Anabolic Agents

The most frequently and widely used category of ergogenic aids is those with supposed anabolic effects; that is, they mimic the benefits of steroids (in a legal manner). Creatine is the most widely used supplement taken by both recreational and professional athletes. Creatine is synthesized in the kidneys, pancreas, and liver from amino acid precursors (methionine, arginine, and glycine), and is also found in meat, fish, and poultry. The ergogenic effect of supplemental creatine is attributed to its ability to increase tissue creatine levels beyond what the body can synthesize on its own, resulting in increased work capacity during intense activity requiring maximal or near maximal effort. It can also expedite the recovery rate following exercise. These benefits are most likely seen with a regimen of 20 to 25 grams of creatine over five to seven days, divided into four- or five-gram doses (this is called the loading phase). Creatine levels will fall to presupplementation levels six weeks later. For optimal effect, each dose of creatine should be consumed with a carbohydrate and without caffeine, which can counteract the ergogenic effect. Muscle hypertrophy and fluid retention can occur during the loading phase, causing a weight gain of four to seven pounds. This increase may be advantageous for the strength athlete, but less so for an athlete who relies on speed. Short-term studies have not shown an increase in muscle strains, cramps, or pulls with crea-tine, but it is critical for the athlete to maintain optimal hydration. There are some concerns with product contamination, as creatine supplements could be contaminated with herbs, or even with other anabolic agents not listed on the label.

Other anabolic agents include HMB (beta-hydroxy beta-methylbutyrate), which, in clinical studies, has resulted in an increase in muscle mass. The number of studies has been quite small, however. Boron is a trace mineral involved in cellular functions, but it does not increase testosterone levels as some claims would suggest. It can suppress appetite and impair digestion in doses higher than 50 mg per day. Yohimbe is a supplement derived from the tree bark of a South American plant that confers a stimulant effect, not an anabolic effect. Ingestion of this product can cause dizziness, nervousness, headaches, nausea, vomiting, and an elevated blood pressure. It can also interact with blood-pressure medication and increase the toxicity of

Mark McGwire astounded baseball fans when he hit 70 home runs in 1998. But his use of legal performance-enhancing supplements, such as androstenedione, raised tough questions for athletes and trainers. [AP/Wide World Photos. Reproduced by permission.]

psychotherapeutic medications, and it may be harmful to the kidneys. Chromium is an essential mineral involved in blood glucose control. It can be taken in a dosage of between 50 and 300 micrograms per day, but it does not have any anabolic effects.

Other supposed anabolic agents include dehydroepiandrosterone (DHEA), androstenedione, and Tribulus terrestris (tribestan). All of these are banned by the U.S. Olympic Committee, the National Collegiate Athletic Association (NCAA), the National Football League, and the American Tennis Federation. Studies have demonstrated the ineffectiveness of an-drostenedione as an anabolic substance or strength enhancer, but they have demonstrated potentially worrisome side effects, including a decrease in serum HDL level and an increase in serum estrone and estradiol, which increases the likelihood of gynecomastia (breast enlargement). In addition, several laboratory tests have shown that the amount of actual product in these supplements can vary dramatically, and some are contaminated with nandrolone, an anabolic steroid that can cause a positive result in a drug test.

glucose: a simple sugar; the most commonly used fuel in cells serum: non-cellular portion of the blood

HDL: high density lipoprotein, a blood protein that carries cholesterol estradiol: female hormone; a type of estrogen nandrolone: hormone related to testosterone vitamin: necessary complex nutrient used to aid enzymes or other metabolic processes in the cell mineral: an inorganic (non-carbon-containing) element, ion, or compound gastrointestinal: related to the stomach and intestines immune system: the set of organs and cells, including white blood cells, that protect the body from infection nervous system: the brain, spinal cord, and nerves that extend throughout the body fatigue: tiredness glycogen: storage form of sugar anxiety: nervousness contraindicated: not recommended heart disease: any disorder of the heart or its blood supply, including heart attack, atherosclerosis, and coronary artery disease hypertension: high blood pressure diabetes: inability to regulate level of sugar in the blood

Protein Supplements. Protein is essential for muscle growth and development, but the maximum usable amount of protein is one gram per pound of body weight. Protein powders contain large quantities of protein, plus large doses of vitamins, minerals, and herbs. Amino acid supplementation has been associated with gastrointestinal side effects, such as nausea, diarrhea, or vomiting, that may negate any potential ergogenic benefits. In addition, selective amino acid supplementation is a very inefficient way to provide protein to the body and can create an amino-acid imbalance.

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