Amino acids are the basic building blocks of protein and can be obtained in an almost endless variety of supplemental forms, including capsules, tablets, bars, and powders. Some available products provide a food like mixture of all 20 nutritionally important amino acids, while other products focus on the specific characteristics of isolated amino acids. The evidence for the health and performance benefits of isolated amino acids is mixed at best. Only in limited circumstances do these supplements represent a valuable approach for athletes. The reader is referred to separate entries in this chapter providing scientific evidence suggesting that an isolated amino acid supplement may be useful for promoting health or performance (i.e., BCAAs, carnitine, glutamine, fi-hydroxy-fi-methylbutyrate [HMB], etc.).

Protein (Casein, Whey, Soy, Collagen, Colostrum)

Discussions of the value of protein supplements have become increasingly complicated in the last several years. The primary cause of debate is not the question of whether athletes require greater dietary protein intakes compared with their sedentary counterparts (the consensus suggests that they do) but rather the explosion in marketing of various forms of protein fractions like casein, whey, soy, colostrum, collagen, and others. The protein debate has slowly changed from “How much?” to “Which is best?” with no shortage of opinions and isolated studies but no clear consensus to guide decision making.

The evidence is strong that protein needs are elevated by exercise training, infection, and other periods of acute and chronic stress. Some of the best evidence comes from studies of competitive athletes, in whom protein needs are nearly doubled during periods of intense training and competition. Athletes competing in power or strength sports probably require about 1.6 g of protein per kilogram of body weight, and endurance athletes may need about 1.3 g/kg.

Undeniably, protein is a vitally important nutrient for general health and hundreds of specific functions in the body. The recommended dietary allowance (RDA) for protein is 0.8 g/kg of body weight for adults (0.36 g/ Ib), with growing children, adolescents, and both power and endurance athletes needing slightly more. By RDA standards, an adult weighing 70 kg (154 Ib) needs 56 g/day (about the amount provided in 8 oz of lean meat).

In most cases, the scientific evidence for a performance-enhancing effect of amino acids and/or protein comes from studies of using protein supplements to ensure adequate dietary protein intake. In a limited number of examples, isolated amino acid supplements provide additional performance and/or health effects, such as those noted for branched-chain amino acids for delaying fatigue, HMB and glutamine for inhibiting muscle loss, arginine for promoting blood flow, and cyst-eine for increasing cellular glutathione levels. In most other cases in which isolated amino acids have been used as dietary supplements, however, benefits in health and performance have been disappointing.

Protein is one of the primary nutrients involved in the growth, development, and repair of virtually all tissues in the body. Aside from simpiy ensuring adequate dietary protein requirements, supplemental protein can also be beneficial following strenuous exercise (by enhancing repair and regeneration of damaged tissues) and as a weight loss aid (because of the low glycemic index and heightened sense of satiety provided by a protein meal compared with meals higher in carbohydrates).

Author Bio: Georgiy Kharchenko with American Weight Loss Group LLC: Fitness Trainer, Ephedra Products, Natural Weight Loss Pills, Phentramin D Tablets

Category: Medicines and Remedies
Keywords: weight loss supplements, natural weight loss pills, dietary supplements, phentramin d