A new analysis indicates that most nutritional supplements do not provide any additional protections against cardiovascular disease or cardiovascular death.
The study, published in the Annals of Internal Medicine, looked at data from PudMed, CINAHL, and the Cochrane Library, ClinicalTrials.gov, journal web sites, and reference lists, focusing randomized controlled trials and meta-analyses of randomized controlled trials assessing the effects of nutritional supplements or dietary interventions on outcomes like all-cause mortality, myocardial infarction, stroke, and coronary heart disease.
The analysis included nine systematic reviews and four new randomized clinical trials (277 total trials, 24 interventions, and over 992,000 participants), with a total of 105 meta-analyses generated.
The results suggested moderate-certainty evidence that reduced salt intake decreased the risk for all-cause mortality in patients with normal blood pressure (RR=0.90; 95% CI, 0.85 to 0.95), as well as cardiovascular mortality in patients with hypertension (RR=0.67; 95% CI, 0.46 to 0.99). It also indicated that other nutritional supplements, such as multivitamins, antioxidants, and iron or dietary interventions (reduced fat intake, etc.), did not significantly effect mortality or cardiovascular disease outcomes.
“Reduced salt intake, omega-3 LC-PUFA use, and folate supplementation could reduce risk for some cardiovascular outcomes in adults,” the researchers wrote. “Combined calcium plus vitamin D might increase risk for stroke.”
In an accompanying editorial by Eric J. Topol, MD, of the Scripps Research Translational Institute in La Jolla, CA, the authors illustrated the current state of research in the are of supplements and their effects on outcomes.
“The use of supplements continues to increase in the United States and worldwide, largely without evidence for their efficacy or safety,” they wrote in the editorial. Nearly 3 in 4 persons in the United States use some form of supplements, so it is no wonder that the supplement market is estimated to reach nearly $300 billion in the next 5 yea,” Topol wrote. “In addition to the unbridled uptake, the U.S. Food and Drug Administration lacks regulatory authority over supplements.”
— Annals of Int Med (@AnnalsofIM) July 8, 2019
— Eric Topol (@EricTopol) July 8, 2019
277 trials & 990 000 participants: Reduced salt intake, O-3s & folate reduce risk for some cardiovascular outcomes in adults. Combined Ca + D increase stroke risk 😯 Supplements/Dietary Interventions on CVD Outcomes | American College of Physicians https://t.co/jcXmhjo5eK
— Evan Beloff (@evanbeloff) July 9, 2019
This MA by @safinmc hit a wide range of press from CNN to NYT. Pooling data from 277 trials (24 interventions, 1M pts), the MA found low evidence of positive effect of most dietary supplements & interventions except limiting salt intake in HTN. 🎊 Safi, keep up the great work! https://t.co/xL0bOHgXTj
— Mohamad Alkhouli (@adnanalkhouli) July 9, 2019