Facilitate digestion, fight against stress and fatigue, boost the brain, get a tan or help you fall asleep: the promises of food supplements seem endless. If some substances have a real benefit, others are completely useless or even dangerous. How to find your way around?
Not subject to the same obligations as drugs, food supplements are not harmless substances. Some of them can even be dangerous for your health or cause undesirable effects. Between marketing arguments and real promises, here is what you need to know to use them properly.
Food supplements: do we really need them?
Some 46% of French people consume or have already consumed food supplements, according to Synadiet, the union of manufacturers of food supplements. A dietary supplement is used to make up for a dietary deficit, to alleviate or eliminate a daily discomfort (difficulty falling asleep, joint pain…) or to maintain a state of general good health (bone strengthening, weight control…). In theory, a balanced diet is sufficient to cover all our needs. In practice, however, food supplements are often used to compensate for a poor lifestyle, which is not their initial purpose. Moreover, no link has yet been proven between the consumption of vitamins or minerals and the reduction of diseases. On the other hand, they can be interesting for certain categories of population, such as vitamin B9 for pregnant women whose deficiency can lead to abnormalities in the fetus, or vitamin D for the elderly.
Read the composition carefully
Not all food supplements are the same. For the same indication – probiotics promoting immunity, for example – the quantity of bacteria may vary from one to ten in a capsule, the tablet may contain more or less different strains and the list of ingredients may be more or less long. The galenic form (sachet to be diluted, capsule or tablet) itself influences the absorption of the active substances and their bioavailability. Read the composition of the labels carefully: a box of 60 capsules sold for half the price may be half the dosage, which will be the same price as a box of 30 capsules with twice the dosage. Beware of excipients (fillers, coloring agents, added sugar and sweeteners, synthetic flavors …) that can be allergenic. Favour natural and organic formulas; vitamin E exists for example in natural or synthetic form (sometimes labelled gamma-tocopherol).
One tablet for tanning, one for sleeping better, one for tonus… In total, some people end up swallowing several tablets a day. “The multiplication of concomitant cures, in particular containing the same active ingredients can lead to overdoses or interactions”, warns the Synadiet. According to a Nutrinet study, 7% of consumers have intakes that can be qualified as “at risk”. Most of the time, the superfluous substances are evacuated in the urine, like the vitamin C. However, “the elimination of the excess can harm the liver or kidneys”. Fat-soluble vitamins such as vitamin A and D are not eliminated in the urine. A continuous and excessive intake can thus lead to a hypervitaminosis. Patients with diabetes or high blood pressure must also take into account the salt or sugar content of food supplements. Seaweed and shellfish products (for example, for joint pain) are often very high in salt.