Nutritional Supplements To Enhance Performance Articles & Resources

Nutritional supplements, which enhance performance and the results of exercise, are a popular alternative to anabolic steroids. When used responsibly, they are safer and provide a more natural approach to improving the body's response to exercise. Most supplements used to enhance athletic performance are sanctioned by serious athletes and are legal in the competitive arena. However, any anabolic supplement should be used with caution. Women of all ages and men under the age of 18 are especially vulnerable to risk factors associated with rapid or extensive anabolism. Some of the supplements discussed are contraindicated for both groups.

Common nutritional supplements

Androstenedione: Androstenedione is an androgenic precursor of testosterone, secreted by the adrenals, testes and (in small amounts) ovaries. In the presence of androstenedione, DHEA (dehydroepiandrosterone) is converted to testosterone. Supplementing with androstenedione is thought to enhance the body's natural production of testosterone, subsequently improving muscle strength and size. Endurance training has a naturally stimulating effect on androstenedione and testosterone, pointing to the importance of these androgens in sustaining energy during strenuous [.3]. Supplementing with androstenedione may also help to minimize the post exercise decline of plasma androgen levels and therefore decrease recovery [.4].

Androstenedione raises testosterone levels within about two hours, so it is typically taken approximately one hour before exercise. A dose of 50 mg taken 2 to 3 times per day is a suggested safe and effective dose range. It is metabolized quickly, lasting approximately three hours in the bloodstream. Doses should not exceed 200 mg per day. Androstenedione should not be taken by women and is contraindicated in prostatic hyperplasia, diabetes, heart disease and any hormonal abnormalities. This agent is somewhat controversial because it is banned from some professional and amateur sports.

Creatine monohydrate: Creatine is a compound formed in the body from the amino acids arginine, glycine and methionine. Creatine combines readily with phosphate to form phosphocreatine. Phosphocreatine is present in muscle tissue, where it is available as an immediate energy source. Phosphocreatine regenerates ATP in skeletal muscle and energizes muscle contractions, thus playing important roles in both energy preservation and [.5].

In several studies, supplementing with creatine reportedly increased intramuscular phosphocreatine stores, enhanced exercise performance, increased muscle mass and shortened recovery periods after [.6-9]. In one study, a four-day loading dose of 20 grams per day, followed by 10 weeks of a low dose (5 grams per day) of creatine supplementation resulted in a 20 percent to 25 percent increase in muscle strength and a 60 percent increase in fat-free body mass among female test [.10]. Another study demonstrated that after ingesting 20 grams per day of creatine for five days, male subjects increased isokinetic work performance by 4 percent, while cumulative loss of ATP was percent less than before creatine [.11]. During many of the clinical trials conducted with creatine, there appeared to be no harmful side effects associated with recommended loading or maintenance doses of creatine. Suggested loading dose is 5 grams four times a day for one week, followed by a maintenance dose of 5 grams to 10 grams daily. Expert opinion varies on its use, but some recommend cycling creatine for six weeks on, four weeks off.

Whey protein: Whey protein is a high-quality, ion exchange protein derived from milk. Ion exchange is the process by which the whey is removed from the whole protein by electrostatic separation, yielding a highly concentrated and bioavailable protein formula. During exercise, the body's need for protein is increased. Protein is needed for tissue repair, muscle growth and gluconeogenesis. Nitrogen, a byproduct of protein catabolism, is a measurement of the body's protein equilibrium, or nitrogen balance. In a catabolic state, a negative nitrogen balance is the result of inadequate protein in the diet. Anabolic conditions require more protein in the diet than just the amount used for basic energy requirements. A positive nitrogen balance is ideal for increasing muscle size and strength.

Studies have reported an increase in nitrogen retention, improved protein synthesis, increased weight gain and less total body nitrogen loss in rats fed oligopeptide whey [.2]. Amino acids, the building blocks of proteins, are necessary for proper immune function. Whey protein provides a complete amino acid profile for optimum immune function. The suggested protein intake for serious athletes is 1 gram per pound of body weight. For optimal uptake of amino acids into muscle, insulin regulation should be optimized.

Glutamine: L-Glutamine is an amino acid abundant in muscle tissue. It plays a vital role in protein metabolism and muscle recovery. L-Glutamine is also critical in immune and digestive functions. When glutamine stores in the body are low, muscles compete with immune and digestive functions for the amino acid. Under prolonged catabolic conditions, such as strenuous exercise, glutamine is used for gluconeogenesis. The availability of glutamine to leucocytes may influence immune [.13]. It is therefore necessary to maintain glutamine homeostasis in athletes undergoing intense, prolonged training.

One study measured the relationship between exhaustive exercise, plasma glutamine levels and opportunistic infection. Seven days after exercise, infection levels were reportedly highest among marathon and ultra marathon runners, whose plasma glutamine levels were decreased by 20 [.4]. Supplementing with glutamine after exercise appeared to have a beneficial effect on post-exercise opportunistic [.15]. The recommended loading dose of glutamine is 10 grams to 15 grams per day, followed by a maintenance dose of 2 grams to 6 grams per day.

Cordyceps sinensis: Cordyceps sinensis, or caterpillar fungus, is a fungus cultivated on caterpillar larvae and belongs to a species that represents only 2 percent of the world's fungi. Cordyceps' first documented use dates back to 1700 BC. The active components in C. sinensis include hemicellulose, polysaccharides, nucleosides and triterpenoids. It has been used in traditional Chinese medicine as a general health tonic and to treat circulatory, sexual, immune, respiratory and nervous conditions. It has been clinically demonstrated to decrease fatigue, increase energy and enhance endurance.

A recent literature review cites the main activities of cordyceps as oxygen free radical scavenger, hypolipidemic, anti-atherosclerotic and endocrine and sexual function [.16]. The use of cordyceps among Chinese athletes is thought to enhance energy levels and performance by increasing ATP production in the mitochondria. It is also thought to increase blood supply to the coronary arteries, decrease peripheral vascular resistance and increase total blood volume. Cordyceps may also enhance testicular production of testosterone via corticosterone production by adrenal cells and raise serum adrenaline [.17]. The recommended dose for C. sinensis is 1,100 mg 2 to 3 times daily.