Micellar Casein

Diets higher in quality protein have been shown to result in greater weight loss, greater fat loss, and greater preservation of lean body mass (muscle) when compared to diets lower in protein.

Dietary protein for athletes: from requirements to metabolic advantage.

Phillips SM.

Appl Physiol Nutr Metab. 2006 Dec; 31(6):674-54.

The Dietary Reference Intakes (DRI) specifies that the requirement for dietary protein for all individuals aged 19 y and older is 0.8 g protein per pound of body weight. This Recommended Dietary Allowance (RDA) is cited as adequate for all persons. This amount of protein would be considered by many athletes as the amount to be consumed in a single meal, particularly for strength-training athletes. There does exist, however, published data to suggest that individuals habitually performing resistance and (or) endurance exercise require more protein than their sedentary counterparts. The RDA values for protein are clearly set at "...the level of protein judged to be adequate... to meet the known nutrient needs for practically all healthy people...” The RDA covers protein losses with margins for inter-individual variability and protein quality; the notion of consumption of excess protein above these levels to cover increased needs owing to physical activity is not, however, given any credence. Notwithstanding, diet programs (i.e., energy restriction) espousing the virtue of high protein enjoy continued popularity. A number of well-controlled studies are now published in which "higher" protein diets have been shown to be effective in promoting weight reduction, particularly fat loss. The term "higher" refers to a diet that has people consuming more than the general populations' average intake of approximately 15% of energy from protein, e.g., as much as 30%-35%, which is within an Acceptable Macronutrient Distribution Range (AMDR) as laid out in the DRIs. Of relevance to athletes and those in clinical practice is the fact that higher protein diets have quite consistently been shown to result in greater weight loss, greater fat loss, and preservation of lean mass as compared with "lower" protein diets. A framework for understanding dietary protein intake within the context of weight loss and athletic performance is laid out.

Casein protein has been shown to provide greater protein synthesis (muscle building) and much less protein breakdown (muscle loss) when compared directly to whey protein.

Slow and fast dietary proteins differently modulate postprandial protein accretion.

Boirie Y, Dangin M, Gachin, P, et. al.

Proc Natl Acad Sci U S A. 1997 Dec 23; 94(26):14930-5.

The speed of absorption of dietary amino acids by the gut varies according to the type of ingested dietary protein and the particular individual. This could affect postprandial protein synthesis, breakdown, and deposition. To test this hypothesis, two intrinsically 13C-leucine-labeled milk proteins, casein and whey protein, of different physicochemical properties were ingested as one single meal by healthy adults. Postprandial whole body leucine kinetics were assessed by using a dual tracer methodology. Whey proetin induced a dramatic but short increase of plasma amino acids. Casein induced a prolonged plateau of moderate hyperaminoacidemia, probably because of a slow gastric emptying. Whole body protein breakdown was inhibited by 34% after Casein ingestion but not after whey protein ingestion. Postprandial protein synthesis was stimulated by 68% with the whey protein meal and to a lesser extent (+31%) with the Casein meal. Postprandial whole body leucine oxidation over 7 h was lower with Casein (272 +/- 91 micromol.kg-1) than with whey protein (373 +/- 56 micromol.kg-1). Leucine intake was identical in both meals (380 micromol.kg-1). Therefore, net leucine balance over the 7 h after the meal was more positive with Casein than with whey protein (P < 0.05, Whey protein vs. Casein). In conclusion, the speed of protein digestion and amino acid absorption from the gut has a major effect on whole body protein anabolism after one single meal. By analogy with carbohydrate metabolism, slow and fast proteins modulate the postprandial metabolic response, a concept to be applied to wasting situations.

Note: This study is considered the premier casein study and compared micellar casein head to head with whey protein for absorptive and digestive characteristics. The casein used was micellar (whole) casein. The major difference noted in this study was the short lived increase in the amino acid pool produced by whey protein as compared to the much longer increase shown by micellar casein. Also important to note is the implication that whey protein sources may provide a benefit as part of a post exercise drink due to the very rapid increase in amino acids seen in this study. Increasing the amino acid pool just after exercise may provide a benefit to muscle recovery and decreasing catabolism.

Increasing the amount of protein consumed in a diet will result in a significantly lower amount of weight gained following weight loss. This is due in part to proteins ability to increase satiety and thermogenesis.

Significance of protein in food intake and body weight regulation.

Westerterp-Plantenga MS.

Curr Opin Clin Nutr Metab Care. 2003 Nov; 6(6):635-8.

PURPOSE OF REVIEW: To highlight the underexposed but important role of protein in food intake and body weight regulation. RECENT FINDINGS: Protein plays a key role in food intake regulation through satiety related to diet-induced thermogenesis. Protein also plays a key role in body weight regulation through its effect on thermogenesis and body composition. A high percentage of energy from dietary protein limits body weight (re)gain through its satiety and energy inefficiency related to the change in body composition. SUMMARY: Protein is more satiating than carbohydrate and fat in the short term, over 24 h and in the long term. Thermogenesis plays a role in this satiety effect, but the role of satiety hormones still needs to be elucidated. On the short-term 'fast' proteins are more satiating than 'slow' proteins, and animal protein induces a higher thermogenesis than vegetable protein. In the longer term the higher post absorptive satiety and thermogenesis are sustained irrespective of the protein source. High-protein diets affect body weight loss positively only under ad-libitum energy intake conditions, implying also a decreased energy intake. Body composition and metabolic profile are improved. Additional protein consumption results in a significantly lower body weight regain after weight loss, due to body composition, satiety, thermogenesis, and energy inefficiency, while the metabolic profile improves. Implications from these findings are: for practice, recommendations for increasing the percentage of energy from protein while reducing energy intake; for clinical research, assessment of the paradox of increasing the percentage energy from a highly satiating macronutrient; of the potential roles of protein in a negative and positive energy balance; assessment of possibilities of replacing dietary protein by effective amino acids or peptides that may show a similar impact on body weight regulation.

Protein supplementation in conjunction with resistance training has been shown to promote an increase in muscle size and strength.

Andersen LL, Tufekovic G, Zebis MK, et al.

The effect of resistance training combined with timed ingestion of protein on muscle fiber size and strength.

Metabolism. 2005 Feb;54(2):151-6

Acute muscle protein metabolism is modulated not only by resistance exercise but also by amino acids. However, less is known about the long-term hypertrophic effect of protein supplementation in combination with resistance training. The present study was designed to compare the effect of 14 weeks of resistance training combined with timed ingestion of isoenergetic protein vs carbohydrate supplementation on muscle fiber hypertrophy and mechanical muscle performance. Supplementation was administered before and immediately after each training bout and, in addition, in the morning on nontraining days. Muscle biopsy specimens were obtained from the vastus lateralis muscle and analyzed for muscle fiber cross-sectional area. Squat jump and countermovement jump were performed on a force platform to determine vertical jump height. Peak torque during slow (30 degrees s-1) and fast (240 degrees s-1) concentric and eccentric contractions of the knee extensor muscle was measured in an isokinetic dynamometer. After 14 weeks of resistance training, the protein group showed hypertrophy of type I (18% +/- 5%; P < .01) and type II (26% +/- 5%; P < .01) muscle fibers, whereas no change above baseline occurred in the carbohydrate group. Squat jump height increased only in the protein group, whereas countermovement jump height and peak torque during slow isokinetic muscle contraction increased similarly in both groups. In conclusion, a minor advantage of protein supplementation over carbohydrate supplementation during resistance training on mechanical muscle function was found. However, the present results may have relevance for individuals who are particularly interested in gaining muscle size.

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