Protein supplementation – source & timing

Proteins are molecules that consist of one or more chains of amino acids. They are a structural component of muscle and other tissues in the body [5]. Protein is an important component of every cell in the body (body uses it to build and repair tissues, enzymes, hormones, and other body chemicals; is an important building block of bones, muscles, cartilage, skin, and blood; nails and hair are mostly made of it,..). [16]

Whether you are a competitive weightlifter, bodybuilder or you just want to look your best, you would surely benefit from knowing the ideal nutritional intake protocol needed to maximize muscle hypertrophy and strength. Type, timing and amount of protein intake are essential to meet strength-training goals. Clinical trials are showing that taking protein (especially whey) in combination with strength training improves athletic performance, increases lean body mass, strength, and muscle size [1-8].

How Much Should You Take?

A number of investigations involving strength and endurance athletes have shown that exercise increases the protein and amino acid need [1]. For endurance athletes, exercise can increase the need for protein by 50 to 100%. The need for protein in strength athletes is less clear, however, excess intake may promote muscle development [1]. Many studies are showing that for maximal muscle hypertrophy to occur, bodybuilders need to ingest from 1.2 to 2.0 grams of protein per kilogram of body weight daily.[1-3] The recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram of body weight which meets the needs of the majority of all healthy adults not involved in weightlifting.[4]

Which Protein Source is the Best?

So, the evidence is clear that athletes do benefit from increased protein intake. The focus then becomes on what type of protein to take. There are numerous sources available to the consumer. However, there are three sources of dairy protein (bovine milk, casein and whey) typically used in studies of muscle hypertrophy and strength. Its quality is often measured in biological value which indicates how efficiently the body makes use of them. Biological value measures protein quality by calculating the nitrogen used for tissue formation divided by the nitrogen absorbed from food [5].

Biological value rankings:

• Whey – 104,
• Bovine milk – 91,
• Casein – 77,
• Soy protein – 74.

Pic. 1 – Scoop of a whey powder.

Whey has the highest biological value, thus being superior to both milk and casein. Whey is the liquid part of milk that remains following the process of cheese manufacturing [5]. Whey proteins are then separated and purified [5]. Whey protein contains higher essential amino acid (EAA) concentrations than other protein sources [12] and has a fast absorption rate [13]. There are three main techniques to purify whey protein and each yield s a different whey form (whey powder, whey concentrate, and whey isolate). Compared to whey isolates whey concentrate actually contains more biologically active components [5]. Whey Protein Isolate is the purest source of protein (90% or higher) [5]. Although isolate is the purest form, the manufacturing process often breaks down their structure and loses peptide bonds which reduces the effectiveness of the protein [5].

Casein forms a gel or cloth in the stomach which results in sustained release of amino acids. Like whey, casein is a complete protein, meaning they both contain a complete set of EAA [5,6]. Casein also contains the minerals calcium and phosphorous. Compared to whey, the plasma appearance of dietary amino acids after casein ingestion is slow, lower, and prolonged [6].

What is the Best Timing?

That is one of the most frequently asked questions and studies are showing that timing is a very important factor when it comes to protein ingestion especially in relation to exercise. Cribb et al. [7] assigned 23 male bodybuilders into two groups for a 10-week resistance weight-training. One group received supplement (40 g whey, 46 g glucose and 7 g creatine) before and after a workout, while other in the morning and evening. There were significant differences in body composition in the before and after a workout supplemented group. This group also experienced increased lean body mass and decreased body fat and significantly greater gains compared to “morning and evening” group.

Hoffman et al. [8] supplemented with protein only. The study concluded, after 10 weeks of training, that supplementation pre/post each workout resulted in greater improvements in 1RM strength and body composition compared to the group who consumed supplement in the morning and evening.

One study also showed that adding protein to your breakfast along with a high fibre grain keeps you full for longer which can help you eat less throughout the day and aid you in meeting your weight loss goals [9].

