By Leslie Bonci
Leslie Bonci, MPH, RD, is Director of the Sports Medicine Nutrition Program at the University of Pittsburgh Medical Center Health System, and a consultant to the University of Pittsburgh Department of Athletics, the Pittsburgh Steelers, Pittsburgh Ballet Theater, and several Pittsburgh-area high schools.
Training & Conditioning, 10.9, December 2000, http://www.momentummedia.com/articles/tc/tc1009/choices.htm
It’s astounding how many products there are on the market that fall under the umbrella of supplements. From performance enhancers to memory boosters, the range and sheer number continue to sprawl at a seemingly exponential rate. Typical outlets such as grocery stores, health clubs, and drug and natural food stores have been dwarfed by Internet companies and infomercials. The end result is 24/7 availability of whatever it is one chooses to take.
The ever-increasing availability of products raises concerns about purity, quality control, and safety. It is imperative that athletic trainers and conditioning experts present non-biased, science-based information to athletes with a rationale for use, or avoidance. Remember, everyone is going to have a different response to a product, and what works for you may not be best for the athletes you train. Each athlete’s well-being is the bottom line, and recommending any product, however innocuous it may sound, that has an ergolytic effect, or causes an athlete to test positive for a substance banned by his or her athletics governing body, is obviously not acting in an athlete’s best interest.
This article examines some of the up-and-coming supplements, focusing on their claims, research, effects on performance—positive and detrimental—and dosing. You may be familiar with many of these; others may sound foreign. But be assured, student-athletes will be asking you about them before long.
CONJUGATED LINOLEIC ACID (CLA)
Conjugated linoleic acid is a fatty acid found in meat and dairy products. It may play a role in weight management by preventing fat cells from increasing in size. A recently completed human study found that CLA supplementation made it easier for people to stay on a diet, and resulted in decreased body fat, increased muscle mass, and improvements in insulin levels. Interestingly, when weight was regained, the CLA-supplemented group only gained 50 percent of the weight as fat, in contrast to the non-supplemented group, where fat comprised 75 percent of the regained weight.
CLA supplements are produced from sunflower oil. The recommended dosage is one to four grams of CLA/day. There are no long-term studies on its safety. This may be an appropriate adjunct to weight loss for those who have had difficulty sticking to a diet, but it is not the magic bullet—good eating habits and exercise are still essential for successful weight loss.
NORANDROSTENEDIONE and NORANDROSTENEDIOL
Norandro products are hormone precursors to testosterone, with fewer androgenic effects (acne, balding, prostate growth, and general masculinizing effects), and more anabolic results (increased protein synthesis and muscle mass). They are converted in the body to nandrolone, which is a derivative of testosterone and is used clinically to treat diseases that cause muscle wasting. Nandrolone is capable of producing significant increases in lean muscle mass, which is augmented by strength training. This product can also increase fat loss.
So what are the drawbacks? There is no evidence to suggest this product is safe. The FDA does not regulate the purity of norandro, and of greatest importance, this product is banned in the NCAA, IOC, and the NFL. A small dose of 50 to 100 milligrams can result in a positive drug test for nandrolone up to seven days after ingestion.
Carnitine is a nitrogen-containing carboxylic acid synthesized from the amino acids lysine and methionine. It is also found in red meat and dairy products. Carnitine is involved in fat metabolism by serving as an essential cofactor in the oxidation of long-chain fatty acids by the mitochondria. Carnitine also affects the metabolism of acetyl coenyzme A, which plays a key role in ATP production. Carnitine may help free coenzyme A molecules, acting as a reservoir and allowing acetyl coenzyme A to enter the Krebs cycle at a later time. This, in effect, would supply another source of ATP production during exercise. It would also decrease lactic acid production and improve exercise performance.
Another theory that ties carnitine supplementation to aerobic exercise suggests that this supplement may increase fatty acid oxidation, therefore sparing glycogen and glucose and delaying fatigue during endurance exercise. Tied into this, supplement manufacturers claim that carnitine leads to significant losses of body fat.
While carnitine deficiency is associated with muscle weakness, fatty acid accumulation, and cardiomyopathy, studies have not shown any effect of short-term supplementation on fuel metabolism during exercise or any improvement in performance.
Note that the form of carnitine is important. L-carnitine, propinyl L-carnitine, and L-acetylcarnitine were used in the studies. The safety, bioavailability, and efficacy of other forms is unknown, and the D, or D,L forms can impair exercise performance by causing significant muscle weakness. Dosages used in the studies ranged from 0.5 to six grams/day, with larger dosages resulting in nausea and diarrhea.
Ginseng is a group of plants in the species Panax. There are three primary species of ginseng: Asian ginseng (Panax ginseng and Panax japonicus) and American ginseng (Panaz quinquefolius L). Siberian or Russian ginseng (Eleuthrococcus senticosus) is not a true ginseng, but it is often found on the shelves next to all the other products. The amount of ginsenosides, the active ingredient in ginseng, can vary tremendously among products. The species, soil, age of roots, part of the plant being used, and extraction methods can alter the potency of the product.
