• In this substudy of The Physicians’ Health Study II, a large trial with > 10 years of follow-up in almost 6000 men aged > 65 years, participants randomized to daily multivitamin supplementation reported similar overall cognitive performance, in all categories tested, to those who received placebo.

• Although the results do not support the use of multivitamins for prevention of cognitive decline, an important limitation of this study was that, overall, the enrolled population was well-nourished. Further study in populations at risk for nutritional deficiencies may provide additional information regarding multivitamin use and cognitive function in older adults.

Commentary By

David Rakel MD, FAAFP
Plant Trumps Pill

The Annals of Internal Medicine has published two papers showing that taking a multi-vitamin/mineral (MVI) likely has little, if any, effect on preventing heart disease or cancer1 or cognitive decline. Money would likely be better spent investing in a box of vegetables from your local community farm. There are two significant limitations of a MVI. First, the length of ingredients is inversely proportional to the dose of each one. The company is limited by what they can cram into a capsule, and the longer the list, the lower the dose. Second, the MVI does not honor the synergy of the many nutrients found within the whole plant. Humans take isolated nutrients and randomly put them together in a pill, but nature often combines nutrients in a way that provides much more benefit through eating the plant. Thus, the therapeutic benefit is greater from eating a floret of broccoli than taking a MVI.

These studies are a good example of the importance of primary care and knowing the population we are treating. The patients in this study were well-fed, older physicians who likely did not have significant risk for a deficiency. But others may benefit from specific nutrients. A study of college students in Canada who ate poorly found 1 in 7 to have vitamin C deficiency and early signs of scurvy.2 If you are on long-term acid suppression, you need more vitamin B12.3 And if you are trying to get pregnant, folic acid is a really good idea.

So the evidence is informing us that if someone eats well, a MVI is likely not necessary; but there are those who benefit from specific nutrients. And the best way to use the evidence for ideal outcomes is to have an ongoing trusting relationship that allows the individual’s unique situation to guide what we prescribe.

References

Fortmann SP, Burda BU, Senger CA, et al. Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Evidence Review for the U.S. Preventive Services Task Force [published online ahead of print on November 12, 2013]. Ann Intern Med.doi:10.7326/0003-4819-159-12-201312170-00729.
Cahill L, Corey PN, El-Sohemy A. Vitamin C deficiency in a population of young Canadian adults. Am J Epidemiol. 2009;170(4):464-471.
Lam JR, Schneider JL, Zhao W, Corley DA. Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency. JAMA. 2013;310(22):2435-2442.
ABSTRACT

BACKGROUND

Despite widespread use of multivitamin supplements, their effect on cognitive health—a critical issue with aging—remains inconclusive. To date, there have been no long-term clinical trials to study multivitamin use and cognitive decline in older persons.

OBJECTIVE

To evaluate whether long-term multivitamin supplementation affects cognitive health in later life.

DESIGN

Randomized, double-blind, placebo-controlled trial of a multivitamin from 1997 to 1 June 2011. The cognitive function substudy began in 1998. Up to 4 repeated cognitive assessments by telephone interview were completed over 12 years.

SETTING

The Physicians’ Health Study II.

PATIENTS

5947 male physicians aged 65 years or older.

INTERVENTION

Daily multivitamin or placebo.

MEASUREMENTS

A global composite score averaging 5 tests of global cognition, verbal memory, and category fluency. The secondary end point was a verbal memory score combining 4 tests of verbal memory, which is a strong predictor of Alzheimer disease.

RESULTS

No difference was found in the mean cognitive change over time between the multivitamin and placebo groups or in the mean level of cognition at any of the 4 assessments. Specifically, for the global composite score, the mean difference in cognitive change over follow-up was
0.01 SU (95% CI,
0.04 to 0.02) when treatment was compared with placebo. Similarly, there was no difference in cognitive performance between the treated and placebo groups on the secondary outcome, which was verbal memory (mean difference in cognitive change over follow-up,
0.005 [CI,
0.04 to 0.03]).

LIMITATION

Doses of vitamins may be too low or the population may be too well-nourished to benefit from a multivitamin.

CONCLUSION

In male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits.

Annals of Internal Medicine
Long-Term Multivitamin Supplementation and Cognitive Function in Men: The Physicians’ Health Study II

Ann. Intern. Med 2013 Dec 16;[EPub Ahead of Print], F Grodstein, J O’Brien, JH Kang, R Dushkes, NR Cook, O Okereke, JE Manson, RJ Glynn, JE Buring, JM Gaziano, HD Sesso