Athlete nutrition

Amphetamines, anabolic steroids, androstenediol, androstenedione, athlete nutrition, athletic performance, blood doping, caffeine, carbohydrate loading, carnitine, chromium, creatine, DHEA, dehydroepiandrosterone, ephedrine, ergogenic aids, exercise, fitness, hormones, human growth hormone, leucine, multivitamins, phosphates, protein, sports performance, steroids, vitamins, yohimbine.

Sports supplements, also known as ergogenic aids, are products used to enhance athletic performance. They may come in different forms including vitamins, synthetic (man-made) drugs, and hormones, most of which are available over the counter without a prescription.

The word ergogenic is derived from the Greek word ergon, which means to increase work or potential for work. Throughout history, people have sought foods and substances that purportedly improve physical strength. Medieval doctors held the belief that warriors should eat human hearts to increase bravery, brains to increase intelligence, and pituitary extracts to enhance muscle strength. It has been reported that Greek Olympians from 300 BC used mushrooms to enhance performance, Dutch swimmers in 1865 used caffeine as an ergogenic aid, Belgian athletes in the late 19th Century dipped sugar cubes in ether for endurance, and ancient Aztec athletes as well as marathon runners today have used a cactus-based stimulant to enhance performance.

Some athletes may be misled by strong, false claims of some products currently on the market. To deter false claims, beginning in July 1995, the U.S. Food and Drug Administration (FDA) has mandated that all the nutrients in dietary supplements be listed on product labels.

Some herbal products and nutritional supplements may contain banned substances, such as ephedrine or androstendione, and should be avoided. Many substances are also banned by the National Collegiate Athletic Association (NCAA), and student athletes who use them may lose their eligibility to compete.

People may take supplements to develop more muscle mass, increase strength, build stamina or lose weight. Athletes have used supplements to improve performance through increased endurance, enhance muscular strength/power, recover from heavy workouts, or to prevent illness from sport-related exertion. Compounds such as bee pollen, caffeine, glycine, carnitine, lecithin, brewer's yeast, and gelatin are claimed to improve strength and endurance. Dietary supplements such as these are widely available through many commercial sources including health food stores, grocery stores, pharmacies, and by mail. Current available scientific research has failed to substantiate many of these claims.

There are a number of sports supplements available on the market. Below is a list of some of the more popularly used supplements. For a more detailed look at individual herbs or supplements, please see the Herbs and Supplements Database.

Amino acids and other nitrogen containing substances: Amino acids are the basic building blocks of muscle. Arginine, lysine, and ornithine are popular amino acids for strength-training. Studies have revealed that taking arginine and ornithine while carrying out a strength training program may reduce body fat, increase LBM (lean body mass), and increase strength. However, studies using experienced weightlifters and alternative experimental designs have had conflicting results. One study found no significant effect of oral arginine supplementation on peak muscle torque or muscular endurance. Another study found that arginine and lysine supplementation had no effect on body composition or strength. Another study examining all 20 standard amino acids found they had no effect on lifting performance.

Anabolic (tissue-building) steroids: Anabolic steroids are hormones that may help the body build muscle tissue and increase muscle mass. Steroids are similar to the male hormone testosterone, which is produced naturally in larger amounts in males and smaller amounts in females. When a person takes steroids, the body's muscle tissue is stimulated to grow, producing larger and stronger muscles. Steroids may have serious side effects that may include high blood pressure, heart disease, liver damage, cancer, urinary and bowel complications, strokes, blood clots, sleep disorders, baldness, and severe acne. Men who take steroids may suffer from infertility, breast and nipple enlargement, and erectile dysfunction. Women may develop a deeper voice, smaller breasts, menstrual problems, and an increase in facial and body hair. Steroids may also cause severe mood swings, aggressive behavior, irritability, or depressive or suicidal thoughts. Injecting steroids with needles carries an additional risk for HIV or hepatitis infection.

