Nutrients such as vitamin C and zinc could help to ward off common colds and flus in sub-groups of the population, according to a scientific review.
The review found data showing that nutrients such as zinc and vitamin C could provide some benefits for people suffering from a cold (1). Supplementation was only deemed beneficial in population sub-groups such as elderly people, young children and pregnant women.
Vitamin C supplementation taken for prophylaxis reduced the duration of common cold symptoms by eight percent in adults and by 13.6 percent in children, but no effect was found when vitamin C was taken therapeutically. The researchers said that more studies are needed to quantify the effects.
A healthy diet does not prevent a common cold infection, but a sufficient nutrient supply does support the immune system and thus provides the best basis to lower the risk and duration of common cold infections, the researchers commented. While micronutrient deficiencies can impair the immune system, only little evidence exists so far demonstrating a cold-fighting capacity of supplementation.
Experts criticized that the review failed to include studies with high-dose supplements, e.g. vitamin C doses in excess of 2,000 mg a day.