The role of supplements in sports performance: My insights

FitPro’s resident dietitian Dr Linia Patel (Phd), RD gives you her take on three of the most common supplements in the sports world, as she explores the role of supplements in sports performance.

As a performance dietitian, I spend a significant amount of time discussing nutritional supplements with clients – what they’re taking, what works and what doesn’t. Over the years, I’ve noticed some common patterns. Firstly, many active people take multiple supplements in search of a ‘magic bullet’. While some supplements can be beneficial, they’re often taken in incorrect doses, at the wrong times or in inappropriate cycles, leading to frustration when they don’t seem to work. Additionally, the placebo effect is powerful; even supplements with little scientific backing can appear effective if someone strongly believes they will work. While food should always come first, supplements do have their place. Here’s my take on three of the most common supplements in the sports world.

1. Caffeine

Caffeine is more than just your morning coffee; it’s been used by endurance athletes for years to help them push through by reducing perceived effort.

The science

Studies show caffeine can improve endurance performance by up to 7%, depending on the sport, exercise duration and the individual. A meta-analysis of 56 time trials found up to a 15.9% improvement with caffeine, especially in longer trials. This effect is likely because caffeine targets brain systems related to fatigue and pain, which intensify with prolonged exercise. Optimal doses range from 3-6mg per kg of bodyweight, with no added benefits above 9mg/kg. This means a 60kg female would be looking to have 180-360mg of caffeine. For reference, an espresso contains about 50mg. If you are looking for caffeine as a supplement, it is recommended you use caffeine tablets, for example, rather than coffees. Higher doses can lead to anxiety, gastrointestinal issues and irregular heartbeats. Most sports can benefit from caffeine, particularly longer aerobic activities. However, the International Olympic Committee (IOC) consensus is that, particularly for intermittent type of activities (i.e., team sports), the effects of caffeine on mental performance and cognition are not superior to a good night’s sleep.

My verdict

I’m a big fan of caffeine for endurance athletes, although individual responses vary. Some people feel more alert and energised, improving their endurance and speed, while others may experience jitters, a fast heart rate or digestive issues. For those who benefit, caffeine is best consumed 30-60 minutes before activity. Test your response during training, not on race day, and remember that caffeine can stay in your system for up to six hours, potentially affecting sleep.

2. Creatine

Creatine is one of the most popular and well-researched supplements, known for enhancing high-intensity exercise capacity and increasing lean muscle mass. Recent evidence also suggests potential brain and health benefits.

The science

Creatine monohydrate enhances adenosine triphosphate (ATP), the primary energy source for muscle contractions. By increasing the availability of ATP, creatine monohydrate may delay the onset of fatigue and allow endurance athletes to sustain higher intensities for repeated efforts in training. This in turn translates into increase muscle contractions and delayed fatigue, allowing endurance athletes to maintain higher intensities during training. It has been shown to improve muscle power and strength, even in endurance athletes, and aids in recovery from intense exercise. For best results, take 5g of creatine monohydrate daily. It usually takes at least 28 days of consistent use to increase creatine stores and experience benefits, which can last for two to six weeks.

My verdict

I’m a strong advocate for creatine, although individual responses vary. Factors like genetics, training status, diet and baseline creatine levels all play a role. Some people may experience gastrointestinal discomfort, especially at higher doses or when not fully dissolving it in water. Stick to recommended dosages and consult a healthcare professional if you have pre-existing kidney conditions.

3. Beetroot

Athletes are increasingly turning to nutrient-dense foods like beets to boost performance. Beetroot juice, rich in vitamin C, antioxidants and nitrate, has become a popular supplement for improving athletic performance.

The science

Nitrate-rich vegetables like beets can enhance athletic performance by increasing nitric oxide levels in the body, which improves blood flow, lung function and muscle contraction. These benefits contribute to better cardiorespiratory endurance and performance. Research suggests consuming 70-500ml of beetroot supplement for the best results, equivalent to about two cups of juice or 384g. Concentrated beet shots typically contain 400ml per 70ml shot.

My verdict

If you want to use nitrates, it’s important to be consistent to allow the levels of nitric oxide to accumulate in your body. While dietary nitrates can improve blood vessel dilation and potentially enhance endurance performance, research indicates sex differences in response to nitrate supplementation. More studies on women are needed to fully understand these effects.

References

1. Mieglo-Ayuso J et al (2019), Effect of Caffeine Supplementation on Sports Performance Based on Differences Between Sexes: A Systematic Review, Nutrients, 11(10): 2,313.
2. Sun et al (2022), Effects of caffeine ingestion on physiological indexes of human neuromuscular fatigue: A systematic review and meta‐analysis, Brain and Behaviour, 12(4): e2529.
3. Antonio J et al (2021), Common questions and misconceptions about creatine supplementation: What does the scientific evidence really show? J Int Soc Sports Nutr., 18(13)
4. Rawson E et al (2018), Dietary supplements for health, adaptation and recovery in athletes, Int J Sport Nutr Exerc., Metab, 28(2): 188-199.
5. Candow D et al (2023), Heads up for creatine supplementation and its potential application for brain health and function, Sports Med., 53(Suppl 1): 49-65.
6. Lopez et al (2009), Does creatine supplementation hinder exercise heat tolerance or hydration status? a systematic review with meta-analyses, J Athl Train., 44(2): 215-223.
7. Dominguez R et al (2017), Effects of Beetroot Juice Supplementation On Cardiorespiratory Endurance in Athletes, A systematic review, 9(1): 43.

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