Marketed Supplements with Proven Benefits

A number of products have shown benefits in specific sports or events following well-controlled scientific trials. It is widely known that not all people will respond positively to these supplements. Indeed, some individuals may respond negatively to them. Thus, it is essential to try the supplement prior to using them in competition as well as ensuring they are used to the scientifically-proven methods (e.g. dosage, timing) suggested below.

Caffeine

Caffeine is a naturally occurring stimulant found in coffee, tea, chocolate and cola drinks that provide between 30-100 mg/serve. Some non-prescription medications such as No-Doz can provide between 100-200 mg of caffeine /tablet while a Starbucks Grande Coffee has 330 mg.

Caffeine has been well-documented by research to have the following benefits:

  • Central nervous stimulant – increases perception and reduces feeling of effort and pain
  • Improved strength and power – by stimulating the release and uptake of calcium by muscle fibres that enhances the force of muscle contraction
  • Improved repeat sprint ability
  • Increased endurance as measured by time to exhaustion – by increasing the use of fats as a fuel and thus sparing the stored carbohydrate (glycogen), particularly during the first 15-20 minutes.

Caffeine doses of between 3-6 mg/kg (1.4-2.7 mg/lb) of body weight taken 30-60 minutes prior to performance appear to not only enhance endurance performance but also strength and power performance as well as repeat sprint performance seen in team sports. When taken during exercise, a common practice in endurance athletes, recent research has shown no increased fluid loss during the performance.

Sodium Bicarbonate

Sodium bicarbonate (yep, good old baking soda!) has been shown to benefit performance in events requiring maximum effort lasting 1-7 minutes. This includes rowing and kayaking/canoeing events, 100-400m swim events, 400-1500m track events and track cycling events up to the 4000m pursuit. During such events, large amounts of lactic acid are produced in the working muscles. The increased acidity of the muscles leads to reduced energy metabolism and an inhibition in the ability of the muscles to contract effectively, thus leading to fatigue. Once produced in the muscles, the acid is pumped to the blood to be removed. The largest remover of acidity in the blood is bicarbonate found naturally in large quantities in the blood. Thus, ingesting more bicarbonate means a greater capacity to “buffer” the acid produced in the muscle and thus will assist in delaying fatigue and enhancing performance.

Sodium bicarbonate is taken at a dose of 0.3 grams/kg of body weight, mixed with 1-1.5 litres of water or diet cordial (to remove the terrible taste!) and drunk slowly 1-2 hours before the event. Another source is Ural available from chemists.

There appear no negative health effects of bicarbonate loading except the risk of gut upsets such as stomach cramps or diarrhoea. The IOC has not banned its use because of the wide range of normal values that exist in people. However, given the possibility of losing control over the bowels on the start line (not a pretty sight!), as with caffeine and creatine and any other supplement, try it in training or lead-up events to see how you respond.

Sodium Citrate

Like sodium bicarbonate, sodium citrate can reduce blood acidity and thus the body’s capacity to buffer the effects of lactic acid during hard exercise lasting between 2 and 15 minutes (kayaking/canoeing events, 200-800m swim events, 400-1500m track events and track cycling events up to the 4000m pursuit). The recommended protocol is a single dose of 0.4-0.5 gram per kilogram of body weight taken 60-90 minutes before events lasting longer than two minutes. Unlike sodium bicarbonate, it appears well tolerated by users with few gut upsets reported. Again, always try these things in training rather than at a major event.

Glycerol

Available at pharmacies as glycerine, glycerol is colourless, odourless, sweet-tasting syrup that has no effect on blood sugar or insulin levels. It has been shown in a number of research studies; including a published study we did on triathlon performance in hot and humid conditions, to store water (hyperhydrate) in the body. While some research suggest benefits for endurance athletes and others not, research conducted in hot and humid conditions suggests a benefit on performance through the hyperhydrating benefits.

Some athletes feel a sense of bloatedness when loading with glycerol. While it may not work for everyone, athletes preparing to compete may want to experiment with it. Research suggests a dose of 1-1.2 grams of glycerol per kilogram of body weight (0.45 gram / lb) in about 1-2 cups (273-473 mL) of water, low joule/calorie cordial (to give taste) or juice taken over 1.5 hrs prior to exercise.

Essential Amino Acids (EAAs)

There are nine essential amino acids the body cannot make itself and therefore must be consumed in the diet. Research has shown that EAAs have no ‘performance’ benefits but that using them before and after exercise increases the uptake of amino acids, thus enhancing muscle recovery after high intensity training. Researchers suggest taking 15 grams before training and no more than 20 grams after training with the effects enhanced by combining the EAAs with carbohydrate before training. Current recommendations are to consume 3-20 grams per day in combination with carbohydrate 30 minutes before training and a similar dose within 60 minutes of finishing training.

Branched-Chain Amino Acids (BCAAs)

The essential (body does not make them so must be found in the diet) amino acids leucine, isoleucine, and valine are collectively known as branched-chain amino acids and make up about 30% of the total muscle protein content. They are found in whey protein, milk, meat, fish and eggs and other quality protein sources. They are in high demand during endurance exercise as an energy source and are fundamental to repairing and building muscles after hard training.

Research has consistently shown that supplementing with BCAAs before, during and after hard training has reduced muscle breakdown, enhanced muscle repair and thus enhanced recovery time, and lead to improved mental performance during marathon runs. While supplementing with BCAAs does not directly benefit performance, the above benefits have been shown with dosages ranging between 9-15 gram total dose during exercise lasting 2 hours or more and 12 grams daily for 2 weeks may assist in enhancing recovery and reducing muscle damage following hard exercise.

B-Alanine

Very recent sports nutrition research has focussed on this substance (found in the diet in chicken and turkey) being used as a supplement. However, alanine itself does not have a performance-enhancing effect; it is alanine’s effect on a protein called carnosine that affects performance. Scientists have shown an increase of 64% in muscle carnosine after four weeks of supplementing with 4-6 grams per day of beta-alanine. Carnosine is found mainly in fast-twitch muscle where it helps buffer the effect of lactic acid produced during anaerobic work.

Glutamine

This is the most prevalent amino acid in the blood and found in large quantities in the muscle. It is used to make muscle and liver carbohydrate and assist in the building of muscle protein. In large doses (at least 20 grams per day) taken consistently over weeks, it has been shown to enhance muscle repair and immune function. Thus, it has been suggested as a useful supplement for athletes at risk of overtraining such as elite athletes undertaking regular high intensity training or recreational athletes doing regular high intensity or long duration training such as marathon runners or swimmers, road cyclists or triathlete’s training for long course or Ironman triathlons.

To enhance muscle and liver carbohydrate rebuilding, 8 grams of glutamine should be consumed immediately after exercise. For immune system and muscle repair benefits, 20 grams a day should be consumed immediately after exercise or in regular smaller doses over a day.