Iron
The mineral responsible for oxygen transport. A deficiency in this mineral is the most common in the world, but too much is toxic: this is a supplement that should not be taken indiscriminately.
Benefits
- Reduces fatigue in women who are not anaemic but have nutritional deficiencies: a clear effect is seen after just one month, compared with a placebo
- Improves attention and concentration, including in people who are not anaemic (meta-analysis in children and adults)
- Prevents anaemia and nutritional deficiency during pregnancy (a review involving 43,274 women)
- In children with developmental delays, it helps to catch up on delays in motor and language development
Precautions
Do not take supplements without having a blood test: the body has no way of eliminating excess iron, which accumulates in the liver. Digestive problems and black stools are very common. Avoid tea, coffee and calcium, as these reduce absorption. It is also worth noting that, in pregnant women who are neither anaemic nor iron-deficient, routine iron supplementation offers no proven benefit, and excessively high haemoglobin levels are associated with the same risks as excessively low levels.
Recommended dosage
14 mg per day meets the reference intakes. Corrective doses (30 to 100 mg) should be taken on medical advice, following a blood test — and are sometimes taken every other day, which improves absorption.
What the studies say
Cette étude a examiné les effets d'une supplémentation en fer chez des adolescentes présentant une carence en fer non anémique. Après 8 semaines de traitement oral au sulfate ferreux, les mesures hématologiques du statut en fer se sont significativement améliorées. Les filles ayant reçu le fer ont également montré de meilleures performances à un test d'apprentissage verbal et de mémoire.
Bruner AB, Joffe A, Duggan AK, Casella JF, Brandt J. — Lancet (London, England) (1996) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more