Nutrients with Synergetic Effects

Creatine

Creatine monohydrate and Whey Protein are the two supplements commonly used by athletes in order to promote muscle hypertrophy and strength gains during exercise [11]. The common strategy among bodybuilders is a chronic use of creatine monohydrate in order to increase muscle strength and lean body mass [14]. The effectiveness of creatine monohydrate is highly dependent on its accumulation in the muscle [15].

Cribb, Paul J., et al. [11] examined the effects of combining creatine with carbohydrates and with whey during resistance-training in comparison to whey protein and carbohydrates alone, on strength, body composition and hypertrophy. Twenty-six male bodybuilders were divided into 4 groups [7 = CH (carbohydrates), 5 = WP (whey protein), 8 = CrCH (creatine + carbohydrates) and 6 = CrWP (creatine + whey protein)]. The most significant gains were in CrCH (+3.7 kg), CrWP (+3.4 kg) and WP (+2,4 kg) groups. These groups also demonstrated a greater increase in strength in each exercise compared to the CH group.

The most important finding of this study was that CrCH, WP and CrWP groups resulted in greater hypertrophy response compared to carbohydrate and protein only groups. [11]

Side Effects and Concerns

One of the major concerns about protein consumption is associated with renal (kidney) function. Proteins are said to cause renal damage to healthy humans. In a healthy population, there does not appear to be any adverse effects of a high protein diet. Poortmans et al. [10] concluded that protein intake under 2.8 g/kg does not impair renal function in well-trained athletes. If an individual has an existing kidney disease protein intake should be limited to approximately half of the normal RDA level for daily intake (0.8 grams per kilogram).

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References

1. Lemon, P. W., and D. N. Proctor. “P intake and athletic performance.” Sports Med 12.5 (1991): 313-325.
2. Phillips, Stuart M. “P requirements and supplementation in strength sports.” Nutrition 20.7 (2004): 689-695.
3. Lemon, Peter WR. “Beyond the zone: p needs of active individuals.” Journal of the American College of Nutrition 19.suppl 5 (2000): 513S-521S.
4. Gropper, Sareen S., and Jack L. Smith. Advanced nutrition and human metabolism. Wadsworth Publishing Company, 2012.
5. Hoffman, Jay R., and Michael J. Falvo. “P – Which is best.” Journal of Sports Science and Medicine 3.3 (2004): 118-30.
6. Boirie, Yves, et al. “Slow and fast dietary proteins differently modulate postprandial protein accretion.” Proceedings of the National Academy of Sciences 94.26 (1997): 14930-14935.
7. Cribb, Paul J., and Alan Hayes. “Effects of Supplement-Timing and Resistance Exercise on Skeletal Muscle Hypertrophy.” Medicine & Science in Sports & Exercise 38.11 (2006): 1918-1925.
8. Hoffman, Jay R., et al. “Effect of a proprietary p supplement on recovery indices following resistance exercise in strength/power athletes.” Amino acids 38.3 (2010): 771-778.
9. Michael W. Smith, MD. Retrieved from WebMD.com at 24. May 2013
10. Poortmans, Jacques R., and Olivier Dellalieux. “Do regular high p diets have potential health risks on kidney function in athletes?.” International Journal of Sport Nutrition 10.1 (2000): 28-38.
11. Cribb, Paul J., et al. “Effects of whey isolate, creatine and resistance training on muscle hypertrophy.” Medicine & Science in Sports & Exercise 39.2 (2007): 298-307.
12. Bucci, Luke R., and Lisa Unlu. “Proteins and amino acid supplements in exercise and sport.” Energy-Yielding Macronutrients and Energy Metabolism in Sports Nutrition (2000): 191-212.
13. Dangin, Martial, et al. “The rate of P digestion affects protein gain differently during aging in humans.” The Journal of physiology 549.2 (2004): 635-644.
14. Rawson, ERIC S., and JEFF S. Volek. “Effects of creatine supplementation and resistance training on muscle strength and weightlifting performance.” Journal of Strength and Conditioning Research 17.4 (2003): 822-831.
15. Hultman, E., et al. “Muscle creatine loading in men.” Journal of Applied Physiology 81.1 (1996): 232-237.
16. Neil Osterweil “The Benefits of Protein”