Competitive cyclists who have achieved maximal results from their training programs often turn to extrinsic aids (termed ergogenic aids) to enhance their performance.  These include mechanical aids (equipment), psychological aids (hypnosis, psychotherapy), pharmacological aids (erythropoietin) and nutritional aids (creatine phosphate, vitamins, minerals).

The use of performance enhancing dietary supplements can be traced back to the Romans who reportedly drank lion's blood to improve their strength and courage. Today, unfortunately, nutritional supplements are frequently promoted with unsubstantiated claims so beware of the claims and of the Placebo Effect that you can create.

(The placebo affect results from our optimism and hope that a medication, supplement, or training program will be beneficial, biasing us toward a positive impression of the results.)

There are few shortcuts for a well-designed training program supported with sound nutrition. And although there may be little risk in trying supplements in addition, there is a monetary cost for those on a limited budget, as well as the potential to lose focus on the real need for a good training program.

Following are a compilation of the main dietary supplements that have been advocated as ergogenic aids over the last few years.

AMINO ACIDS

Purified amino acids (particularly arginine, ornitine, lysine, and tyrosine) have become a popular, if expensive, form of protein supplementation. Five well-performed studies have failed to demonstrate that either singly, or in combination; there is any significant effect on human growth hormone secretion or direct measures of muscular development, strength, or power.

Amino acids are the building blocks of proteins and are present in almost all the foods we eat. As with vitamins, a balanced diet, which replaces Caloric expenditures, should provide more than enough of the essential amino acids. Amino acids sold in the health food stores have no added advantage over a peanut butter sandwich and a glass of milk, and don't have nearly the taste appeal.

Protein should provide approximately 20% of our daily Caloric intake. It normally provides less than 5% of the energy expended during exercise and is used as a source of energy for normal cell functions only during starvation or extreme malnutrition. Studies in athletes have shown that 1.2 grams of protein per kilogram per day is adequate for muscle development in most sports, and protein in excess of 2 grams per kilogram per day will be turned into fat. Most cyclists get more than enough protein for cell building and repair from the foods they eat, and any excess - whether from supplements or in the diet - will be either converted to body fat or burned inefficiently as fuel.

In addition, excess protein:

has a diuretic effect increasing the risk of dehydration
can cause diarrhoea and abdominal bloating
may lead to chronic renal damage
can lead to gout
may increase total body calcium loss

ANTI-INFLAMMATORIES

Common wisdom holds that taking anti-inflammatory or aspirin before cycling or other vigorous activity can reduce muscle soreness. However one study concluded that even at large doses (20 mg per kg or 4 standard aspirin for the average rider), aspirin did not delay the onset of muscle pain during exercise or reduce the perceived intensity when it occurred. In addition there is good evidence that using agents such as motrin (ibuprofen) or aspirin on a regular basis increases the incidence of ulcers and can cause kidney and liver damage. How much is too much? If it's a regular part of your program, it's probably too much, and may be a sign that you are riding or training too hard.

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ANTIOXIDANTS

There is evidence supporting the long-term benefits of antioxidants. However, short term studies are more controversial. But at least one has suggested that the use of antioxidants in the form of vitamins C, E, and beta carotene decreased muscle damage in a group of runners as compared to a control group, and there are numerous anecdotal reports that vitamin C taken before a ride diminished the amount of muscle soreness the next day. However, none have suggested a positive effect of any of the antioxidant vitamins on actual exercise performance although one study from the University of Birmingham did suggest that a group of riders that took 500 mg of Vit C and exercised strenuously for 60 minutes, recovered 85% of their muscle strength at 24 hours vs 75% in the placebo group.

The bottom line is that very little evidence to support the short-term benefit of antioxidants for the competitive athlete - and plenty of controversy remains as to the long-term health benefits. But there is no evidence that they will do you any harm.

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ATP (oral)

ATP is the chemical compound that provides the energy for muscle action. It is composed of a base (adenosine), a sugar (ribose) and three phosphate groups. It is the high energy phosphate bonds that contains the chemical energy which is stored in this molecule, and it is the breaking of these bonds during cellular metabolism that power muscle contractions and other vital cellular functions.

An oral supplement of this compound is available. The only controlled study available demonstrated a 7 % increase in mean power as demonstrated by a Wingate performance test (a 30 second interval of maximal performance, i.e. anaerobic, on a bicycle ergo meter) after taking a 14-day supplement of 0.2 grams per kg body weight per day of ATP-E. How this translates to improvement in actual cycling performance or a positive impact on an end of race sprint is yet to be determined. Until further studies confirm this preliminary impression, and translate any benefits into actual improved cycling performance, this supplement should be considered as unproven.

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ELECTROLYTES

The minerals sodium, potassium, and chlorine are collectively referred to as electrolytes. They are dissolved in the intra (within) and extra (outside) cellular water as charged particles (ions) and are responsible for maintaining a proper electrical gradient across the cellular membrane - required for the proper functioning of each cell.

A normal diet contains these three minerals in excess, and the kidneys control the loss from the body. As a result there is no requirement for diet supplementation except in extreme conditions.

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FAT(DIETARY)
Over the last few years it has been suggested that a diet composed of at least 30% fat Calories improves competitive aerobic performance over a high carbohydrate diet - relatively restricted in fat Calories (20-25%).

