Herbal Supplements: College Station ISD

Labels on dietary supplements can be misleading. Containers may include substantially more, but usually less, of the listed amounts of ingredients, and substances may be added?some of which can cause failed doping tests for athletes?that are not listed on the label.

Many of the early studies claiming a positive effect of Chinese ginseng on exercise performance were of poor quality. Better research has failed to show any benefits of either Chinese or Siberian ginseng on athletic performance.

Popular herbs consumed as "muscle building" anabolic agents include yohimbine, smilax, tribulus, wild yams, and gamma oryzanol. The plant steroids found in many of these herbs cannot be converted by the human body into testosterone or other anabolic steroids. Claims that these agents can increase muscle mass have little or no scientific basis.

The herb Ephedra Sinica contains ephedrine, a stimulant to the nervous system and cardiovascular system, is used to accelerate fat loss and enhance feelings of "energy." There is no solid evidence that herbal ephedra can improve athletic performance, but the use of ephedrine-containing products can result in serious side effects, including death.

Herbal dietary supplements are touted as "natural, safe, and effective" products that can decrease body fat, elevate blood levels of testosterone, increase muscle mass, enhance energy, improve strength and stamina, and generally improve health and athletic performance. However, these supplements and the advertising that promotes their use are essentially unregulated. Athletes and non-athletes alike must be alert to the potential risks of using herbal supplements and be realistic about the likelihood that they will enhance exercise performance.

In this roundtable, four experts in sports nutrition have addressed some of the important issues related to the use of herbal supplements. Ellen Coleman, Ron Maughan, Suzanne Nelson-Steen, and Rob Skinner have all worked closely with elite and non-elite athletes, helping them with a wide variety of nutritional problems. Moreover, they have conducted extensive research and have published many books and articles on sports nutrition.

COLEMAN: Not necessarily. For example, Gurley and colleagues (2000) analyzed the amount of ephedra in 20 herbal dietary supplements and found large discrepancies in the contents. Half the products varied by more than 20% from the amount listed on the label, and one product contained none of the active ingredient. Five products contained substantial quantities of nor-pseudoephedrine, a drug listed as a Schedule IV controlled substance by the U.S. Drug Enforcement Agency (DEA). The researchers also found extensive lot-to-lot variation from the same manufacturers, indicating poor quality control. They also reported that label claims for ephedra were not indicative of the quantity present, which ranged from 0 to over 150 percent of the amount listed on the label.

Consumer Lab is a company that provides independent test results and information to help consumers and healthcare professionals evaluate and select dietary supplements. They found that only 14 out of 25 echinacea products passed review, nine of 17 valerian products, and 19 of 27 saw-palmetto products.

As another example of how athletes cannot trust the labels on dietary supplements, the Medical Commission of the International Olympic Committee in 2002 found that of 634 non-hormonal nutritional supplements tested from 13 different countries, 94 (14.8%) contained substances that were not listed on any label and that could have led to a positive doping test. Out of these 94 samples, 23 contained compounds that could be metabolized to either nandrolone or testosterone, 64 contained substances that could have been metabolized to testosterone, and seven contained precursors of nandrolone alone.

In another report, Green and associates (2001) bought 12 brands of over-the-counter steroid prohormones from stores that cater to athletes. Eleven out of 12 brands did not meet the minimal labeling requirements established by the 1994 Dietary Supplement and Health Education Act (DSHEA). One brand contained 10 mg of testosterone (a controlled steroid); another contained 77% more prohormone than the label stated, and 11 of 12 contained less than the label stated.

MAUGHAN: Most people buying supplements trust the information on the label to be correct and have no way of checking this. However, as Ellen Coleman has described in some detail, several laboratories have found that certain supplements contain little or none of the expensive ingredients listed on the label and/or contain substances not listed on the label. In some cases, supplements have been found to contain small amounts of substances that can cause a positive drug test (nandrolone, testosterone, caffeine, ephedrine, and others). Even if you can find a laboratory to do the necessary analysis, there is no easy way to get your money back.

NELSON-STEEN: While prescription and over-the-counter drugs and food additives must meet the Food and Drug Administration?s safety and effectiveness requirements, dietary supplements bypass these regulations. These products can go to market with no testing for efficacy, safety, or potency, and there is no guarantee that the product is what it says it is on the label since there is no legal standard for processing, harvesting, or packaging.

Some studies with Chinese ginseng (Panax ginseng) claim a wide array of beneficial effects on exercise-related performance. What is your opinion of the relative quality of the published research on Chinese ginseng, and how likely do you think it is that an athlete would experience improved sport performance when using this herb?