Claims range from enhanced exercise endurance, increased energy, and mood improvement, to a boost in the immune system. There has not been enough research that has demonstrated a consistent positive effect on exercise performance. Purity is a concern, as well as the amount used. Dosages in excess of three grams/day can cause insomnia, nervousness, and irritability. Ginseng may affect blood glucose and should not be used by diabetics, individuals on blood-thinning medications, or those on antidepressants. Siberian ginseng root is contraindicated in hypertensives.
Phosphatidylserine (PS) is a naturally occuring phospholipid found in the brain cortex. It may be involved in blunting levels of corticotrophin (ACTH) and exercise-induced cortisol production. Increased cortisol levels can have a catabolic effect on skeletal muscle. Supplement manufacturers suggest that phosphatidylserine can prevent muscle catabolism.
The normal body response to exercise is to increase cortisol levels. Cortisol production suppresses proteins that increase the inflammatory process. The research on PS is fairly limited, but if the effect of PS supplementation is to blunt the cortisol response, the result could be a delay in repair of damaged tissue and/or recovery from exercise. Therefore, the effects on cortisol production may be more performance detracting than enhancing.
PS is sold as tablets, capsules, powder, and chewing gum, with a recommended dosage of 100 to 800 milligrams/day.
Soy is a hot topic from a health standpoint. Although soy is consumed in other countries as a food, in the U.S. it is used more often as a supplement, and is added to sports bars, protein powders, and cereals. Soy protein may have cholesterol-lowering benefits, and the isoflavones or phytochemicals in the soy may help to preserve bone density and may exert a cancer risk-reducing effect.
It is precisely this component of soy, the isoflavones, that may be harmful if consumed in large quantities. Isoflavones are weak estrogens, and consuming large amounts may increase breast cell proliferation.
To be on the safe side, it is better to eat soy foods (tofu, soybeans, soy milk, soynuts) and steer clear of soy pills and powders. Soy is an excellent protein for the body, but too much may do more harm than good. The heart-healthy dosage of soy protein is 25 grams/day, and the upper limit for isoflavones is 100 milligrams/day.
It is important to read product labels for the isoflavone content.
Whey is a natural byproduct in cheese production. It is an ingredient in many protein powders, along with creatine, glutamine, and branch-chain amino acids, and is touted as being capable of boosting the immune system as well as exerting an anabolic effect. Some manufacturers recommend 100 to 125 grams of whey protein/day, which may be too much, especially in conjunction with other protein foods. The simple formula for the maximum usable amount of protein is: body weight in pounds = number of grams of protein/day.
There is no evidence that whey protein increases muscle mass or glutathione levels, which is a marker of the immune response. In addition, the technique used to process the whey can render it unavailable for use. Whey that is heat- or mechanically processed is not as bioavailable. Whey is considered safe, but fairly costly, and one’s needs can be more easily met by consuming milk.
Yohimbine is derived from the bark of the yohimbe tree. It stimulates the release of the hormone norepinephrine. Claims include an increase in sex drive, weight loss, and increased muscle mass.
The recommended dosage is 10 to 20 milligrams/day divided into four doses. As little as four milligrams can cause nervousness, insomnia, anxiety, increased urinary frequency, dizziness, tremors, headaches, swings in blood pressure, nausea, vomiting, and tachycardia. Yohimbe use is particularly contraindicated in those with high or low blood pressure, liver or kidney disease, or anyone on tricyclic antidepressants. It is interesting to note that this product is not approved for use in Germany due to concerns about its safety.
VITAMINS C and E
Vitamin supplementation continues to be very popular, and the National Academy of Sciences has recently released new recommendations for Vitamins C and E. Both of these vitamins function as antioxidants and, theoretically, should help to minimize the oxidative damage associated with exercise. But, there is little evidence to show that Vitamin C supplementation affects oxidative status, although it may help to boost the immune system and decrease cataract risk. Vitamin E may be of benefit to athletes exercising at high altitudes.
The new Daily Recommended Intake (DRI) for Vitamin C is 75 milligrams for women and 90 milligrams for men, and the Tolerable Upper Intake is 2000 milligrams. Diarrhea and nausea can occur with dosages greater than 1000 milligrams/day, and large doses can interfere with anticoagulant medications and should not be used in anyone with hemochromatosis.
The DRI for Vitamin E is 15 milligrams, with 1000 milligrams as the Tolerable Upper Intake. Natural Vitamin E (d-alpha tocopherol or RRR-alpha tocopherol) is better absorbed than other forms.
The list of products athletes reach for to increase performance, lose weight, and decrease fatigue—among a hundred other reasons—is continually expanding. But so is the body of research and our knowledge about them. And while it’s hard to stay on top of all the newest products, one cannot discount the importance of education in enabling athletes to make wise decisions about products they choose to put into their bodies.
Here are some guidelines to help you address the supplement issue:
• Beware the “potato chip” approach to supplementation—“no one can stop at just one”—and the “more is better” philosophy.
• It is important to stress to student-athletes that supplements that are natural are not necessarily safe and are not efficient fuel sources for an athlete.
• Ask what your athletes take, look at the labels from the products, and take a few minutes to evaluate these items.
• Reinforce that proper fuel, training, and rest provide far more benefit than any supplement ever will. Supplements are the icing, but let them eat cake!
For further information, go to our Web site, at www.athleticsearch.com and type “supplements” into the search field.