WJ, Volek JS. Acute ingestion of a novel whey-derived peptide improves vascular endothelial responses in healthy individuals: a randomized, placebo-controlled trial. Nutr J, 2009 Jul 22;8:34.

 3. Flatt JP. The biochemistry of energy expenditure. In: Bray GA, ed. Recent advances in obesity research. London, United Kingdom: Newman Publishing, 1978:211-28.

 4. Liu X, Murali SG, Holst JJ, Ney DM. Whey protein potentiates the intestinotrophic action of glucagon-like peptide-2 in parenterally fed rats. Am J Physiol Regul Integr Comp Physiol, 2009 Nov;297(5):R1554-62. E-pub, 2009 Sep 23.

 5. Alfenas Rde C, Bressan J, de Paiva AC. Effects of protein quality on appetite and energy metabolism in normal weight subjects. Arq Bras Endocrinol Metabol, 2010;54:45-51.

 6. Claessens M, Saris WH, van Baak MA. Glucagon and insulin responses after ingestion of different amounts of intact and hydrolysed proteins. Br J Nutr, 2008 Jul;100(1):61-9.

7. Acheson KJ, Blondel-Lubrano A, Oguey-Araymon S, Beaumont M, Emady-Azar S, Ammon-Zufferey C, Monnard I, Pinaud S, Nielsen-Moennoz C, Bovetto L. Protein choices targeting thermogenesis and metabolism. Am J Clin Nutr, 2011.

 Whey Protein Results in Higher Fat Oxidation and Lower Appetite Than Egg Albumin

 

New research further extends the benefits of whey protein for decreasing body fat. Researchers reported in the journal Obesity that whey protein could increase fat oxidation and reduce appetite more than egg protein. Researchers fed rats three types of protein for a 10-week study: a control diet, a high-protein whey protein diet, or a high-protein albumin diet (egg protein). Food intake, bodyweight, body fat, respiratory quotient (RQ), glucagon-like peptide-1 (GLP-1), and other hormones were measured during and/or at the end of the study.

 At the conclusion of the study, body fat and bodyweight gain was lower in rats fed whey protein and egg albumin, compared to the control diet, which is no surprise. Interestingly, the cumulative food intake measured over the 10-week study was lower in the whey protein group, compared to the control and egg albumin groups. More importantly, the rats fed whey protein had higher fat oxidation than rats fed egg albumin protein.

In conclusion, although dietary whey and egg protein each decrease body fat accumulation and bodyweight gain, the mechanisms involved appear to be different. The rats fed the high-protein whey diet showed decreased food intake and increased fat oxidation, which may contribute to the effects of whey protein on body fat.

 

Reference:

 

Zhou J, Keenan MJ, Losso JN, Raggio AM, Shen L, McCutcheon KL, Tulley RT, Blackman MR, Martin RJ. Dietary Whey Protein Decreases Food Intake and Body Fat in Rats. Obesity, (Silver Spring). 2011 Feb 17.

 

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