MAUGHAN: There are some studies that show beneficial effects of Chinese ginseng on a range of performance tests, but there are even more reports that show no effects on performance. It is important to recognize the differences in the quality of the evidence. Many of the studies showing positive effects were not well designed. Often there was no placebo group, and subjects were aware that they were being given something that might improve their performance. The subject numbers in these studies were often small, so the results may have been just due to chance. It is much harder in the world of science to get a negative finding published, so most studies that find no benefit are never made public. There is another problem in that the purity of the products used was usually not checked, and benefits claimed on mental concentration, reaction time, strength, power, endurance, and other tests may well have been due to the presence of caffeine or other added stimulants in commercial preparations, rather than to ginseng itself.

COLEMAN: Ginseng plants contain varying levels of several different chemicals that appear to exert opposing pharmacological effects. This natural variation could conceivably explain the wide array of proposed beneficial effects on exercise performance, but it is more likely that a lack of standardization of ginseng?s biologically active compounds, variability in dosage and administration, and differences in the type of ginseng used influenced the research results. In my opinion, it is unlikely that ginseng will improve athletic performance in a research study that controls for the placebo effect.

NELSON-STEEN: The highly advertised use of Panax ginseng to enhance physical performance in healthy individuals has not been substantiated in recent clinical trials. I doubt that ginseng has any reliable effect on performance.

SKINNER: The earlier published studies on Panax ginseng would not stand up to today?s scientific standards. The likelihood of an athlete receiving performance-enhancing benefits from Panax ginseng is small, but you can never discount the placebo effect.

SKINNER: The biggest differences between these herbs are the geographic locations in which the plants grow, the active ingredients, and the parts of the plants used for supplements. Chinese ginseng is native to Korea and China, whereas "Siberian ginseng" includes about 20 species of similar shrubs found in China, Russia, Korea, and Japan. Siberian ginseng extract was developed in the former Soviet Union as a substitute for Chinese ginseng, with claims of even greater health benefits. Unfortunately, there is little solid evidence that these products have any real health or performance benefits.

COLEMAN: Siberian ginseng is not a true ginseng. It belongs to the same family but not the same genus as Chinese ginseng. Although both herbs have some similar properties, as Rob Skinner has indicated, there is essentially no research support for a positive effect of Siberian ginseng on exercise performance.

MAUGHAN: To expand on what Rob and Ellen have said, it has been claimed that Siberian ginseng can improve endurance performance by increasing the use of fat as a fuel, thus sparing the body?s limited carbohydrate stores. A recent investigation tested this hypothesis in a randomized, double-blind study using a crossover design. There were no effects on fat and carbohydrate oxidation during 2 hours of moderate cycling exercise, and there was no effect on performance of a 10-km time trial that followed. Evidence for benefits usually comes from poorly controlled experiments.

What are the most popular "anabolic" herbal supplements? Can steroids found in plants be converted to testosterone in humans? What is the evidence that any of these "musclebuilding" herbs actually helps build muscle and increases strength? Are there any potentially harmful side effects of using these supplements?

COLEMAN: Popular purported anabolic herbs include yohimbine, smilax, tribulus, and gamma oryzanol. Yohimbine (extracted from yohimbe bark or from a South American herb, Quebracho) supposedly increases serum testosterone levels (presumably by increasing blood flow through the testes), thereby increasing muscle size and strength. There is no research basis for these claims. Because yohimbine can increase blood pressure, people who have diabetes or cardiovascular, liver or kidney disease should not take yohimbine. Moreover, red wine, liver, and cheese should be rigorously avoided when yohimbine is used to prevent a sudden and dangerous increase in blood pressure. (These foods contain the amino acid tyramine, which can cause blood vessel constriction and raise blood pressure. The liver normally inactivates tyramine, but yohimbine interferes with the inactivation process.)

COLEMAN: Smilax (a genus of desert plants containing several species of sarsaparilla) allegedly increases serum testosterone levels and serves as legal alternative to anabolic steroids. Smilax does contain saponins (sarsapogenin and smilagenin) that serve as the building blocks for the laboratory production of certain steroids, but this conversion does not occur in the human body. There is no evidence that smilax is anabolic or functions as a "legal replacement" for anabolic steroids. The saponins in smilax stimulate urination, bowel evacuation, sweating, and coughing, any of which could be harmful to sport performance.

Tribulus Terrestris (puncture vine) theoretically increases testosterone levels indirectly by increasing the release of luteinizing hormone from the pituitary, thereby resulting in greater production of testosterone by the testes. However, research on tribulus supplementation in weightlifters showed no effects on body weight, percentage fat, total muscle mass, or muscle strength. When taken in recommended doses, tribulis has not been associated with adverse side effects in humans.

Gamma-Oryzanol (a plant sterol derived from rice bran oil) purportedly raises serum levels of both testosterone and growth hormone. As with other plant-derived steroids, the best research has failed to show any anabolic effect of supplementation with oryzanol. Due to poor absorption characteristics of oryzanol (less than 5% is typically absorbed from the gastrointestinal tract), there are no apparent adverse effects.