Androstenedione and DHEA (dehydroepiandrosterone): Androstenedione and DHEA (dehydroepiandrosterone), popular nutritional supplements, are prohormones or natural steroids that can be broken down into testosterone. There is sufficient evidence supporting the use of DHEA in the treatment of adrenal insufficiency. However, preliminary evidence, as well as various controlled trials, suggests that DHEA likely offers no benefit for increased muscle strength. No studies on the long-term effects of DHEA have been conducted. Well designed clinical trials with appropriate endpoints are required before recommendations can be made in this field. Preliminary trials in patients with myotonic dystrophy suggests possible efficacy of DHEA. More research is needed in this area.

DHEA can cause higher than normal levels of androgens and estrogens in the body, and theoretically it may increase the risk of prostate, breast, ovarian, and other hormone-sensitive cancers. Androstenedione and DHEA may cause hormone imbalances and increase the risk for testicular cancer, infertility, stroke, and heart disease. Also, like anabolic steroids, the use of androstenedione before the typical adolescent growth spurt period may prevent a teen from reaching full adult height.

Antioxidant vitamins: Although regular exercise produces many positive health benefits, it may also increase production of free radicals. Intense or prolonged exercise may cause radical-mediated injury to skeletal muscles, particularly in untrained individuals. Free radicals are damaging molecules that are produced during normal metabolism. Further, radicals may contribute to muscular fatigue during endurance events. Cells contain antioxidants (molecules that eliminate free radicals) to reduce the risk of radical-mediated injury. Non-enzymatic antioxidants include vitamins E and C, which are included in many foods, and may also be obtained through dietary supplements. Vitamin E is thought to protect cell membranes from radical damage. Vitamin C works with vitamin E to protect fatty substances and proteins in the cell from radical damage. There is little, well-documented scientific support for antioxidant supplementation in athletes who consume a well-balanced diet that is rich in fruits and vegetables. Further, over-consumption of antioxidants may have potentially harmful side effects because high levels of some antioxidants may be toxic.

Arnica: Arnica (Arnica montana) has been used to treat exercise-induced delayed onset muscle soreness and is commonly used in topically applied herbal ointments and oils as an anti-inflammatory and analgesic agent for aches, bruises, and sprains on unbroken skin. Highly diluted homeopathic preparations are considered safe and are widely used for the treatment of injuries. However, full doses of arnica may be toxic when ingested orally, often leading to severe irritation of mucous membranes and the gastrointestinal tract. Arnica may also be cardiotoxic, resulting in high blood pressure. Many clinical trials have been challenged with inconsistent testing methodologies, which have not found statistically significant efficacy between herbal or homeopathic forms of arnica and placebo.

Astragalus (Astragalus membranaceus): Astragalus, also known as known as huang chi, huang qi, or milk vetch, may be used for immune enhancement and maintaining overall health. Experimentally, fractions of astragalus have been shown to have immuno-stimulant and anti-oxidant properties in vitro and in vivo, which in turn exert protective cellular effects in organs such as the liver, lung, kidneys, and the cardiovascular system.

Boron: There is preliminary negative evidence for the use of boron for improving performance in bodybuilding by increasing testosterone. Although boron is suggested to raise testosterone levels in early human research, total lean body mass has not been affected by boron supplementation in bodybuilders. Additional research is necessary before a firm conclusion can be drawn. There is conflicting evidence to support the use of boron in hormonal regulation and cognitive function. Excessive use of boron has lead to fatal poisonings. Boron is easily absorbed and subsequently eliminated primarily through the kidney and should therefore be used cautiously in patients with renal insufficiency.

Carnitine: Carnitine has been theorized to be ergogenic for aerobic endurance athletes. It is found naturally in food, particularly in meats, but it is also synthesized in the body. Carnitine has been advertised to strength athletes as a means to facilitate loss of body fat, but no well-documented research supports this claim.

Cayenne: Cayenne (Capsicum frutescens, Capsicum annuum), also called known as capsicum, red pepper, hot pepper, African chilies, and paprika, is used by athletes because of its potential to relieve musculoskeletal pain. The active component, capsaicin, may have a pain-relieving effect based on its ability to interfere with sensory nerve signaling in the skin. However, higher quality studies are needed before a recommendation can be made. Orally, cayenne may cause many gastrointestinal side effects, including abdominal discomfort and nausea. Topically, it may cause burning and stinging. Cayenne may interact with several medications, including theophylline, ACE inhibitors, sedatives, antihypertensives, and acetaminophen.

