Do Dietary Supplements, Interventions Actually Improve CVD Outcomes?

Many nutritional supplements and dietary interventions appear to have little or no effect on mortality or cardiovascular disease outcomes, according to the results of a recent study.

To explore the effects of supplementation and dietary interventions on these outcomes in adults, the researchers conducted an analysis of data from 277 randomized controlled trials of 24 dietary supplements and interventions including 992,129 participants.

Overall, the researchers found that:

• Reduced salt intake was associated with decreased risk for all-cause mortality in normotensive participants (risk ratio [RR] 0.90) and cardiovascular mortality in hypertensive participants (RR 0.67; Moderate-certainty evidence).
• Omega-3 long-chain polyunsaturated fatty acid was associated with reduced risk for myocardial infarction (RR 0.92) and coronary heart disease (RR 0.93; Low-certainty evidence).
• Folic acid was associated with lower risk for stroke (RR 0.80; low-certainty evidence).
• Calcium plus vitamin D was associated with increased risk for stroke (RR 1.17; moderate-certainty evidence).
• Other supplements, including vitamin B6, vitamin A, multivitamins, antioxidants, and iron and dietary interventions, such as reduced fat intake, had no significant effect on mortality or cardiovascular disease outcomes (very low– to moderate-certainty evidence).

—Michael Potts

Reference:

Khan SU, Khan MU, Riaz H, et al. Effects of nutritional supplements and dietary interventions on cardiovascular outcomes: an umbrella review and evidence map [published online July 9, 2019]. Ann Intern Med. DOI: 10.7326/M19-0341