What you take can actually be detrimental to your body. – By Dr Ross Tucker

There’s a product on the supplement market called ‘Sweet Sweat’: it’s a cream that you rub on your body before you exercise, and supposedly, it causes the temperature of your skin and muscles to rise, which helps you burn more fat when you train. It comes in a little black jar, and the label has a very scientific-looking thermal image of a body on it, half of which is covered in Sweet Sweat and is an intense shade of red; the other half is light green, to illustrate the side on which the cream hasn’t been used.

I’d like to think that nobody would be gullible enough to fall for such a claim; but I suppose the fact that it’s there on the shelf in the first place means there’s a market for it, and that I may be underestimating how gullible people can be!

THE EVIDENCE

The supplement industry is a law unto itself. Sweet Sweat is one of thousands of supplements you can buy, all of which promise miracle results – but virtually none have any evidence supporting their claims of effectiveness. In fact, the consensus among experts in nutrition science is that the only supplements with any proven benefit are carbohydrates for energy, creatine (for some people), caffeine, and bicarb (for high-intensity exercise, because it acts as a buffer).

For all the rest, there is either weak or no evidence of benefits – and in some cases, evidence that the supplement doesn’t work, or can be detrimental. For instance, high doses of anti-oxidants may be detrimental to exercise, because they may actually block the steps that are necessary for exercise to be beneficial.

One of the most important benefits of exercise is that it improves our body’s ability to process glucose. Taking high doses of anti-oxidants wipes this benefit away. One study found that both trained and untrained people who took high doses of Vitamins A and C benefited from exercise less than those who took a placebo pill.

Another supplement, resveratrol, is supposed to have a number of benefits for the heart, liver and cells; but it too seems to blunt the body’s positive adaptations to exercise.

In this instance, people who took the supplement had impaired vascular function, worse blood-lipid profiles (such as cholesterol), and their fitness improved less than in people who took a placebo.

In other words, if you’re training for fitness and health, the very supplements that are sold to you for health may actually be compromising yours.

RISK VERSUS REWARD

Even worse: supplements can be downright dangerous. Between 2004 and 2013, 63 hospital emergency wards documented 23 000 admissions for supplement-related complications.

That’s almost one a week per hospital. Most of them were for palpitations, chest pain and heart problems, and almost three-quarters were users of weight-loss supplements – which often contain stimulants.

Those can on occasion be fatal: during the London Marathon a few years ago, a 30-year-old woman collapsed and died less than two kilometres from the finish line. A coroner ruled her death the result of a stimulant found in a supplement she had taken, combined with physical exertion. That supplement is now banned; but many others contain the same ingredient.

The bottom line: with very few exceptions, supplements probably don’t work, and may be dangerous. If you put that into a calculation of risk versus reward, it doesn’t look good at all – all risk, little reward. This is the reason why all the consensus statements say you should address your diet first.

Certainly, in some cases – huge training loads, people who are indoors all the time, women, those with restricted diets – some supplements may be advisable, and it’s worth considering those in consultation with a dietician. But for most of us, when we over-consume or rely on supplements, it detracts from where the real gains are to be found.

RW Scientific Editor Dr Ross Tucker has a BSc (Med) (Hons) Exercise Science Degree and PhD from the Sports Science Institute. Visit him at www.sportsscientists.com.

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