Over the last few years, the rise of Creatine (Cr) as a nutritional supplement has attracted much interest from both the media, athletes and coaches. For intense exercise of 1 - 10 seconds, energy comes from phosphocreatine (Pcr) stored in the muscles. However Pcr is only available in limited supplies and is rapidly depleted and requires 2-5 minutes to replenish the stores. As football requires short bursts of intense activity interspersed with walking and jogging, Pcr is burnt during sprints and then restored during these lower intensity activities.

Cr is found naturally in meat and fish although not in the concentrations required by athletes. For example, 1 kg of fresh uncooked steak contains 5 g of Cr and eating this much meat is neither advisable nor practical. The body's Cr content can be increased through Cr supplementation in the form of tablets. According to researchers, 20g a day of creatine monohydrate during 7 days may increase body Cr by up to 50% although this varies between individuals. Some athletes combine Cr with carbohydrate supplementation to increase body Cr concentration. However, an increase in body mass due to water retention after Cr supplementation may also occur which can be disadvantageous in soccer. Caffeine intake has also been shown to eliminate the beneficial effects of Cr.

A growing number of studies show that Cr supplementation improves recovery between high intensity bouts, increases power and muscle strength during short high intensity work, allows for higher sustained power output, reduces blood lactate levels and may improve sprint times. This shows that Cr maybe useful in team sports such as soccer and rugby. Much laboratory data is however, inconsistent and further research is needed to look at the long-term effects of Cr on the health and performances of athletes. This is particular important as serious kidney problems have previously been reported.

The B-complex vitamins serve an important function in the energy yielding breakdown of fat, carbohydrate and protein. However, detailed research has shown that vitamin supplementation does not improve exercise performance. If a particular vitamin deficiency is found in an athlete, then supplementation will help. However, most sports nutritionists state that athletes who have a well-balanced diet will not need additional vitamins. Those who take vitamin supplements should be aware that an excess in some vitamins may lead to various side-effects. For example, excess Vitamin C may lead to the formation of kidney stones and vitamin B6 can induce liver and nerve damage. Pangamic acid or as it is commonly known "vitamin B15", is often consumed by athletes. They believe it improves oxygen uptake in the blood and reduces blood lactate build-up, thus reducing fatigue. However, research shows no physiological benefits and as Pangamic acid apparently serves no particular purpose in the body, its usage seems worthless. Plus, concern remains that this substance may be harmful.

Similarly, mineral supplementation seemingly does not provide any benefits to athletic performance. Indeed, excess consumption of minerals can lead to many uncomfortable or dangerous side-effects. One of the few problematical minerals in athletic performance is iron. This particular mineral plays an important role in exercise as it is required for the formation of haemoglobin and myoglobin, which bind oxygen in the body, and for enzymes involved in energy production. Low iron stores are often observed in female athletes and long distance "endurance" athletes. Iron supplementation does not improve performance unless taken by iron deficient athletes. Thus, apart from those who have a clinical need for iron, no athlete should take supplements due to the potential health risks.

The trace mineral Chromium is an essential micronutrient and is often taken as a supplement by athletes. Chromium plays a role in insulin production this facilitating protein synthesis, increasing fatty acid metabolism and promotes the transport of carbohydrate. Strenuous exercise actually increases the loss of chromium and this may lead to a deficiency. Due to it's role in protein synthesis (anabolic nature), athletes believe that chromium alters body mass and composition and will help build muscles. Scientific evidence proves the contrary in that chromium supplements provide no ergogenic benefits. Furthermore, excess chromium can lead to headaches and mood disorders as well being toxic for the kidneys. Experts advise that only when a deficiency is reported should moderate doses of chromium be taken.

Coenzyme-Q is a vital component in energy production. It is found naturally in small amounts in meat and seafood. Variable results have been obtained from scientific studies on exercise performance. For example, aerobic power and exercise performance was improved after ingestion. However, other studies showed no improvements. Coenzyme-Q has been shown to be beneficial in treating patients with congenital heart failure and other cardiovascular problems. More data is needed on the effects of this substance.

Athletes should be aware that increasing protein intake beyond recommended levels is unlikely to result in additional increases in muscle tissue synthesis because there is a limit to the rate at which protein tissue can be accrued. Extra protein above what the body requires may end up as body fat. It is worth noting that the customary diets of most athletes generally provide sufficient protein to cover even the increased amounts that may be needed during intense training.

The use of individual amino acids to enhance performance has also been studied. One proposal is that administration of branched-chain amino acids (BCAAs) may enhance endurance performance by delaying the onset of central nervous system fatigue. It has also been proposed that BCAAs may extend performance by serving as substrates for energy expenditure. Glutamine is a non-essential amino acid which helps augment protein synthesis and prevents breakdown (muscle wasting). It also seems to play a role in promoting muscle glycogen replenishment after exercise.

Finally, Beta-hydroxy-beta-methylbuyrate (HMB) helps prevent or slow muscle damage associated with intense physical effort. It may also increase muscular strength but it's exact mechanisms are not known. HMB seemingly inhibits protein breakdown through retaining nitrogen. More research is needed to study the positive and negative effects on both exercise and health from taking these substances.

Bicarbonate loading has been shown to give athletes a distinct advantage in short high-intensity exercise (lasting between 30 and 120 seconds) such as the 400m by neutralising or buffering the accumulated lactic acid which is linked to fatigue. For exercise lasting longer than 7 minutes and which is less intense, smaller amounts of lactate acid are produced thus decreasing the need for neutralisation. Although soccer involves periodic high-intensity exercise resulting in high lactate levels, the prolonged nature of the game rules out the use of alkalinizers. Furthermore, various unpleasant side-effects such as gastrointestinal discomfort (vomiting, stomach ache and diarrhoea) may occur from ingestion.

Overall, we can conclude that on the whole nutritional supplements are generally ineffective in improving athletic performance with the major exception being Creatine. They may also lead to unpleasant or perhaps dangerous side-effects and are often expensive. Supplementation seems only beneficial when a reported dietary deficiency is reported, such as low iron count in the body. Nutrition advice should be provided only after the athlete’s health, diet, supplement, drug use and energy requirements have been carefully reviewed by a qualified nutrition expert or doctor. Furthermore, anyone interested in trying out supplements, again should consult a qualified expert in health and nutrition.