A healthy diet that includes foods rich in antioxidants and vitamins has consistently been associated with lower risk of atherosclerosis.  Whether secondary risk reduction can be achieved with oral vitamin supplementation is unclear.  The TACT (Trial to Assess Chelation Therapy) study was a 2×2 factorial design randomized trial to assess the impact of chelation therapy or multivitamin supplementation on cardiovascular outcomes among patients with a history of cardiovascular disease.  This study reports the outcomes of the multivitamin supplementation compared with placebo.  The primary endpoint was composite of death from any cause, reinfarction, stroke, coronary revascularization, or hospitalization for angina.  The pre-specified secondary endpoint was the composite of cardiovascular death, reinfarction, or stroke.  Patients were intended to take high dose oral multivitamins or placebo for 5 years, however the study suffered from significant drop out in both arms.  Of the 1708 patients randomized, only about 800 received the assigned treatment for more than 3 years.  The outcomes were assessed using intention-to-treat analysis, and showed no significant differences between groups for the primary or secondary end points. 

Conclusions

While the results of this study must be interpreted with caution due to the high drop-out rate and any signal of benefit (or harm) could be obscured. However, this study agrees with the growing literature that suggests no benefit of vitamin supplementation for secondary cardiovascular risk reduction.

 Summarized by Steven M. Bradley and Preston M. Schneider

• Lamas GA, Boineau R, Goertz C, et al. Oral High-Dose Multivitamins and Minerals After Myocardial Infarction: A Randomized Trial. Annals of Internal Medicine. 2013;159(12):797–805. doi:10.7326/0003-4819-159-12-201312170-00004.