Dietary supplements: useful or just winter gimmicks?

The weather is getting colder, fatigue is setting in, and pharmacy shelves are filling up with capsules promising energy and immunity. Vitamin C, magnesium, vitamin D… Nearly two out of three French people take dietary supplements . But is it really necessary to take them as winter approaches?

In most cases, our diet already covers our vitamin and mineral needs. Supplements only become necessary in cases of proven deficiency, prolonged fatigue, or an unbalanced diet. In other words: if you eat a varied diet and sleep well, most "energy" pills are... unnecessary. Except perhaps for one: vitamin D.

Between November and March, the lack of sunlight limits the body's natural production of vitamin D. This vitamin plays a key role in:

• immunity,
• the mineralization of the skeleton,
• and calcium absorption.

The elderly, children, and those who rarely go outside are particularly affected. For example, one tablespoon of cod liver oil provides approximately 1,000 IU of vitamin D per day.

We often hear that vitamin C “gives you energy.” In reality, this is false: it doesn’t “give” you anything. It simply contributes to the proper functioning of the immune system and helps reduce fatigue… only if you are deficient in it.

Deficiencies are rare: a kiwi, an orange, or a raw bell pepper is enough to reach the recommended 100 mg per day. Studies also show that vitamin C does not prevent colds in the general population. However, in athletes or people under high stress, it could reduce the incidence by about 50% and slightly shorten the duration of symptoms (about 8% in adults). But there is no official recommendation to take it routinely.

Does that mean we should stop everything? Not necessarily. Vitamins and minerals are essential, but supplements can never replace a healthy lifestyle. The best strategy remains the simplest:

• Eat a varied diet.
• Get enough sleep.
• Stay well hydrated.
• And, in case of a cold, opt for old-fashioned remedies: hot drinks, rest and nasal irrigation.