NELSON-STEEN: Extracts of wild Mexican yams of the Dioscorea family are also popular "anabolic" supplements. These plants contain a steroidal substance called diosgenin, which can be converted by a series of chemical reactions in a test tube to dehydroepiandrosterone (DHEA), an anabolic hormone that can in turn be converted by the body to other steroids, including testosterone and estrogen. However, these reactions that convert diosgenin to DHEA in the laboratory do not occur in the human body! Products that claim that wild yams can lead to the formation of DHEA in the body or increase testosterone levels are a total scam. Because yam extracts are not converted to DHEA by the body, adverse side effects are unlikely.

MAUGHAN: We have to recognize that the anabolic androgenic steroids are powerful pharmacological agents. They are subject to tight controls by the agencies that license the use of such drugs. Any product on sale that had a significant anabolic effect would be subject to these controls, and the fact that the "anabolic" herbal supplements are not controlled is a clear indication of their lack of effect.

Mahuang or Chinese ephedra (Ephedra Sinica) contains ephedrine and related compounds that have stimulant effects similar to those of adrenaline (epinephrine). Does herbal ephedra have any effects on exercise performance? Is it harmful?

MAUGHAN: Most reviews of the available evidence have concluded that neither ephedrine nor any of the compounds related to it will improve performance at the doses normally used. There is little information about the effects of much higher doses, but the adverse health risks of high doses far outweigh the limited possibility of performance enhancement. The evidence that pseudoephedrine?found in many supplements, decongestants and cold remedies?has no beneficial effect is so compelling that there has been a proposal for it to be removed from the list of banned substances for athletes.

NELSON-STEEN: The International Olympic Committee and National Collegiate Athletic Association ban ephedrine, so athletes should not even consider using ephedra or other products that contain ephedrine. Because of its stimulating effect on the nervous system, ephedrine is found in some popular weight loss and "energy-enhancer" products. It is often combined with caffeine or ingredients such as koala nut or guarana that contain caffeine. Since they are stimulants, ephedra and caffeine may make athletes "feel" energized, but they do not provide athletes with energy. Adverse side effects of ephedrine use include increased blood pressure, heart rate irregularities, insomnia, nervousness, tremors, headaches, psychoses, seizures, heart attacks, strokes, and death. Athletes have described many negative effects of taking caffeine or ephedra, including dizziness, lack of focus, irritability, and heart palpitations, any of which could adversely affect performance.

COLEMAN: Herbs that contain ephedrine (ephedra) and caffeine (guarana) have not been shown to improve exercise performance, but military research suggests that a combination of synthetic ephedrine and caffeine (0.8 to 1.0 mg of ephedrine per kg of body weight and 4 to 5 mg of caffeine per kg consumed 11/2 hours before exercise) can improve both anaerobic and high-intensity aerobic performance. In addition to the adverse effects outlined by Dr. Nelson-Steen, ephedrine also raises body temperature and increases the risk of developing a heat injury during exercise in warm weather.

SKINNER: Most proponents of ephedra use stick to their guns and claim that adverse reactions only occur in people who have pre-existing medical conditions or who take more than the recommended amounts. The most interesting information to me is the accounts of autopsies conducted on individuals who have died, with ephedra use being a suspected cause of death. For example, in one case of the sudden death of a 32-year-old female with no cardiovascular of lung problems, ephedra was the only drug detected in her system.

COLEMAN: Many athletes often incorrectly assume that herbal products are safe and without the side effects of medications because the products are marketed as "natural" and can be purchased without a prescription. This misconception is potentially dangerous because herbs, like medications, can have adverse effects. The risk of side effects is further increased when certain herbs are combined with prescription drugs or over-the-counter medications.

Health care providers should encourage individuals to report what herbs they take. As many as seven out of ten herbal medicine users never tell their physicians about the herbal products they are taking. The ability of physicians to correctly diagnose and treat an illness or disease is limited when they are unaware of a patient?s use of herbs. In addition, people should be educated regarding the proper use of herbs and when to report a problem to their physicians.

NELSON-STEEN: I?m concerned about the number of products being marketed as energy drinks that contain various herbs, caffeine, and ephedra. Not only can their consumption potentially cause a positive drug test in a collegiate or internationally competitive athlete, but there is also a risk for negative side effects and interactions among the compounds.

MAUGHAN: I do believe that many of the traditional herbal remedies probably have some mild benefits for health and performance, but these effects are trivial in comparison with those achieved with modern drugs. Although I remain skeptical, there does seem to be some evidence that echinacea can stimulate the immune system and help in the treatment?but not the prevention ?of colds, flu, and upper respiratory tract infections.

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Eschbach, L.C., M.J. Webster, J.C. Boyd, P.D. McArthur, and T.K. Evetovich (2000). The effect of Siberian ginseng (Eleutherococcus Senticosus) on substrate utilization and performance during prolonged cycling. Int. J. Sports Nutr. Exerc. Metab. 10:444-451.