The dietary supplement and health food market is massive and is continuing to grow. To gain that extra edge it is not a surprise that athletes of all backgrounds find themselves drawn to additional dietary help to improve their physical output. Unfortunately, most of the supplements on shelves are not what they are made out to be and there is no substitute for good old-fashioned hard work. However, it is not all bad news, there are some foods and supplements that have been backed by science that can play a marginal performance enhancing role in sport and exercise.
Here we will briefly go over some of these health foods and supplements that may have a positive effect on performance directly. There are also many other dietary foods/supplements that claim to have an indirect on performance such as aiding recovery, assisting muscle development or improving immune function which we will not go into detail.
Caffeine:
One of the most commonly used supplements and widely used legal drug (in the form of coffee). There is significant scientific for caffeine as a positive performance enhancement for some athletes in range of different types of activities.
Possible benefits are improved endurance capacity such as exercise time to fatigue and time-trial activities of varying duration (5-150min). This has been shown across activities such as cycling, running, rowing and various team-sports. Improvement in performance measures such as time-trial time have shown to range from 3-7%.
How does it work?
Caffeine is a stimulant which can enhance vigilance and alertness, perception of fatigue and exertion during exercise and improve neuromuscular function. It can also stimulate an endorphin release which can assist in feelings of wellness.
A systematic review by Ganio et al (2009) has shown 3-6mg/kg of body mass consumed 60 min prior to exercise is sufficient to provide positive effects. However lower doses <3mg/kg of body mass has shown to also be effective. To put that in perspective the average cup of coffee has about 100mg of caffeine in it.
Possible side effects:
Larger doses of caffeine have shown not to further increase performance enhancement and in fact increase likelihood of negative side effects.
Possible side effects include; nausea, anxiety, insomnia and restlessness. Caffeine is also a diuretic which can increase urine flow but is small when consumed at the doses that have shown to improve performance.
Sodium Bicarbonate:
Sodium bicarbonate is a commonly occurring substance in most foods. In fact, most households will have this In their kitchen without even knowing as it is commonly known as baking soda.
How does it work?
It helps regulate PH in the blood which commonly increases in acidity during exercise. Sodium bicarbonate is naturally occurring in the body and helps buffer excess acid that accumulates during bouts of high intensity exercise. By keeping muscle PH level closer to its normal it can enhance exercise capacity.
Sodium bicarbonate has shown to enhance performance during short term, high-intensity exercise of approximately 60s in duration of approximately 2%. Improvements reduce as duration of effort exceeds 10 min.
Protocol of use:
According to the evidence various strategies of consumption have been suggested.
1. Single dose of sodium bicarbonate of 0.2-0.4 g/kg of body mass, 60-150 mins prior to exercise
2. Split dosage (i.e multiple smaller doses totalling 0.2-0.4 g/kg) over 60-180 min
3. Serial loading with 3-4 smaller doses per day for 2-4 days consecutive prior to an event
Potential side effects:
It is well established that gastro-intestinal upset can be associated with sodium bicarbonate. Therefore, may not be appropriate for some athletes or ideal consumption strategies may be person dependant.
Creatine:
Creatine is naturally occurring substance in body where it is found in the substance creatine phosphate. Its use as a supplement has grown significantly over recent times. Creatine works by aiding resynthesis rate of the phosphocreatine energy system. In short aiding the use of the energy system in the body that is utilised in short, high-intensity bouts of exercise.
In term creatine has shown to have positive effects particularly in sports that involve repeated high-intensity exercise (eg. Most team sports). it has also shown to assist in increased gains of lean mass and muscle strength and power.
Potential side effects:
No negative health effects are noted with long-term use (up to 4 years) when appropriate consumption use is followed. However, a 1-2 kg of body mass increase has shown to be a possible side effect which is primarily the result of water retention. This is an important consideration as the possible detrimental effect of increase weight gain may outweigh the positive effect of creatine.
Nitrate or Beetroot Juice:
It may seem as an odd one to add in but nitrate which is readily found in beetroot has been shown to have positive performance enhancing benefits. High nitrate rich foods include leafy green and root vegetables, including spinach, rocket, celery and of course beetroot which accounts for one highest sources of nitrate.
How does it work?
Nitrate contributes to the production of nitric oxide in the body. Nitric oxide is a vasodilator which improves blood flow and oxygen delivery to muscles. It therefore can improve the muscle efficiency in utilising oxygen and can improve the performance and energy efficiency of type 2 or fast twitch muscle fibres.
Supplementation of nitrate has been associated with improvements of 4-25 % in time to exhaustion during exercise and 1-3 % in sport specific time trial events lasting less than 40 mins.
Protocol of use:
Nitrate consumption within 2-3 hours of activity as bee associated with improved performance. Prolonged use of nitrate also appears to be beneficial and has been suggested strategy for highly trained athletes where improvements from nitrate supplementation is smaller.
Potential side effects:
There appears to be few side effects or limitations to nitrate supplementation. It is suggested that there is potential of gastro-intestinal upset and therefore suggested to be trialled in trainings before the use in competition. It also appears that performance gains and harder to obtain in highly trained athletes.
Beta-Alanine:
A naturally occurring amino acid, beta-alanine plays a role in the development of a carnosine.
How does it work?
Similar to sodium bicarbonate, carnosine acts as a acidity buffer in the muscle and therefore helps maintain an optimal PH level for muscular performance. It helps resist muscle fatigue and in term potentially assists performance.
Protocol of use:
Beta-alanine is commonly found in meat, poultry and fish and therefore most people can get enough beta-alanine through their regular diet.
Dietary supplementation however can further assist our daily intake. It is suggested a daily consumption of 65mg/kg of body mass taken in 3-4 smaller doses throughout the day.
Potential side effects:
Possible side effects include skin rashes and/or transient paraesthesia (tingling feeling in the skin) when taken with high single doses. This effect is temporary and harmless.
It should also be noted the effectiveness of supplementation appears to be harder to realise in well-trained athletes.
It should go without saying please seek professional medical advice whenever considering whether additional dietary supplementation is right for you.
If must also be noted that inadvertently consuming a known banned/prohibited substance should be risk considered when weighing up the decision to pursue dietary supplementation. Please find some useful links below which can assist in determining whether a specific product is considered banned or has gone through the necessary batch testing to determine if it is safe for consumption under the anti-doping rules.
Useful resources:
https://www.informed-sport.com/
https://www.asada.gov.au/substances/check-your-substances