Supplements may not be what you expect them to be

A nutrition supplement is, as the name indicates, supposed to “supplement” the diet, not replace the diet or become the main goal. First the diet needs to be addressed and a solid foundation needs to be built. Once the diet is in order, we can add sports nutrition foods if needed and supplements should be the icing on the cake, the tip of the pyramid or the roof of a house that is built on a solid foundation. 40-70% of athletes take supplements (1), do they all have their foundation sorted?

Definition of supplement

For most purposes, sports drinks, energy bars, gels, and other sports foods are excluded from the definition of supplements, although the use of these products is widespread in sport. These products are referred to as sports foods. With supplements we refer to the pills, the capsules, the herbal preparations and other products that come in small pots, often contain a lot of (sometimes pretty wild) claims and have little or no evidence to back up those claims.

Supplements may not be what they seem Supplements were in the news (*) recently because an investigation into supplements sold at major retailers in the USA, were found to be well below the standards. Only in 1 out of 5 products contained what the label promised. Some supplements in this investigation did not contain anything at all (other than fillers).

Supplements may contain more than you bargain for While you may not find the substance you thought you bought in the product, you may find other substances in it. Some of these substances might be on the list of banned substances, some could potentially be dangerous. The issue of contamination of supplements is real, many products are affected and quality control is not always what it should be. The contamination may be inadvertently, but there are also cases where drugs, sometimes designer drugs were added to make a product more effective and this was of course not declared on the label. As mentioned before, 40-70% of athletes take supplements, 10-15% of supplements are contaminated.

Evidence base Even if a supplement contains what it says on the label and is produced with high quality control standards, it may not actually do what it says it does. Labels sometimes contain impressive claims, but the truth is that very few of the estimated 55,000 supplements on the market actually have an evidence base. Often the claims are far fetched extrapolations. For example if a study in test tubes shows the effects of substance A on the production of substance B in the body and substance B is linked with muscle growth, it does not mean that giving supplement A to humans, it will make them bigger. Humans are different than cells. Maybe substance A cannot even be absorbed (which is the case for numerous supplements on the market) or maybe it was used in amounts that you will never find in a supplement (true fore a very large number of supplements). Maybe there is only one study in humans, maybe the study was done by the producers of the supplement? In that case the results should be replicated independently and confirmed by other researchers. This is a lot of work and it is extremely costlyand time consuming and therefore it usually does not happen.

What to do

So back to diet. A well balanced and varied diet should contain everything even an elite athlete would need. As always, there are a few exceptions. For example iron supplementation is warranted in some cases, but such situations need to be assessed by trained people. So my advice would be to work with a registered dietitian to establish a healthy diet and ask for advice when taking supplements from qualified people.


1. Outram and Stewart Int J Sport Nutr Exerc Metab 2015, 25: 54-59.

#supplement #performance #healthydiet


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