In short:
- There are 13 essential vitamins and around fifteen minerals and trace elements: all are essential, in small amounts.
- European labels refer to nutrient reference values (NRVs), for example 375 mg for magnesium, 5 µg for vitamin D and 2.5 µg for vitamin B12.
- The most commonly insufficient intakes concern vitamin D in winter, vitamin B12 for vegans and iron for women of childbearing age.
- More is not better: EFSA sets tolerable upper intake levels, and combining several supplements is a common cause of overdose.
When you do sport several times a week, you inevitably end up wondering about vitamins and minerals. Is your diet enough? Should you take magnesium, vitamin D, a multivitamin? Clear answers are found in official references rather than on packaging. Here are the essentials, nutrient by nutrient.
The role of the main vitamins and minerals
To describe the role of each nutrient, this article sticks to the authorised claims in the EU register1. It is less spectacular than the promises on packs, but it is what has been validated.
| Nutrient | Examples of authorised claims | Good food sources |
|---|---|---|
| Vitamin D | Contributes to the normal function of the immune system and to the maintenance of normal bones | Oily fish, eggs, sun exposure |
| Vitamin B12 | Contributes to a reduction of tiredness and to normal red blood cell formation | Animal products only |
| Vitamin C | Contributes to normal collagen formation and to the normal function of the immune system | Citrus fruit, kiwi, peppers, cabbage |
| Magnesium | Contributes to a reduction of tiredness and to normal muscle function | Nuts, pulses, whole grains, dark chocolate |
| Iron | Contributes to normal oxygen transport in the body | Meat, pulses, spinach |
| Zinc | Contributes to the normal function of the immune system and to the maintenance of normal skin | Seafood, meat, seeds |
| Iodine | Contributes to the normal production of thyroid hormones | Fish, seafood, iodised salt |
To find the exact content of a food, use the ANSES Ciqual table2, the reference food composition database in France.
Vitamins and minerals: what exactly are we talking about?
Vitamins and minerals are micronutrients: the body needs them in small amounts (milligrams, sometimes micrograms), but it cannot make all of them. They must therefore come from food.
- Vitamins number 13. There are fat-soluble vitamins (A, D, E, K), stored in the body’s fat, and water-soluble vitamins (C and the eight B vitamins), which are stored little, with the notable exception of vitamin B12.
- Minerals include macrominerals, needed in larger amounts (calcium, magnesium, phosphorus, potassium), and trace elements, needed in tiny amounts (iron, zinc, iodine, selenium, copper).
The World Health Organization3 points out that micronutrient deficiencies remain a public health issue, including in countries where food is plentiful but not very varied.
How much do you need? Official reference values
Two types of references coexist, which is often a source of confusion.
Nutrient reference values (NRVs)
These are the values used on labels, set by Regulation (EU) No 1169/20114. When a label says “100% NRV”, it refers to these values. They are the same for everyone and serve as a common benchmark.
| Nutrient | NRV per day |
|---|---|
| Vitamin D | 5 µg |
| Vitamin B12 | 2.5 µg |
| Vitamin C | 80 mg |
| Magnesium | 375 mg |
| Iron | 14 mg |
| Zinc | 10 mg |
Individual nutritional references
ANSES5 and EFSA6 publish more detailed references by age, sex and situation (pregnancy, breastfeeding). They can differ significantly from NRVs. A telling example: the NRV for vitamin D is 5 µg, whereas the adequate intake set by ANSES for an adult is 15 µg a day when skin synthesis is minimal.
Who risks a shortfall in vitamins and minerals?
A varied diet covers most needs. Some profiles, however, deserve more attention:
- Many people in winter for vitamin D, because the skin makes little of it when sunlight drops. ANSES details how to ensure an adequate intake7.
- Vegans for vitamin B12, which is only found in animal products.
- Women of childbearing age for iron, because of menstrual losses.
- Endurance athletes, whose high energy needs and sweating make diet even more important. The guide to sports nutrition supplements covers the topic.
- Older people, whose appetite and absorption of some nutrients decrease.
Before buying anything, look at your plate. The article on micronutrition and diet explains how.
When a vitamin or mineral supplement makes sense
The right approach: target rather than pile up. A supplement makes sense when a specific intake is hard to cover, and it is ideally discussed with a health professional.
| Situation | Nutrient concerned | Good habit |
|---|---|---|
| Winter, little sun exposure | Vitamin D | Talk to your doctor, especially before any high dose |
| Vegan diet | Vitamin B12 | Essential supplement, dose on medical advice |
| Tiredness, stress, intense sport | Magnesium | Look at dietary intake first, choose a well-tolerated form |
| Heavy periods, tiredness | Iron | Never without a blood test: excess iron is not harmless |
| Little variety in the diet | Multivitamin | Occasional help, with a close look at the dose of each nutrient |
For magnesium, probably the best-selling mineral supplement, the full magnesium fact sheet details needs, forms, dosage and precautions.
The risks of overdose
More is not better. EFSA has set tolerable upper intake levels, meaning daily intakes not to be exceeded over the long term. A few examples for an adult:
- Vitamin D: 100 µg a day.
- Zinc: 25 mg a day.
- Magnesium from supplements: 250 mg a day, above which digestive problems may occur.
The most common trap is combination: a multivitamin, an “immunity” supplement and an enriched magnesium can provide the same nutrient three times over. ANSES also regularly warns of the risk of vitamin D overdose in infants when several products are given at the same time.
How to choose a vitamin or mineral supplement
- The form: it should be clearly stated (for example cholecalciferol for vitamin D3, bisglycinate or citrate for magnesium).
- The elemental dose: for minerals, look at the amount of elemental magnesium, zinc or iron per dose, not the weight of the salt.
- The % NRV: it lets you compare two products quickly.
- The excipients: prefer a short list, with no unnecessary colouring or sweetener.
To compare the manufacturers themselves, read the ranking of the best food supplement brands and the guide on how to choose a supplement brand.
Frequently asked questions
Which vitamins and minerals matter most?
They all have a role, and none replaces another. Thirteen vitamins are recognised as essential (A, C, D, E, K and the eight B vitamins), along with around fifteen minerals and trace elements, including calcium, magnesium, iron, zinc, iodine and selenium. Those most often discussed as supplements are vitamin D, magnesium, vitamin B12, iron and zinc.
How can you tell if you lack vitamins or minerals?
The signs are often non-specific, such as tiredness. Only a health professional can confirm a shortfall, sometimes with a blood test. Analysing your diet over a few days also gives a good indication of insufficient intakes.
Can you take too many vitamins and minerals?
Yes. EFSA has set tolerable upper intake levels for several nutrients, for example 100 µg a day of vitamin D, 25 mg a day of zinc or 250 mg a day of magnesium from supplements for adults. The risk mainly comes from combining several products.
Should you take a multivitamin every day?
Not necessarily. A varied diet covers most needs. A multivitamin can help out when the diet is restricted, but it is better to target the nutrient that is really lacking than to pile up intakes at random.
Sources
European Commission, EU Register of nutrition and health claims made on foods ↑
EUR-Lex, Regulation (EU) No 1169/2011 on the provision of food information to consumers ↑
ANSES, « Les références nutritionnelles en vitamines et minéraux » (in French) ↑
ANSES, « Vitamine D : pourquoi et comment assurer un apport suffisant ? » (in French) ↑