Vitamin C
An antioxidant that the human body cannot produce itself, which plays a role in immunity, fatigue and iron absorption.
Benefits
- Halves the incidence of respiratory infections following very prolonged exertion: 33 per cent of ultra-marathon runners taking the supplement, compared with 68 per cent on a placebo
- Lowers blood uric acid levels, a marker associated with gout (13 trials, 556 participants)
- Reduces muscle soreness within 24 hours of a very strenuous session, when taken in high doses
- Reduces the duration of respiratory infections in elderly hospital patients
Precautions
At high doses (more than 1,000 mg per day): digestive problems, and an increased risk of kidney stones in people who are predisposed to them. May interfere with certain capillary blood glucose tests. It is also worth noting that most Westerners already have sufficient vitamin C in their diet, and trials show no benefit for them — the benefits are mainly seen in people with a genuine deficiency, smokers and those engaged in extreme endurance activities.
Recommended dosage
80 to 200 mg a day, with a meal. Any amount in excess of approximately 1,000 mg is simply excreted in the urine.
What the studies say
Cette méta-analyse d'essais contrôlés randomisés a examiné l'effet de la supplémentation en vitamine C sur la tension artérielle. Les résultats ont montré qu'une supplémentation en vitamine C réduisait la tension artérielle systolique et diastolique dans les essais à court terme. Les réductions étaient plus prononcées chez les participants hypertendus. Des études à long terme sont nécessaires pour confirmer ces effets et évaluer les événements cliniques.
Juraschek SP, Guallar E, Appel LJ, Miller ER. — The American journal of clinical nutrition (2012) — 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