Sports supplements: are you getting real gains or just a placebo effect?

Andrew Hamilton looks at new research on the power of the placebo effect in sports supplements

It’s long been known in medicine that the power of positive suggestion can provide a real and significant improvement in symptoms. This is the so-called ‘placebo effect’, where the mere belief that a medicine or some other form of treatment will provide benefits can actually produce some benefits. And these benefits can be had even if that treatment is nothing more than a sham – a completely inert substance that could not possibly benefit the patient in any physiological way. Unfortunately, many people fall victim to the placebo effect – spending large amounts of money on products where there is no real evidence of any benefit. Because of the placebo effect, they feel better, but this is purely down to their beliefs about the product rather than any physiological benefit.

Overcoming the placebo effect

It’s precisely because of the placebo effect that doctors and scientists need to investigate the potential benefits of medicines (or other products such as sports supplements) using carefully controlled studies. This means that alongside the medicine, supplement or any other kind of intervention, a control group is used – a group of subjects who go through the same experimental protocol but instead of using the potentially beneficial medicine/treatment, they are told they’re getting the same treatment but are instead given a completely inert placebo – a sham treatment. Because both groups of subjects experience the same placebo effect, you know that any significant difference in outcomes between the ‘real’ group and the control group is not down to the placebo effect, but down to actual benefits provided by the treatment.

Brain power and placebo

That the brain and our belief systems can have a profound effect on the way we feel and perform is becoming ever more apparent as new studies show. For example, studies on endurance athletes show that when your mood state is elevated by the use of music, you can exercise at a higher intensity but your perception of effort doesn’t change. Likewise, expectations and beliefs can affect your performance. For example, runners who are told that they will be completing 10km run experience a sudden jump in perceived effort if, 5kms into that run, they are told that the run distance is not 10km but is in fact 20km [Appl Physiol Nutr Metab. 2011 Feb;36(1):23-35].

Also, other studies have shown that you can boost performance by ‘fooling’ the brain. In one study, cyclists were deceived by researchers. The cyclists – without access to any indication of their speed – thought that the time trial speed set by researchers was equivalent to their best time trial speeds. However, the researchers had actually set it 2% faster. Of the 14 cyclists in the study, 10 significantly improved their performance over their theoretical best times [Int J Sports Med. 2016 May;37(5):341-6]. This showed that by fooling the brain into thinking that the body was working no harder (when it was), many of the cyclists were able to squeeze out a little more performance!

Placebo – why the mouth matters

The placebo effect is undisputed among scientists, but now new research by German scientists suggests that for athletes, the type of supplement and the way it interacts with the mouth can also affect how much placebo effect is generated [PLoS One. 2018 Jun 11;13(6):e0198388. doi: 10.1371/journal.pone.0198388. eCollection 2018]. In this study, the researchers compared three scenarios to see whether the type of placebo given affected performance. Thirty four athletes performed three time trials on a cycling ergometer in identical conditions. However, what they took beforehand differed:

  • No placebo – ie nothing given.
  • An inert placebo consisting of small capsules containing four grams of amino acids (note that no study has ever shown that such a small amount of amino acids given prior to exercise boosts performance).
  • A vanilla-grapefruit flavoured pudding containing the same amount of (inert) amino acids plus fibre and water.

To reiterate, none of the athletes received anything that could boost physiologically performance. In effect, this was a no-placebo vs. a discreet placebo vs. a much more interactive placebo (the pudding) test!

The results

The results showed that compared to taking the placebo as capsule or taking no placebo at all, when the cyclists consumed the placebo pudding, their performance improved significantly, even though their subjective levels of effort didn’t. In other words, the type of placebo used affected performance – even though none of placebos contained anything known to enhance performance!

How and why was this the case? The researchers put it down to the ‘high salience’ characteristics of the pudding. This pudding contained ingredients that stimulated both bitter and sweet taste receptors in the mouth. It also contained a small amount of cornstarch, which is known to stimulate carbohydrate receptors in the mouth. This pre-exercise mouth receptor stimulation may help to slightly ‘decouple’ the normal relationship between perceived exertion and actual exercise intensity. The low-salience capsules meanwhile offered no such receptor stimulation – they were just swallowed with water. Further evidence for this theory comes from the fact that the athletes’ belief concerning the true nature of the ergogenic aid (inactive placebo vs. ergogenic supplement) did not influence the ergogenic placebo response – in other words, these gains were as a result of the placebo effect, but instead of being ‘belief driven’ were ‘mouth receptor’ driven.

Real versus placebo effects

Of course, while it’s great to trick the brain and try and maximise any placebo effect, an even better way to guarantee enhanced performance is to use proven ergogenic supplements such as caffeine, creatine and good old carbohydrate! These kinds of supplements have been tested using controlled studies and shown to produce a significant uplift in performance, above and beyond any placebo effect. With that in mind, the articles below are essential reading for any runner, cyclist, triathlete or swimmer who wants to guarantee maximum performance on the day – not just hope for it with a placebo effect!

Andrew Hamilton, Sports Performance Bulletin editor

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