Vitamin supplementation and cardiovascular disease

Abstract

• Objective: To review the evidence of the effectiveness of antioxidant vitamins for the prevention and treatment of cardiovascular disease (CVD). • Methods: Qualitative assessment of the literature. • Results: Data do not support the hypothesized cardioprotective effect of supplemental vitamin A, and there is a suggestion of toxicity with higher doses. Interventional studies with β-carotene fail to support any benefit on CVD and many suggest harm from β-carotene supplementation. Observational studies of vitamin C supplementation have yielded variable results. Small interventional studies with surrogate endpoints and large prospective interventions overall have not shown a benefit of vitamin E on preventing CVD. Meta-analyses of these large studies corroborate the lack of effect of vitamin E. A benefit of folate on CVD risk has been demonstrated, but recent fortification of grains in the United States with folate might limit the translation of these study results into current practice. Nicotinic acid decreases the risk of CVD through its effect on lipids, but side effects limit its use. The majority of vitamin combination studies suggest no benefit, and several notable vitamin combination studies raise the concern that some combinations may cause harm. Perhaps the strongest beneficial effect with multivitamins is seen in those with or at risk for baseline vitamin deficiencies. • Conclusion: Data from this review do not support the use of vitamins for primary or secondary prevention of CVD. Indeed, there is even the suggestion of possible harm in some groups. Thus, careful consideration is needed prior to prescribing or condoning supplemental vitamin use for the prevention or treatment of CVD.