Doctors often recommend certain dietary interventions — such as following a Mediterranean-type diet or cutting salt intake — in the interest of protecting heart health. On top of this, many individuals believe that dietary supplements will help them stay healthy. Can supplements and dietary interventions protect the heart? Not according to a new meta-analysis.
Common knowledge has it that diet and lifestyle play an important role in supporting a person’s physical health and overall well-being. That is why doctors may advise their patients to modify their diets and lifestyle habits by making them more conducive to good health.
In particular, dietary interventions can allegedly help individuals safeguard their cardiovascular health, preventing heart disease and events such as strokes. Dietary guidelines for people in the United States advise that people adhere to healthful diets, such as a vegetarian diet or the Mediterranean diet, which is rich in vegetables, legumes, and lean meat.
On a related note, many individuals believe that taking dietary supplements can enhance different aspects of their health, including heart health, although recent studies have contradicted this assumption.
Now, a meta-analysis by researchers from different collaborating institutions — including The Johns Hopkins School of Medicine in Baltimore, MD, West Virginia University in Morgantown, and Mayo Clinic in Rochester, MN — suggests that many interventions and even more supplements may have no protective effect for the heart, and some may even harm cardiovascular health. The review — the first author of which is Dr. Safi Khan from West Virginia University — appears in Annals of Internal Medicine.
In their research, Dr. Khan and team analyzed the data from 277 randomized controlled trials that had involved almost 1 million participants between them. They looked at the effects of 16 nutritional supplements and eight dietary interventions on cardiovascular health and mortality. The supplements that they took into consideration were: selenium, multivitamins, iron, folic acid, calcium, calcium plus vitamin D, beta carotene, antioxidants, omega-3 long-chain polyunsaturated fatty acids, and vitamins A, B complex, B-3, B-6, C, D, and E.
The dietary interventions included: modified dietary fat, reduced salt (in people with normal and high blood pressure), reduced saturated fat, Mediterranean diet, reduced dietary fat, higher intake of omega-6 polyunsaturated fatty acids, and higher intake of omega-3 alpha-linolenic acid.
Dr. Khan and colleagues did find that some of these interventions had a positive effect. For instance, eating less salt may reduce the risk of premature death in people with a normal blood pressure, although only with moderate certainty. Moreover, they concluded that omega-3 long-chain polyunsaturated fatty acids protected against heart attacks and coronary heart disease and that there was an association between folic acid intake.
