Multivitamins may reduce heart attack risk in women

Long-term use of multivitamin supplements may be linked to a reduced risk of myocardial infarction in women, according to a new Swedish study.

In the observational population-based study, 31,671 women with no history of cardiovascular disease (CVD) and 2,262 women with a history of CVD aged 49–83 years completed a self-administered questionnaire regarding dietary supplement use, diet, and lifestyle factors (1). The multivitamin supplements were estimated to contain vitamin A (0.9 mg), vitamin C (60 mg), vitamin D (5 mcg), vitamin E (9 mg), vitamin B1 (1.2 mg), vitamin B2 (1.4 mg), vitamin B6 (1.8 mg), vitamin B9 (400mcg) and vitamin B12 (3 mcg). During an average of 10.2 years in the CVD-free group, regularly use of multivitamins only, compared with no use of supplements, was associated with a reduced risk of myocardial infarction (MI). In the CVD group, use of multivitamins alone or together with other supplements was not associated with MI.

The researchers suggest the potentially protective effects of multivitamins on myocardial infarctions may be due to antioxidant vitamins such as vitamin C, vitamin E, B vitamins and minerals included, which may be involved in reducing the atherosclerotic process by scavenging free radicals. Further studies would be needed to confirm or refute the findings and, if confirmed, to clarify what composition of multivitamins (doses and ingredients included) and duration of use is needed to observe beneficial effects on MI.

The study results agree with some observational studies, which linked multivitamin supplement use with an up to a 51% lower risk of MI in women and/or men (2–6), but not with others (7, 8). Experts commented that the reason for this apparent contradiction may be that the dose and the composition of ingredients vary in multivitamin supplements used in different studies. Most randomized controlled trials (RCTs) have failed to observe any benefit from vitamin supplements on cardiovascular health. Possible reasons may be that many RCTs were performed among participants with existing CVD, whereas observational studies are based mainly on healthy participants, indicating the potential of long-term supplement intake in preventing (rather than treating) CVD. Furthermore, the contradiction among studies may also be explained by the shorter follow-up in the majority of RCTs than in many observational studies.

1. Rautiainen S. et al. Multivitamin use and the risk of myocardial infarction: a population-based cohort of Swedish women. Am J Clin Nutr. 2010; 92(5):1251–1256.
2. Holmquist C. et al. Multivitamin supplements are inversely associated with risk of myocardial infarction in men and women. J Nutr. 2003; 133:2650–2654.
3. Klipstein-Grobusch K. et al. Dietary antioxidants and risk of myocardial infarction in the elderly: the Rotterdam Study. Am J Clin Nutr. 1999; 69:261–266.
4. Rimm E. B. et al. Folate and vitamin B6 from diet and supplements in relation to risk of coronary heart disease among women. JAMA. 1998; 279:359–364.
5. Watkins M. L. et al. Multivitamin use and mortality in a large prospective study. Am J Epidemiol. 2000; 152:149–162.
6. Pocobelli G. et al. Use of supplements of multivitamins, vitamin C, and vitamin E in relation to mortality. Am J Epidemiol. 2009; 170:472–483.
7. Neuhouser M. L. et al. Multivitamin use and risk of cancer and cardiovascular disease in the Women’s Health Initiative cohorts. Arch Intern Med. 2009; 169:294–304.
8. Muntwyler J. et al. Vitamin supplement use in a low-risk population of US male physicians and subsequent cardiovascular mortality. Arch Intern Med. 2002; 162:1472–1476.