Choline: Choline is a precursor to acetylcholine, a chemical used to transfer nerve impulses. Therefore, choline is believed to have neurological effects. Choline is a product of the breakdown of the muscle relaxant succinylcholine, which is used extensively in anesthesia. Theoretically, choline may exhibit similar muscle relaxing effects. There is a lack of sufficient evidence for the use of choline for altering body composition, specifically, changing body fat and lean muscle.

Chromium: Chromium is currently marketed as an anabolic aid for athletes, primarily in the form of chromium picolinate. Chromium has been studied for its ability to improve lean body mass (reducing fat and increasing muscle), but results have not been consistent. More studies are needed before a recommendation can be made.

Conjugated Linoleic Acid (CLA): CLA has been shown to lower adiposity in animals and sometimes in humans, but human studies have not included rigorous controls for diet and exercise. The mechanism of action is unknown, but CLA is theorized to reduce lipoprotein lipase activity, reduce intracellular triglycerides, and enhance glycerol release from adipose tissue. CLA comes in two isomers, the 9,11 isomer, which appears responsible for improving muscle growth, and the 10,12 isomer, which primarily prevents lipogenesis (storage of fat in tissue). Most supplements sold in stores contain a 50-50 mix of both isomers. Many studies on CLA in humans show a tendency for reduced body fat, particularly abdominal fat, changes in serum total lipids, and decreased whole body glucose uptake. Higher quality studies are needed before a firm recommendation can be made. Dietary CLA supplementation does not seem to have any adverse effects.

Cordyceps (Cordyceps sinensis, Sphaeria sinensis): Cordyceps, also known as caterpillar fungus, dong chong xai cao, semitake, and hsia ts'ao tung ch'ung, is a Chinese mushroom that may be used for many conditions including fatigue, respiratory disorders, sexual dysfunction, and for enhancing the immune system and improving athletic performance. There is little well-documented evidence that cordyceps may influence athletic performance. Cordyceps may reduce blood glucose levels, so blood glucose monitoring may be indicated for use in athletes. In addition, cordyceps may interact with hypoglycemic medications.

Creatine: In the 1970s, Soviet scientists reported that oral creatine supplements may improve athletic performance during brief, intense activities such as sprints. Creatine gained popularity in the 1990s as a "natural" way to enhance athletic performance and build lean body mass. It was reported that skeletal muscle creatine content increases with oral creatine supplementation, although the response is variable. Factors that may account for this variation are carbohydrate intake, physical activity, training status, and muscle fiber type. The finding that carbohydrates enhance muscle creatine uptake increased the market for creatine multi-ingredient sports drinks. It has been suggested that creatine may help improve athletic performance or endurance by increasing time to fatigue, possibly by shortening muscle recovery periods. However, the results of research evaluating this claim are mixed. Although many experts believe that creatine may be useful for high-intensity, short-duration exercise, it has not been demonstrated effective in endurance sports. Due to methodological problems with available studies, a firm conclusion cannot be reached.

Devil's Claw: Devil's claw (Harpagophytum procumbens), also known as grapple plant, harpagophytum, and wood spider, is a perennial herb that may be used as a pain reliever in athletes. Currently, the major clinical uses of devil's claw are as an anti-inflammatory or analgesic in joint diseases, back pain, and headache. Published studies in animals and humans have resulted in widespread publicity and use of standardized devil's claw as a mild analgesic for joint pain in Europe. In vitro and animal experiments suggest that devil's claw exhibits anti-inflammatory properties, possibly via COX-2 inhibition.

