MDNews - South Central Pennsylvania

Supplements are appropriate for certain individuals with diagnosed nutritional deficiencies, experts say, but a growing body of evidence advises against routine use for the purpose of improving cardio- vascular or overall health. In a 2018 study, for example, David Jenkins, MD, PhD, DSc, Professor in the Departments of Nutritional Sciences and Medicine at the University of Toronto and St. Michael's Hospita l, and colleagues conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) of supplement effects on cardiovascular disease outcomes and all-cause mortality, and they found no consistent benefits for multivitamins, vitamin D, calcium and vitamin C supplements. "I don't think anyone's come to the con- clusion that supplements are the answer to good health," Dr. Jenkins says. "I think that's been the prevailing view for a very long time." A DEARTH OF BENEFITS Dr. Michos was part of a team of research- ers that conducted a systematic review of meta-analyses of RCTs published through March 2019 to assess the certainty of evidence regarding the efficacy of various supplements and dietary interventions for prevention of cardiovascular disease. In analysis that included 277 RCTs involving nearly 1 million participants, the team evaluated 16 common supplements and eight dietary interventions. The findings appear in Annals of Internal Medicine. Most supplements and diets neither reduced nor increased risk of mortality or cardiovascular disease, but a small number conferred benefits. Omega-3 fatty acid (fish oil) supplements reduced heart attack risk by 8% and coronary artery disease risk by 7%. People with normal blood pressure who followed a low-salt diet saw a 10% reduction in mortality, and people with hypertension who adhered to the same diet reduced their risk of heart disease-related death by 33%. Individuals who used folic acid supplements reduced their stroke risk by 20%. Most of that data, however, came from China, where food is not fortified with folic acid as it is in the United States. That calls into question whether Americans would enjoy similar risk reduction from additional folic acid. Lead author Safi Khan, MD, Assistant Professor of Medicine at West Virginia University, was slightly surprised by the lack of heart-hea lth benefits from the Mediterranean diet, given the positive effects demonstrated in other studies. Dr. Khan cautions, however, that trials of the Mediterranean diet are few, and Dr. Michos points out that it is notoriously difficult to study dietary interventions in randomized trials. "I really believe that if we [were to] have more data on the Mediterranean diet … there is a possibility that it might show some effect, but at this point in time, the totality of evidence suggests the Mediterranean diet is not effective," Dr. Khan says. EMPHASIZE PROVEN INTERVENTIONS, EXPERTS SAY Amitabh Pandey, MD, staff cardiologist in the Division of Cardiology at Scripps Clinic and Clinical Scholar at the Scripps Resea rch Tra nslationa l Institute in La Jolla, California, says the study adds to evidence that supplements, on the whole, do not live up to consumer hopes. "More often than not, studies investi- gating supplements fail to show benefits, such that we once again are shown that there is no strong evidence for supple- ments in cardiovascular outcomes," says Dr. Pandey, who was not involved in the research. "The authors of this study do a good job in showing the level of evidence for supplements, with most being uncer- tain or, at best, low certainty. We need to do better for our patients." For Dr. K ha n , t hat mea ns test i n g patients for nutritiona l def iciencies i f su spicion s ex i s t a nd prescr ibi n g supplement at ion or repla cement a s appropriate, such a s vita min B12 for individua ls with pernicious a nemia . Dr. Khan and colleag ues would like to perform subgroup analyses of the RCTs in the study and determine the degree of heterogeneity of the effects observed in RCTs versus observationa l studies, but the difficulty of obtaining individua l- level data ma kes those tasks difficult, and they are not actively pursuing those lines of inquiry. Drs. Khan and Michos encourage physicians to have a frank dis- cussion with patients about nutritiona l supplements and dietary interventions, and to continue to recommend the pillars of hea r t disease prevention: physica l activity, a hea lthy diet, smoking cessa- tion, stress management and compliance with treatment. n Proceed Cautiously With Calcium Supplements IN A RECENT meta-analysis, researchers found that when taken together, calcium and vitamin D supplements increased stroke risk 17%, possibly because elevated blood calcium levels may lead to increased thrombosis, according to Erin Michos, MD, MHS, FACC, FAHA, Associate Professor of Medicine and Epidemiology and Associate Director of Preventive Cardiology at the Ciccarone Center for the Prevention of Heart Disease, Division of Cardiology, Johns Hopkins Medicine, who was part of the research team. That finding — along with others going back more than a decade showing calcium supplements can have negative effects on heart health — gives her cause for concern. "I recommend patients get their recommended daily allowances [RDAs] of calcium from food sources as much as pos- sible, not supplements," Dr. Michos says. "If one is truly unable to meet RDA of calcium from food, then I suggest using the smallest effective supplemental doses … in populations at risk for osteoporosis, [but] only after dietary modifications have been exhausted." M D N E W S . C O M /// M D N E W S S O U T H C E N T R A L P E N N S Y LVA N I A ■ 2 0 2 0 ❰❰❰❰❰ 1 3

• Cover