In Italy the supplement market is growing year after year. They exist for every need, from those to strengthen the immune system to those that promise to counteract the feeling of hunger but studies on their actual effectiveness say otherwise. Luca Pasina, head of the Clinical Pharmacology and Appropriateness laboratory of the Department of Health Policies of the Mario Negri Institute, explains why supplements are almost always useless, and sometimes even risky.
Interview with Luca Without
Head of the Clinical Pharmacology and Appropriateness laboratory of the Department of Health Policies of the Mario Negri Institute
The market of food supplements in Italia is the first in Europe: from 2013 to 2023 the consumption grew by 60%, going from 125 million packs sold in 2013 to around 200 million in 2023. The data released by Integratori & Salute, the national association representing the sector, confirm a trend that is difficult to deny: Italians are large consumers of supplements, and after Covid-19 have become even more so.
Per strengthen immune defensesto feel less tired, to have healthier hair or nails, but also to combat the feeling of hunger and have “help” during a slimming diet: even if you want to list them all, it is difficult to exhaust the list of reasons so we take supplements. Yet in the scientific literature there is not enough evidence of the effectiveness of using supplements, unless there are objective and certified needs. And even in these cases several persist doubts about their usefulness. On the contrary, the possibility has been reported, especially in DIY use, of incurring several health risks.
At Fanpage.it we have tried to clarify the usefulness and risks of supplements with Luca Withouthead of the Clinical Pharmacology and Appropriateness laboratory of the Department of Health Policies of the Mario Negri Institute.
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Italy is one of the main consumers of supplements in Europe: are there any categories of supplements that we could definitely define as “useless”?
I would say the totality: most users believe that these products are safe and free of side effects, but only rarely are studies available that have evaluated the effectiveness, side effects and potential interactions of these products. Several scientific works on the topic conclude that although the supplement market is continually growing, the emphasis and expectations are not supported by scientific data.
Many people take them to combat the feeling of tiredness, because they think they have vitamin deficiencies. They hurt?
The point is not about the fundamental role of vitamins, but about the effectiveness of the supplements that promise to integrate them. There is in fact no doubt that vitamins and some antioxidant substances are necessary for the correct functioning of the organism and that their deficiency must be corrected, but there is no scientific evidence that documents the benefit of an extra intake in the form of supplements. The available data suggest, on the contrary, that the chronic use of these products is not without risks.
So we have no scientific confirmation of their usefulness, but can we at least be confident that we won’t risk anything by taking them?
In general, the health risks are thought to be low. However, a study conducted in the United States in 2015, published in the New England Journal of Medicine (NEJM), estimated that supplements are responsible for approximately 23,000 emergency room visits each year.
What supplements were taken in these cases?
The majority of emergency room visits in the adult population have been attributed to products used to reduce appetite, increase stamina, muscle mass, and improve sexual performance. These products have often caused heart problems (palpitations, chest pain and/or tachycardia) and neurological/psychiatric disorders (headache, dizziness, motor difficulties and anxiety).
And what should those who take them to strengthen their immune defenses know?
There is no convincing evidence and no studies have documented benefits for people taking these supplements.
Multivitamin supplements are also widely used. He explained to us that there is no evidence of their usefulness, but are there any risks?
Let’s start from the lack of benefits: some studies have clearly shown that the constant supplementation of multivitamins and mineral salts is not associated with any protective effect on mortality, risk of tumors or cardiovascular diseases. This means that no reduction in these three parameters was observed. On the contrary, their hiring did not prove to be risk-free.
What has emerged from the studies conducted so far on their safety?
The excess of some fat-soluble vitamins, for example, can lead to toxic effects: some studies have in fact observed a small increase in mortality associated with the regular consumption of beta-carotene and vitamin E, suggesting that the use of these supplements in the absence of evident nutritional deficiencies does not offer appreciable advantages, but only involves possible risks.
Furthermore, other studies have observed that the use of combinations of vitamins with antioxidant activity could also be associated with a higher risk of developing five types of cancer of the gastrointestinal tract. Or, another study carried out to evaluate the effectiveness of vitamin E in association with selenium in the prevention of prostate cancer highlighted an unexpected increase in the risk of developing this cancer in the group treated with vitamin E after 7-12 years.
What are the categories of people who need to pay particular attention before taking supplements?
Some observational studies, which therefore require further confirmation, suggest that supplements based on antioxidants, iron, vitamin B12 and omega-3 could be associated with an increased risk of breast cancer recurrence. The hypothesis – yet to be confirmed – is that the antioxidant effect of supplements can reduce the effectiveness of some chemotherapy drugs by inhibiting the action of the free radicals they produce. It is therefore important that, especially in cancer patients, the use of vitamin supplements takes place under strict medical supervision.
Are there cases where supplements might be helpful?
Let us remember that the term “supplement” implies that there is a deficiency to be replenished. Therefore, unless there are proven deficiencies, there are no useful supplements capable of counterbalancing the negative effects of an unbalanced diet; furthermore there are no proven health benefits.
When does it make sense to take them?
Taking supplements could make sense as long as these two conditions are met. The first, that is, that the deficiency in question is documented, and the second is that there is a medical prescription. Usually the quantities of elements contained in supplements, such as in the case of vitamins or minerals, are not sufficient in case of significant deficiencies. Let’s take an example. If a person has an iron deficiency and tries to solve it with supplements it is practically useless: in the supplements the iron content is about a tenth of that present in the medicine prescribed in these cases. Paradoxically, one tablet of the drug corresponds to a whole box of supplements. The fact that they can be marketed without a medical prescription depends precisely on their low active ingredient content.
But then why do we find them on the market everywhere and is it so easy to buy them?
For the rules that govern its placing on the market: these provide only that production takes place according to good manufacturing practices, effectively guaranteeing only the correspondence of the composition to what is declared on the label, without the need to demonstrate efficacy and safety through adequate clinical studies. This allows the marketing of a large number of products, which differ in composition and dosages, without information being collected on their usefulness. This is why it would be important to increase awareness both among consumers and doctors themselves.