The dietary supplements


Dietary supplements are becoming more and more popular year after year. The enthusiasm they create come from the benefits they may provide in a more or less natural way. The world of sports is not spared by this enthusiasm, however, supplements should not be taken lightly.

Definition of dietary supplements

The official definition (article 2 of Decree 2006-352) explains that a dietary supplement is a foodstuff that is a concentrated source of nutrients or other substances with a nutritional or physiological effect. The ingredients that make up dietary supplements are therefore strictly regulated.

Composition of the dietary supplements


Vitamins cannot be synthesized by the human body, except for vitamin D. They are therefore essential and should be provided by the diet, combined with dietary supplements in the event of deficiencies. They include vitamins of the B group involved in the metabolic function, vitamin C for vitality and natural defences, vitamin A for eye health, vitamin D for bone health and vitamin E for its antioxidant properties...

Minerals and trace elements

Minerals are our allies for a healthy body. They are involved in growth, biological functions, the regulation of our metabolism, etc.

Minerals are provided by standard diet and can also be consumed as dietary supplements for a more targeted action in the event of a deficiency.

Substance with an ergogenic effect

Substance that may help increase the performances or the training capacity. The most commonly used ones include: caffeine, cola, ginseng, taurine, quinine and plant extracts, etc.

Plant extracts and plant-derived products

Plants and plant-based preparations are among the most common ingredients in dietary supplements. These ingredients are made or derived from plants. Plants or plant-based preparations with pharmacological properties and intended exclusively for therapeutic use are outside this scope.

Amino acids and proteins

Substance with a "fat burning" effect

caffeine, carnitin, coenzyme Q10, Guarana, Ephedra and their extracts or derived products...

Substance with an effect on muscle mass and strength development

Creatine, Prohormone or not, etc.

Note that you should pay attention to the purity of the product (e.g.: creatine that is improperly purified when processed) and the presence, intended or not, of forbidden substances (cross-contamination or added anabolic substances, etc.). Generally speaking, products should be purchased from a store in the United Kingdom, or optionally from the website of a company duly identified as reliable. Remember that dietary supplements, unlike drugs, require no approval prior to marketing. The product compliance, safety and non-misleading of consumers are essentially the responsability of the manufacturers. Therefore, the fact that it is sold in a pharmacy does not guarantee the efficiency or safety of a dietary supplement.

Difference between dietary supplements and complementary food supplements

These terms may be used similarly, but they should be distinguished:

  • Dietary supplements refer to foodstuffs eaten in addition to standard diet and providing a concentrated source of nutrients or other substances with a nutritional or physiological effect. The objective is to reach the recommended dietary intakes.
  • Complementary food supplements refer to concentrated nutrients or other substances used while the dietary intakes are already covered by the standard diet, with a view to exceeding them. It can be assimilated as a dose above your needs, without providing any benefit.

When to take a dietary supplement?

The use of dietary supplements should be targeted based on a specific nutritional deficiency  evidenced by clinical signs, a nutritional evaluation and possibly a test of the blood levels of this element.

The use of dietary supplements should come in addition to standard foods, as part of a balanced diet. The occurrence of a nutrient deficiency should first lead to adjusting or rebalancing the diet to address the deficiency before using supplements.

Therefore, supplements are indicated when the standard diet can no longer cover the specific needs due to physical activity. It may occur in cases of energy restrictions, or when the intake of trace elements becomes insufficient despite the consumption of foods with a high vitamin and mineral density. Conversely, certain physical activities with high energy expenditure require intakes of nutrients and trace elements that may be difficult to cater for. In certain situations of food unavailability, athletes may not find the food they need to meet their dietary balance and nutritional needs (autonomous multiday races, trail running, competitions abroad, etc.

Are dietary supplements unsafe?

Using dietary supplements is not insignificant. They all have an effective dose and an upper limit at which a potential risk of harmful effects is observed. Any supplement may pose a risk and should be used at the approved dosage.

Let's take the example of the highly trivialized vitamin C - it is often over-consumed. Its invigorating properties lead many athletes to over-consume it, hoping for a positive effect on their performances or recovery. It is nothing of the sort since excessive use of vitamin C alters the antioxidant defences and therefore reduces the recovery capacity.

Doping or not doping?

The use of dietary supplements is sometimes viewed as doping. First, we need to define what doping is. A very simple definition of doping is as follows: "Doping is the use by sporting competitors of forbidden substances or processes appearing on a list drawn up annually by the World Anti-Doping Agency, in order to improve their performances.

Dietary supplements are not part of this list of forbidden products, they are not doping. However, they are used with a view to improve performances, so this can be referred to as a doping behaviour that may unlock the door to other substances. You should therefore always be alert as to why you use dietary supplements. 

Marie Fauchille
Dietician | Nutritionist
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      Vitamins are micronutrients that are essential to proper body function. They are involved at low concentrations in many vital processes. Provided by food, they fall into two categories:
      - Fat soluble vitamins: Vitamins A, D, E and K
      - Water-soluble vitamins: Vitamins B and C


      Minerals are essential to the body. Mineral intake is a factor of good health. A balanced diet usually cater for the athlete's needs, however, certain adjustments may be necessary in specific circumstances, such as intensive sports, specific conditions, or insufficient sunlight...