Facilitate digestion, fight against stress and fatigue, boost the brain, sunbathe or promote sleep: the promise of food supplements seems endless. While some substances have a real benefit, others are perfectly useless or even dangerous. How to find your way around?
Not subject to the same obligations as drugs, food supplements are not necessarily harmless substances. Some may even be harmful to health or cause side 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 fill a food deficit, reduce or eliminate daily discomfort (difficulty falling asleep, joint pain …) or maintain a state of general good health (bone strengthening, weight control …). In theory, a balanced diet is enough to cover all our needs. In practice, however, food supplements are often used to compensate for an unhealthy lifestyle, which is not their original purpose. On the other hand, no link has yet been proven between consumption of vitamins or minerals and reduction of diseases. On the other hand, they can be interesting for certain categories of population, like vitamin B9 in pregnant women whose deficiency can lead to abnormalities in the fetus, or vitamin D in the elderly.
Read the composition well
Not all food supplements are created equal. For the same indication – probiotics promoting immunity for example – the quantity of bacteria can vary from one to ten in a capsule, the tablet contains more or less different strains and the list of ingredients is more or less long. The dosage form (sachet to dilute, 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 at half the price may be half the dosage, which will cost the same price as a box of 30 capsules twice the dosage. Beware of excipients (bulking agents, colorings, added sugar and sweeteners, synthetic flavors …) which can be allergenic. Favor natural and organic formulas; Vitamin E exists for example in natural or synthetic form (sometimes labeled gamma-tocopherol).
One tablet for sunbathing, one for better sleep, one for tone … In total, some people manage to swallow several tablets per day. “The multiplication of concomitant cures, in particular containing the same active ingredients can lead to overdoses or interactions”, warns the Synadiet himself. According to a Nutrinet study, 7% of consumers have taken that can be described as “at risk”. Most of the time, the superfluous substances are excreted in the urine, like vitamin C. However, “the elimination of the surpluses can harm the liver or the kidneys”, warns the magazine 60 million consumers. Liposoluble vitamins like vitamin A and D are not eliminated in the urine. Continuous and excessive intake can therefore lead to hypervitaminosis. Patients with diabetes or hypertension should also take into account the salt or sugar content of food supplements. Products based on algae or crustaceans (against joint pain for example) are often very rich in salt.
Beware of health claims
“Anticancer”, “Immediate and effortless weight loss”, “Cleans the body” … A dietary supplement can carry a health claim provided you provide scientific evidence, as well as functional foods like margarines enriched with omega 3. Two types of claims are authorized: those of a nutritional type (“rich in fiber”) or those relating to its health benefits (“magnesium helps reduce fatigue”). However, therapeutic (“cures the flu”) or misleading (“100% of daily requirements” but relating to 100 g of product and not to a tablet) are banned. However, the effects remain to be put into perspective. To have the protein equivalent of a beef steak, you would have to consume for example 35 g of spirulina, or about 15 tablets! In summary: do not believe in miracle claims. “Food supplements have effects but are not drugs, they are involved in prevention,” insists nutritionist Jean-Michel Lecerf.