Echinacea: Echinacea (Echinacea purpurea, Echinacea angustifolia, Echinacea pallida) is a popular herb used in oral preparations in Europe and the United States for the prevention and treatment of upper respiratory tract infections (URI) such as the common cold and to enhance the immune system. Currently, evidence for use of Echinacea as a remedy to prevent and treat URI remains indeterminate in adults. In children, Echinacea cannot be recommended due to an excess of rash seen with Echinacea versus placebo in one study and a lack of demonstrated benefits in a well-designed trial. The German Commission E discourages the use of Echinacea in patients with autoimmune diseases, but this warning is based on theoretical considerations rather than human data.

Elderberry (Sambucus nigra): In recent years, elderberry supplements, juices, and syrups have become popular for their flavonoid (chemical compounds with antioxidant effects) content. In athletes, elderberry may be used to manage common symptoms of colds, influenza, and fever.

Ephedra: Ephedra (Ma huang or Ephedra sinica) has been used in traditional Chinese medicine (TCM) for over 5,000 years for asthmatic respiratory disorders. In athletes, ephedra has been popularly used as a CNS stimulant (to enhance alertness) and cardiovascular stimulant. Ephedrine can also be used as a starting material for the illegal manufacture of "speed" or methamphetamine. Some athletes use ephedra to boost their performance; however, in at least one case, a prestigious athlete was eliminated from competition because the product he used included norpseudoephedrine, which is banned by the International Olympic Committee. On February 6th, 2004, the U.S. Food and Drug Administration (FDA) issued a final rule prohibiting the sale of dietary supplements containing ephedrine alkaloids (ephedra) because such supplements present an unreasonable risk of illness or injury. The rule became effective 60 days from the date of publication. Because of the variable concentrations of ephedrine found in commercial preparations and numerous reports of serious adverse effects (particularly when combined with caffeine), ephedra is not considered to be a safe therapy for athletic performance.

Gamma oryzanol: Gamma oryzanol is a ferulic acid ester derived from rice bran oil. Both gamma oryzanol and ferulic acid products are advertised as substances that increase serum testosterone and HGH. Although gamma oryzanol may influence lipid metabolism, there is no well-documented evidence pertaining to its ergogenic effect in humans. Gamma oryzanol is a phytosterol, a plant-based compound that may compete with intestinal dietary cholesterol absorption, resulting in lower blood cholesterol levels.

Ginger: Ginger (Zingiber officinale) may be used to treat depressed appetite, colic, diarrhea, drug withdrawal symptoms, indigestion, motion sickness, nausea, vomiting, and other ailments. The rhizomes (underground stem) and stems of ginger have been used in traditional Chinese, Japanese, and Indian medicine since the 1500s. The oleoresin of ginger is often contained in digestive, antitussive, antiflatulent, laxative, and antacid compounds. There is supportive evidence from one randomized controlled trial and an open-label study that ginger reduces the severity and duration of chemotherapy-induced nausea/emesis. Effects appear to be additive with use of prochlorperazine (Compazine?). The optimal dose remains unclear. Ginger's effects on other types of nausea/emesis, such as postoperative nausea or motion sickness remain indeterminate. Ginger is used orally, topically, and intramuscularly for a wide array of other conditions, without scientific evidence of benefit. Ginger may inhibit platelet aggregation and decrease platelet thromboxane production, thus theoretically increasing the risk of bleeding. Ginger has been listed in the in the U.S. Pharmacopoeia (USP) and the National Formulary as a carminative (anti-flatus agent), aromatic, and stimulant. Ginger is widely used as a seasoning or fragrance in foods, beverages, soaps, candles, and cosmetics. There is generally <0.5% ginger in average baked goods.

Ginseng: Ginseng is widely marketed and commonly used by athletes as an exercise performance and stamina enhancing supplement. However, it remains unclear if ginseng taken orally significantly affects exercise performance. Numerous studies have been published in this area with mixed results. Most research has not been well designed or reported and cannot be considered reliable. The term ginseng refers to several species of the genus Panax. The two most commonly used species are Asian ginseng (Panax ginseng C.A. Meyer), which is mostly extinct in its natural range but is still cultivated, and American ginseng (P. quinquefolius L.), which is both harvested from the wild and cultivated. Panax ginseng should not be confused with Siberian ginseng (Eleutherococcus senticosus). Siberian ginseng does not contain the ginsenosides that are present in the Panax species, which are believed to be active ingredients and have been studied scientifically.

