Korean researchers conducted a meta-analysis of 50 trials that reported the efficacy of vitamin or antioxidant supplements for the prevention of cardiovascular disease, and investigated for an association between vitamin or antioxidant supplementation and major cardiovascular events. A total of 294,478 participants were included.
Use of vitamin or antioxidant supplements was not associated with a reduced risk of major cardiovascular events, showing a relative risk of 1.00, compared with those not taking the supplements. Sub-group analysis of each supplement featured in the study found low dose vitamin B6 significantly reduced risk of cardiovascular events by 8%, while high dose vitamin A significantly increased the risk by 41%, compared to individuals not taking supplements.
What does it mean for GPs?
Despite the positive results for some vitamins, the authors concluded that there is ‘no evidence to support the use of vitamin or antioxidant supplements for the primary or secondary prevention of major cardiovascular events.’ They added that governments and food agencies should strictly evaluate the efficacy and safety of vitamins and antioxidants before marketing.
Dr Ivan Benett, GPSI in cardiology, Manchester: ‘I believe the question is too broad to have been useful or convincingly answered. A narrower question would be more relevant, such as “does vitamin D supplementation in deficient people reduce the risk of ischaemic heart disease?” I don’t believe any conclusions can be drawn from the meta-analysis other than to wait for definitive trial evidence before prescribing potentially expensive and possibly harmful drugs.’