No Need for Supplements?

Summarized by Robert W. Griffith, MD
October 11, 2005 (Reviewed: October 17, 2005)

Introduction

Although one in four older people in the United Kingdom take nutritional supplements, there's still doubt as to whether they have obvious benefits on the heath of those taking them. In particular, do they prevent infectious conditions? A study conducted in Scotland has explored this question, and reported the findings in the British Medical Journal. Here's a summary.

What was done

Participants over 65 from 6 general practices in Grampian, Scotland, were enrolled. They were only excluded if they had been taking nutritional supplements during the previous three months.

The participants were assigned randomly to take one tablet daily of a multivitamin and multimineral supplement, or a matched placebo (dummy) tablet, for one year.

They were asked to complete daily diaries on infections and any contact with their primary care physician they may have had.

To measure the possible benefits of supplements, the focus was placed on the number of contacts with primary care doctors for infections, the number of days infection lasted, and a 'quality of life' scale. In addition, antibiotic prescriptions, hospital admissions, and reported side effects were evaluated.

What was found

Of the 910 people recruited into the study, only 13% were lost to follow-up during the next year. The average age of participants was 72. The baseline nutrition questionnaire showed that over a quarter of them were at high risk of nutritional deficiency for iron, folate, vitamin C, or vitamin D.

There was no difference in the number of doctor contacts for infection between the group taking supplements and the placebo group. The numbers of days of self-reported infection were the same for both groups, as were the numbers of upper respiratory tract infections (coughs and colds). And 'quality-of-life' scores were unaffected by the supplements.

None of the other measures made showed any significant differences between the supplements and the placebo groups.

What this study shows

The findings indicate that older people (at least in Scotland) don't need to take vitamin or mineral supplements to avoid infections. Some caveats, however: there were few people over 85 in the study; nursing home patients weren't included; and the results were based largely on self-reporting. Moreover, t he possible benefits of one particular supplement might have been buried among the ineffectiveness of the others. Nevertheless, the study demonstrates clearly enough that some of the money spent on supplements might as well be spent on better (i.e. more nutritious) food.

Source

• Effect of multivitamin and mineral supplements on morbidity from infectious in older people (MAVIS trial): pragmatic, randomized, double blind, placebo controlled trial. A. Avenell, MK. Campbell, JA. Cook,  et al. , BMJ, 2005, vol. 331, pp. 323--327

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