Glandulars: Glandulars are extracts from various animal tissues or glands, such as the pituitary, thymus, and adrenal glands and the testes. Athletes have used glandulars in order to purportedly enhance function of the glands in the body from which they are derived. For example, orchic extract from the testes allegedly assists testosterone production. However, these glandular extracts are broken down during the digestive process and are inactive when absorbed as digested components.

Gotu kola: Athletes have used gotu kola (Centella asiatica, Hydrocotyle asiatica) to reduce skin inflammation, increase energy levels, and aid in recovery from injuries such as sprains and strains. There is currently insufficient high quality clinical evidence to support the use of gotu kola for athletic performance.

Guarana: Guarana (Paullinia cupana) is thought to have caffeine-like effects and may be found in many energy or fat loss supplements marketed to athletes. Guarana is also used to enhance athletic performance and to reduce fatigue. It is also used as an additive for soft drinks (e.g. Dark Dog Lemon?, Guts?, and Josta?). Derived from the seed and gum of the guarana tree, guarana is primarily marketed as an appetite suppressant, central nervous system stimulant, and athletic and energy enhancer. Guarana is thought to potentially interact with several types of supplements and medications, including caffeine-containing supplements, ephedra, monoamine oxidase inhibitors, adenosine, clozapine, lithium, oral contraceptives, and acetaminophen. Guarana is generally regarded as safe when not combined with other stimulatory agents, such as ephedra. There is insufficient high quality clinical research examining the effects of guarana used as a monotherapy (not in combination with other herbs or supplements).

Human growth hormone(hGH): Doctors may prescribe growth hormone for teens who have certain hormone or growth problems to help them develop normally. But growth hormone has also been abused by athletes to build muscle mass. Teen athletes who abuse growth hormone may have impaired development and altered hormone levels.

Inosine:Inosine is a molecule involved in the formation of purines such as adenine. Advertisements have suggested that inosine supplementation may enhance adenosine triphosphate (ATP) formation in muscle and thus be of value to strength athletes. However, there is no well-documented research to support this claim.

Lipids: Although dietary lipids may be used as a source of energy for strength-trained athletes attempting to gain weight, most lipid derivatives are advertised to provide beneficial effects on metabolic processes. Plant sterols, or phytosterols, are marketed because of their structural resemblance to testosterone.

Magnesium: Magnesium is an essential nutrient with multiple metabolic roles, including its involvement in protein synthesis and muscle contraction. Currently, there is no well-documented research supporting magnesium supplementation for strength-trained athletes, but more research appears to be warranted.

Medium chain triglycerides:Medium chain triglycerides (MCT) are water soluble fatty acids that can be absorbed and metabolized readily. Commercial brands are advertised as able to promote muscularity and to lower body fat, possibly because of their energy content and their thermic effect upon ingestion. MCT supplementation has been studied in relation to aerobic endurance exercise, and found to be ineffective, but no well-documented studies have revealed an ergogenic effect on muscularity or weight loss in strength-trained athletes.

Omega-3 fatty acids (O-3FA): Omega-3 fatty acids may be metabolized in the body to eicosanoids. Dietary sources of omega-3 fatty acids include fish oil and certain plant/nut oils. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), while some nuts (English walnuts) and vegetable oils (canola, soybean, flaxseed/linseed, olive) contain alpha-linolenic acid (ALA). There is evidence from multiple large-scale population (epidemiologic) studies and randomized controlled trials that intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements lowers triglycerides, reduces the risk of death, heart attack, dangerous abnormal heart rhythms, and strokes in people with known cardiovascular disease, slows the buildup of atherosclerotic plaques ("hardening of the arteries"), and lowers blood pressure slightly. However, high doses may have harmful effects, such as an increased risk of bleeding. Although similar benefits are proposed for alpha-linolenic acid, scientific evidence is less compelling and beneficial effects may be less pronounced.

