A vitamin a day

A daily multivitamin may reduce the chances of getting ill, say US researchers, who find that diabetics could gain significant benefits from a daily vitamin.

The study results, reported in this month's Annals of Internal Medicine​, contradict last year's Oxford study which said taking vitamins was a waste of time.

In a study of just over 100 adults living in North Carolina, people taking a daily multivitamin reported less infection, such as respiratory and urinary tract infections, influenza and gastrointestinal infections, and a lower rate of illness-related absenteeism, than those receiving a placebo. Striking results among those with diabetes had a significant effect on the overall results.

A group of 130 adults aged over 45 years old took a multivitamin and mineral supplement or placebo daily for one year. The multivitamin was said to contain amounts of vitamins and minerals very similar to those found in most commercially available multivitamin and mineral supplements.

The researchers report that more participants receiving placebo reported an infectious illness over the study year than did participants receiving multivitamin and mineral supplements (73 per cent versus 43 per cent of those receiving vitamins). Infection-related absenteeism was also higher (57 per cent) in the placebo group than in the treatment group (21 per cent).

The group included 51 participants with type 2 diabetes. Among those receiving placebo, 93 per cent reported an infection compared with 17 per cent of those receiving supplements.

They said that the results on diabetes patients were likely due to the correction of micronutrient deficiencies. "It remains uncertain, however, whether these small differences in nutritional status were enough to account for the dramatic difference in outcome. This uncertainty is due not only to the limitations of our study but also to inherent difficulties in defining micronutrient deficiency,"​wrote the study authors.

The team added that a larger clinical trial is needed to determine whether these findings can be replicated not only in diabetic people but also in any nutritionally deficient population. They suggest that multivitamins may have most benefit for populations in the developing world.