Supplementation is a fast growing industry, especially in sports competition and exercise. There is an ever increasing range of vitamins and minerals that can be bought at your local supermarket and protein powders are a gigantic market, especially since the commercialisation of gyms. Creatine products are also increasing on the market, with proposed benefits to training and sprint performance. It is important for athletes to know whether any of these supplements will benefit performance, how they will affect their health, the possible side effects and whether the athlete should take them.

In sport and exercise settings, the use of dietary supplements and ergogenic aids is common among athletes seeking to enhance performance, support recovery and prevent nutritional deficiencies. When used appropriately and with professional guidance, supplements like protein, caffeine, creatine and essential micronutrients can play a role in achieving training goals. 

A food-first approach is recommended; supplements should complement, not replace, a balanced diet. All supplements should be batch-tested for safety and banned substances (e.g. Informed Sport accreditation) and athletes should consult a sports dietitian or medical professional before starting any supplementation protocol. Unregulated supplements may contain contaminants or banned substances and an over-reliance can lead to poor dietary habits or nutrient imbalances.

Protein is a chain of amino acids and provides the building blocks for all the cells in the body. It is particularly important for muscular growth and repair, and can be used as a fuel source. It is recommended that people eat 0.8g of protein per Kg of body weight. This is enough to maintain current body mass and is sufficient in providing for any possible energy needs. However, when resistance training is undertaken for muscular hypertrophy protein consumption should increase to 1.2-1.8g per Kg of body weight, in order to grow muscle size. It should be noted though, that this upper limit for an athlete weighing 100Kg is still only 180g, which would easily be consumed in a normal western diet, because meat, dairy and eggs are high in amino acids.

Supplementation is not required for most western athletes. If the athlete is a vegetarian or vegan amino acids are usually consumed through beans, nuts and legumes and would need to be monitored in order to ensure adequate amounts are being eaten. If not, then supplementation may be beneficial.

Supplementation may also be beneficial because it can improve the timing of protein consumption. Protein consumed within 1hr of resistance training may help recovery and increase hypertrophy. Excessive consumption can have a detrimental affect on health, particularly kidney function.

Protein supplements promote muscle repair, growth (hypertrophy) and recovery, particularly following resistance training or prolonged endurance exercise. Forms of protein supplements include whey, casein, soy and plant-based blends (pea, rice, etc.). Consuming 20–30g of high-quality protein post-exercise stimulates muscle protein synthesis. This is beneficial for athletes with high training loads, vegetarians/vegans or those with limited appetite post-training. Whole food protein sources (e.g. eggs, meat, dairy, legumes) are preferred, but supplements offer convenience and quick absorption.

Supplementation of these micronutrients is only needed when adequate amounts are not gained through a regular diet. Athletes with restrictive diets, high sweat rates or increased physiological demand may require supplementation, however, this should only be considered following blood tests and medical advice. Vitamins and minerals are organic compounds found in high concentrations in fruit and vegetables. Though they are all needed for proper bodily function, there are a few that are important for performance.

The important vitamins are: B vitamins, vitamin D, C, E and beta-carotene.

• B vitamins are a group of vitamins that optimise energy production as well as the building and repair of muscle tissue. B vitamins are also vital in red blood cell production.

• Vitamin D is needed for adequate calcium absorption and promotes bone health. It also helps regulate the homeostasis of the nervous system and skeletal muscle.

• The antioxidants (Vitamin C, E and beta-carotene) help protect cell membranes from oxidative damage. More antioxidants are needed because exercise increases oxygen consumption, which increases oxidative damage.

The minerals vital to performance are: Iron, Zinc, Magnesium, Potassium, Sodium, Chloride, and Calcium.

• Iron is the most important as it gives haemoglobin and myoglobin their shape allowing transportation of oxygen around the body and in the muscle. Without enough Iron, there will not be enough oxygen to maintain the higher intensities that would normally use the aerobic energy system. The lack of oxygen will also negatively affect the recovery times of the anaerobic systems and delay recovery after performance.