There are a number of physiologic studies that demonstrate fat CANNOT sustain high level (high VO2 max.) aerobic and anaerobic activity (the cause of the "bonk" as glycogen stores are depleted). And others that have shown that a high carbohydrate diet is best for maintaining glycogen stores while a chronic deficit in replacing carbohydrates has been proven to lead to chronic fatigue. In addition it has been proven beyond any doubt that a long-term high fat diet leads to heart disease. And for those who still aren't convinced, it should be remembered that even the leanest athlete has plenty of stored fat available without any need for diet supplements.

A variation on this theme is reflected in the energy bars that contain fat and are alleged to improve performance, SELECTIVELY increase fat metabolism, and aid in weight loss. While there has been some evidence that an occasional long slow recovery ride in your training program MIGHT improve the ability to metabolise or use stored fat Calories for muscle energy, there is no scientific basis for the claims made by these products that eating any particular food or food type (i.e. fat) will enhance fat metabolism.

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FIBRE
Fibre is a general term for non-digestible carbohydrate in the diet and refers mainly to the cellulose, lignin, and pectin found in fruits, grains, and vegetables. Currently there is no recommended minimum for dietary fibre and no special requirements for cyclists or other athletes. On the other hand, there is good evidence that too much fibre may bind minerals such as zinc in the intestinal tract, resulting in poor absorption. A high fibre diet also may lead to abdominal bloating and cramping. The most reasonable approach seems to be a well balanced diet with enough fruits, grains, and vegetables to maintain regular bowel function.

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GINSENGS

Ginsengs are herbal preparations extracted from the roots of plants in the family Araliaceae, and contain a wide variety of chemical substances. Thus all ginsengs are not equivalent as far as ergogenic potential. Some may work at the higher centres of the central nervous system to enhance both mental and physical stamina.

A commonly advertised commercial product, Ginsana, claims to produce lower lactate levels and increase VO2 max. However, as with many of the herbal products, there are as many studies supporting the claims as refuting them - a common situation with ineffective claims. And the most recent, which are the most carefully controlled, failed to demonstrate any change in maximal aerobic performance after two and three weeks of supplementation.

At recommended doses, ginseng can produce the "ginseng abuse syndrome" - high blood pressure, nervousness, and confusion. Although this compound may be considered as "possibly" effective, needing further study, try it at your own risk!

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MINERALS  

Minerals are chemical elements found in the body either in their elemental form or complexed with organic compounds. Like vitamins, they are essential for normal cell functioning. The two most prevalent minerals, calcium and phosphorus, are major components of bone while sodium and potassium are found in all tissue fluids, both within and around cells. Magnesium, chloride, sulphur, and zinc are other minerals that play a key role in cell function. The trace elements iron, manganese, copper, and iodine are found in much smaller quantities, but play essential roles as catalysts in basic cellular chemical processes.

These minerals, found in all foods, are kept in balance through internal regulation of absorption and excretion. As a result, adequate tissue levels are easily provided by a balanced diet. Multiple studies of body tissue mineral status in athletes failed to identify any deficiencies in those ON A BALANCED DIET compared to people engaged in normal daily activities. Athletes who are restricting energy intake to achieve a lower body weight (endurance runners for example) are the exception, and may need supplements.

It has been alleged that athletes need higher than normal levels of minerals to maintain maximum performance. However numerous studies of mineral and micronutrient diet supplementation (with the exception of iron in athletes who were clearly anaemic with iron deficiency) have failed to demonstrate an improvement in performance whenever studied.

Only calcium (for long term bone strength) and iron (in clearly deficient individuals) may be required by some athletes in increased amounts. Because of toxic side effects when taken in large amounts, minerals as a group are not recommended as routine supplements for athletes on a balanced diet that meet their Caloric needs.

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OMEGA-3 FATTY ACIDS

These "eicosanoids" are speculated to stimulate human growth hormone release, and are marketed in several energy bars containing a blend of fish and vegetable oils with omega3 fatty acids. There is currently no support for an anabolic or performance enhancing effect. Excesses may interfere with blood clotting.

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VITAMINS

Vitamins are held up as a safe and effective way of improving performance. Although coaches and trainers often recommend them, multiple studies of body tissue vitamin status in athletes failed to identify any specific deficiencies in those ON A BALANCED DIET (replacing Calories expended) compared to people engaged in normal daily activities.

It has been alleged that athletes need higher than normal levels of vitamins to maintain maximum performance. Although supplementation will improve corresponding blood levels of these vitamins, there is NO evidence of improved performance.

There is evidence that mega-vitamin programs can be harmful. The fat-soluble vitamins (A, D, E, and K) are not eliminated in the urine and can accumulate in body fat to reach toxic levels. And there have been reports that even the water soluble ones (B complex, and C which are excreted in the urine if excess amounts are taken) can be harmful at doses of 10 to 100 times the recommended daily requirements (RDA).

Vitamins act as catalysts for the metabolic (biologic) pathways that convert fats, carbohydrates, and proteins into Calories or energy. As such, they facilitate the reaction, but are not "used up" or consumed by it. This is why there is a single RDA that is independent of body size, sex, or daily energy expenditures.

If there is a concern about how your diet being well balanced, there is no harm (other than to your wallet) in using a simple over the counter multiple vitamin once a day. But vitamins are not the easy answer to increased performance.

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