Sports supplements: Are they worth all the hype?!

Sports nutrition continues to boom with interest in sports supplements extending beyond athletes and body builders. Your everyday gym goer wants to be lean and strong; strength has become a greater priority than the figures on the scales. There is a surge in fitness and health bloggers with their photos on Instagram and Facebook creating a desire and motivation to achieve a leaner body. Non-professional sports are becoming more and more competitive and individuals are increasingly more open to taking supplements in hope they will gain an added edge.

Although there is continued research and funding to show a given supplement can improve body composition or performance, very few supplements have been shown to be effective. Those that show effectiveness are often based on research conducted on a small number of male athletes (such as cyclists) and therefore, how can we be convinced that this will work for everyone?

Below are my top 5 supplements that have the most robust evidence and a good safety profile, but of course there is no substitute for disciplined training and a proper diet!

  1. Creatine:

Creatine phosphate is stored in your muscles and provides an excellent store of energy for very high intensity exercises (when oxygen supply to the muscles is insufficient). You will be using your creatine phosphate stores when you do an “all-out sprint” or lift maximum weights. Both of these examples cannot be maintained for very long and this is because the creatine phosphates are spilt to produce energy and they must be recycled. The recycling process requires oxygen so you will need to get your “breath back” in order to make more creatine phosphate.1

We consume creatine via meat and fish products and we can also make it in the liver; both of which amount to about 2g/day.  An average (70kg) athlete stores around 120g of creatine. Supplementation studies have shown that muscle creatine concentration can be increased by up to 20% using creatine supplements.2

This is achieved by creatine loading: 2

  • Consume 20-25 g/day of creatine over 5-6 days followed by 2g/day as maintenance or
  • Consume smaller amounts (around 3g/day) over 1 month.

Improvements in performance have been shown in weight lifters who loaded with creatine. Creatine supplementation can also cause weight gain (1-2 kg increase in total body mass has been documented after 20g/day loading with creatine for 4-28 days).2 Supplementation increases intracellular water in the muscle which may stimulate glycogen storage. However, there are responders and non-responders; it does not work for everybody! Lastly, anyone with kidney disease should avoid creatine supplementation as it may affect creatinine clearance.

Summary: Creatine supplements may allow maintenance of top speed/strength for longer but this does not always equate to improved performance.

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  1. Caffeine

Caffeine is a socially acceptable stimulatory drug. Caffeine can improve performance in endurance exercises such as running and cycling and also in high intensity sports such as rugby and soccer (from 1 to 3%).3 Caffeine is a central nervous system stimulant and works by reducing an athlete’s perception of effort and/or pain threshold.2 It has been used as an adjunct to weight loss but caffeine alone has not been shown to have an substantial effect on weight loss.  Unless you are already dehydration, caffeine has not been shown to negatively impact hydration status. Caffeine tends to work when 1-3 mg per kg body weight is consumed before or during exercise.4 A typical cup of coffee contains 80-100 mg of caffeine. You can also take caffeine supplements but if you drink coffee then you can just get your caffeine hit with coffee!

Caffeine is considered safe but excess (greater than 500 mg or greater than your own tolerance level) causes side effects such as increased blood pressure at rest and during exercise, increased heart rate, gastrointestinal distress and insomnia. Caffeine addiction has been documented with doses as low as 100 mg/day and sudden withdrawal can result in severe headaches, drowsiness, and inability to concentrate.1

Personally, I find a cup of coffee (although not a supplement!) before a run or the gym great for a boost but I do not take it before a competitive match because coffee heightens any nervousness I already have coming up to a game!

Summary: Caffeine can improve performance as it is a nervous system stimulant but in excess/above personal tolerance it can cause gastrointestinal distress, increased heart rate and insomnia.

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  1. Protein

The benefit of protein supplementation is more down to convenience than anything else! Protein supplements can be helpful for those going from work to training, or when it may not be possible to have a descent meal soon after training or for those with very high protein requirements; but protein supplementation itself is not more or less effective for increasing muscle mass than protein from food.2  Whey protein is a “fast acting” protein that is absorbed easily and therefore, its amino acids such as the branched chain amino acids- leucine, isoleucine and valine are quickly taken up by muscles. Ricotta cheese contains the highest amount of whey of any wholefood because it is made from whey protein. Casein is a “slow acting” protein with slower absorption compared to whey protein but it provides a more sustained rise in amino acids which may help supress muscle breakdown. Milk contains around 20% whey and 80% casein but all dairy products will contain a mixture of whey and casein. Milk is also rich in leucine which can minimise protein breakdown and is the only amino acid that by itself can stimulate protein synthesis! Research on other individual amino acids is mixed.2 For more on protein please read my recent blog what and when to eat to optimise sports performance

Summary: Protein supplements can be beneficial in enhancing muscle growth and recovery but has not been shown to be more superior to protein from food sources.

  1. Beetroot

Beetroot, spinach, rocket, carrots and most root vegetable contain nitrates. Nitrates can be converted in the body to nitric oxide which improves blood flow via vasodilation. Nitrate intake has been associated with enhanced exercise performance.1 A study by Murphy et al. in 2012 showed that whole beetroot consumption improved running time in 11 recreational fit men and women who ran 5km compared to those who consumed cranberry relish (12.3±2.7km/hr versus 11.9±2.6 km/hr).5  Furthermore, during the last 1.8 km of the 5-km run, running velocity was 5% faster (12.7±3.0 vs 12.1±2.6 km/hour; P=0.02) in the beetroot group. Although beetroot is a food and not a supplement it is worth a mention as the results have been very positive. Perhaps you could have a beetroot, spinach and carrot based smoothie pre-training!

Summary: Consumption of beetroot or an equivalent nitrate dose from other vegetables improves running performance in healthy adults.5

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  1. Probiotics

Athletes with prolonged, intense training often experience diarrhoea and upper respiratory tract infections. This is because vigorous exercise increases gastrointestinal permeability causing ‘leaky gut’. In 2011 West et al. showed that supplementation with a probiotic called Lactobacillus fermentum reduced the severity of self-reported symptoms of lower respiratory illness, use of cold and flu medication, and severity of gastrointestinal symptoms at higher training loads in Australian male athletes.6 Although this research was specific to male Australian athletes it may be worth a trial of this strain if you experience re-occurring diarrhoea and/or respiratory tract infections.

Summary: Athletes experiencing diarrhoea may benefit from a trial of probiotic bacteria called Lactobacillus fermentum.

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References:

  1. Dunford, M. & Doyle, J.A. (2015). Nutrition for sport and exercise. (3rd edition) Stamford, CT: Cengage:
  2. Helms et al (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition, 11:20
  3. Noakes, T.M. (2002). Love of running (4th Ed). Champaign, IL: Human Kinetics
  4. Burke, L.M. (2008). Caffeine and sports performance. Applied Physiology, Nutrition, and Metabolism, 33, 1319-1334.
  5. Murphy, M. et al. 2012 Whole Beetroot Consumption Acutely Improves Running Performance. Journal of the Academy of Nutrition and Dietetics 112;4:548-552
  6. West N.P, et al. (2011) Lactobacillus fermentum (PCC®) supplementation and gastrointestinal and respiratory-tract illness symptoms: a randomised control trial in athletes. Nutrition Journal, 10:30