Protein: The recommended dietary allowance (RDA) for protein, which will support normal growth and development in the average individual, is 0.8 g/kg body weight per day for individuals ages 19 and above, 0.9 g/kg for ages 15-18, and 1.0 g/kg for ages 11-14. However, athletes involved in intense strength training programs, particularly untrained individuals, may have significantly higher protein requirements than do sedentary individuals. To maintain or possibly increase muscle mass while strength training, some investigators have recommended approximately twice the current American and Canadian RDA. These additional energy and protein needs may be obtained easily from a balanced, healthful diet.

Rhodiola: Rhodiola (Rhodiola rosea), a popular plant in traditional medicine in Eastern Europe and Asia, may help resist physical, chemical, and biological stressors. Rhodiola has been claimed to stimulate the nervous system, decrease depression, enhance work performance, eliminate fatigue, and prevent high altitude sickness. It is also marketed to improve athletic performance. Also known as golden root or Arctic root, it has been widely studied in Russia and Scandinavia for more than 35 years.

Valerian: Valerian (Valeriana officinalis, Valerianae radix) is used orally as a sedative-hypnotic for insomnia, sleep disorders, and anxiety, for mood disorders such as depression and attention deficit-hyperactivity disorder (ADHD), and to lessen menstrual cramps, and aid muscle and joint pain. Valerian is widely used to treat insomnia and anxiety. Better effects have been noted in poor sleepers. Early evidence suggests that ongoing use may be more effective than acute (single-dose) use, with progressive effects over several weeks. However, most available studies have been methodologically weak and in most cases results have not been confirmed using objective sleep pattern data in a sleep laboratory or with validated measurement scales. Studies report that valerian is generally well tolerated for up to four to six weeks. However, rarely it may produce mild adverse effects (dizziness, hangover, headache).

Willow bark: Athletes may use willow bark (Salix alba), also known as white willow, black willow, purple osier, and bay willow, in place of aspirin to ease aches and pains. The main active component of willow bark extract is salicin, which is converted to acetylsalicylic acid in the intestine. It is used for many indications including fever, headaches, inflammation, osteoarthritis, influenza, and muscle pain.

Yohimbine: Yohimbine is a nitrogen-containing alkaloid extracted from the bark of the yohimbe tree(Pausinystalia yohimbe). The terms yohimbine, yohimbine hydrochloride, and yohimbe bark extract are related but not interchangeable. Yohimbine hydrochloride is a standardized form of yohimbine that is available as a prescription drug in the United States, and has been demonstrated in clinical trials to be effective in the treatment of erectile dysfunction. Yohimbine hydrochloride has also been used for the treatment of sexual side effects induced by antidepressants (SSRIs), female hyposexual disorder, as a pressor agent in autonomic failure, xerostomia, and as a probe for noradrenergic activity. In contrast, there is a paucity of clinical research utilizing yohimbe bark extract, which generally contains low concentrations of yohimbine (6% indole alkaloids, of which only 10-15% is yohimbine), and commercial preparations may or may not share the pharmacological and clinical effects of yohimbine hydrochloride. A 1995 chemical analysis of 26 commercial yohimbe products reported that most products contain virtually no yohimbine. Traditionally, yohimbe bark was used as an aphrodisiac and mild hallucinogen. However, all information related to its efficacy is folkloric, empirical and anecdotal, or extrapolated from studies of yohimbine hydrochloride. Most commercial sources of yohimbe bark extract do not state the level of yohimbine alkaloid content per dosage. Therefore, use of pure pharmaceutical-derived yohimbine hydrochloride is the only method of ingesting an exact amount of yohimbine. Given the pronounced pharmacological properties of yohimbine, the use of yohimbe bark products that do not specify indole alkaloid content is potentially dangerous.

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

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Nutrition for sports performance generally includes the following components: fluid intake and hydration, energy substrates (carbohydrate, protein and fat), vitamin and mineral balance, and pre-game and recovery meals.

Sports supplements come in many forms including pills, energy bars, drinks, powders, and gels.

Sports supplements may be taken before meals, as meal replacements, or in addition to a normal meal.

The frequency of sports supplement consumption varies among substances and is dependent on the reason for taking the supplement and the desired results.