Umbrella review of the efficacy of nutritional supplements and dietary interventions
A fascinating new systematic review of meta-analyses and trials assessing the efficacy of nutritional supplements has shown some interesting results.
The study, by Khan and colleagues, was recently published in the Annals of Internal Medicine. It is a systematic review of existing meta-analyses of randomised controlled trials (RCTs) and RCTs that assessed the efficacy of nutritional interventions on all-cause mortality or cardiovascular outcomes.
Nine systematic reviews and four new RCTs which incorporated 992 129 participants were found to be eligible for this study for a total of 105 meta-analyses of 24 interventions. An evidence map was created for the efficacy of supplements for prevention of cardiovascular disease.
The only supplements or interventions that were found to reduce risk of cardiovascular disease were reduced salt intake, omega-3 fatty acids and folate. Calcium plus vitamin D demonstrated an increased risk of stroke. No other supplements or dietary modifications showed improved survival or cardiovascular benefits. In general, the quality of evidence was low.
See the report on the Annals website.