• Calcium is required for bone repair, growth and development, but is also a vital nutrient for muscle contraction and nerve conduction (transmission of message). Calcium and Iron are particularly important for female athletes, as they are more likely to be deficient in both.

• Zinc is required for the growth and repair of muscle tissue.

• Magnesium is required for muscular contraction and plays a role in glycolysis. A deficiency in magnesium causes an increased requirement for oxygen for submaximal output.

• Sodium, Chloride and Potassium all play an important role in neural transmission. Sodium is critical, especially as it is lost during exercise through sweat. Sports can help replace sodium and potassium.

Caffeine acts as a stimulant to enhance alertness, reaction time, concentration and reduce perceived exertion. Sources include coffee, energy drinks, caffeine gels, gum and tablets. 3–6 mg/kg of body weight taken 60 minutes before activity is shown to be effective. Caffeine is useful in both endurance (e.g. long-distance running) and intermittent high-intensity sports (e.g. football, basketball), but overuse can cause jitteriness, increased heart rate and sleep disturbance. Athletes should trial caffeine in training before using in competition.

Caffeine was removed from the WADA banned substance list as large amounts of this supplement do not provide a greater benefit than the smaller amounts that would be present in most athletes’ diets. This is because caffeine is found in coffee, chocolate, tea and many other commonly consumed products.

Previously caffeine was thought to be an ergogenic aid, which increases fat mobility converting fats to free fatty acids used for energy production. The increase in free fatty acids increases the production of ATP from fat sparing glycogen stores to be used later in the competition. However, we now know that caffeine’s main benefit is blocking adenosine in the brain. This improves the athlete’s perception of fatigue, allowing for greater performance as the athlete can go harder, for longer.

The benefits of this supplement can be felt and seen almost immediately after consumption. This is because the body does not need large amounts in order to benefit. This means that it can be consumed either before a relatively short event, throughout longer events, or even just as fatigue begins to be noticed. Regardless of when, the supplement is beneficial, especially for marathons, iron mans or multi-day cycling events.

The stimulation of caffeine also has side effects and large amounts can cause an athlete to shake or have symptoms of anxiety. These side effects would be detrimental to sports such as shooting or darts where a steady hand is vital. As a diuretic, caffeine removes water from the body. During competition, especially long competition this could become dangerous. If used, the athlete must ensure they consume greater amounts of fluids throughout the competition and afterwards in order to aid recovery.

Creatine enhances the body’s ability to rapidly produce ATP, the primary energy currency in high-intensity, short-duration activities. It may increase power output, strength and lean muscle mass and is particularly effective in sports involving repeated sprints or weightlifting. Dosage should be approximately 20g/day for 5–7 days, followed by maintenance of 3–5g/day. Creatine is well-researched and safe for most individuals, though some may experience water retention or gastrointestinal discomfort.

Creatine products are easily sourced for supplementation to help improve performance. Creatine is an organic acid and is not an essential nutrient for humans. That is, our bodies will create creatine using amino acids and other compounds. It then has a phosphorus attached to it to make phosphocreatine (PC), used to store energy in skeletal muscle.

Creatine products used for supplementation could increase PC stores and enable the alactacid energy system to be utilised for longer and recover faster. Creatine supplementation would benefit sports such as, 100m sprint, but also rugby league and soccer as recovery of this system would speed up allowing for greater repetition of sprints required in these sports.

An increase in PC would also allow for faster recovery between sets, leading to a greater overall workload. This causes greater adaptations, such as hypertrophy and increased power outputs. Studies have shown that hypertrophy increases with creatine supplementation and weight training. Creatine has also been shown to increase body mass on its own, though this is due to fluid retention needed to store the extra creatine.

It should be noted that the quality of creatine products used in supplementation varies from product to product and that practitioner only products will provide better results than over the counter supplements.Creatine does provide performance benefits, however it is easily sourced in a diet by eating meat, the body will create it as needed. Creatine products and supplementation will benefit those who need it, but it can cause short-term nausea, hypertension and cramps.