A new study warns that most dietary supplements do nothing to protect against cardiovascular diseases, including heart disease, stroke, and even heart attacks. Based on the research, the team of researchers from West Virginia University concluded that most nutritional supplements do not offer protection against potentially fatal heart conditions.
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The study, which was published in the journal Annals of Internal Medicine, shows that although reduced salt intake and certain supplements may lower the risk of cardiovascular diseases, most nutritional supplements do not improve the risk for heart disease or death.
The popularity of nutritional supplements skyrocketed in the United States over the past years, with about 3 in 4 people currently taking them. Ironically, there’s only limited evidence on the efficacy of these supplements or if they’re safe to consume.
The reason we conducted this study was that millions of people in the United States and across the world consume supplements or follow certain dietary patterns, but there was no good-quality evidence to suggest that these interventions have any effect on cardiovascular protection."
Safi Khan, assistant professor, West Virginia University School of Medicine
Few supplements show health benefits for the heart
The researchers analyzed data from 277 randomized controlled trials to determine the effects of 18 nutritional supplements and 8 diets on the health of nearly 1 million adults. Findings show that of the 16 dietary supplements, only two showed beneficial effects on heart health, namely omega-3 long-chain fatty acids and folic acid.
"The majority of supplements have no effect on improving survival or reducing the risk of heart attack or stroke," Dr. Safi Khan, an assistant clinical professor of internal medicine at West Virginia University, said in a statement.
In fact, the researchers found that omega-3 long chain fatty acids may help protect against heart attack, or myocardial infarction and coronary heart disease. Moreover, the risk of stroke lessened in people who took folic acid supplements.
Other supplements namely selenium, vitamin B6, vitamin E, vitamin C, iron, and vitamin A, among others, show no significant effect on heart health.
Some supplements may even cause harm
Some supplements may even cause potential harm. For example, taking both vitamin D and calcium may increase the risk of stroke. However, taking vitamin D or calcium alone seemed to have no effect on cardiovascular outcomes or mortality.
Many popular diets have no beneficial effects on heart health, too
Supplements aside, the researchers also focused on dietary interventions to see if they are beneficial for the heart. That’s because there’s a little body of knowledge and high-quality evidence that diets are really heart-healthy.
Most diets, like modified fat intake, the Mediterranean diet, and reduced saturated fat intake, had no effect on the heart at all. In fact, the only beneficial diet is the reduced salt intake, but only in those with normal blood pressure. People with hypertension are already at risk for various cardiovascular events.
Reduced salt intake was associated with improving overall survival and cardiovascular mortality. This is something that can be backed up with logic because there is a sufficient amount of data, in various studies, that shows low salt intake basically improves hypertension, which directly influences the cardiovascular outcome."
One of the most surprising findings was that the Mediterranean diet didn’t provide heart health protection. The diet is renowned and popular for its promise to reduce the risk of various ailments, including cardiovascular disease.
A well-balanced lifestyle and diet can improve heart health
Overall, a well-balanced diet is still the best way to provide the body with the needed nutrients and vitamins. The researchers conclude:
Other nutritional supplements, such as 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."
The researchers hope that the study findings urge further investigation on the intake of nutritional supplements and the practice of certain dietary interventions, especially for those who are at risk for heart disease and stroke. Some experts also warn that certain diets may not be good for the heart and only eating a healthy balanced diet is the key to overall health.
Khan, S., Khan, M., Riaz, H., Valavoor, S., Zhao, D., Vaughan, L., Okurintemi, V., Riaz, I., Khan, M.S., Kaluski, E., Murad, H., Blaha, M., Guallar, E., and Michos, E. (2019). Effects of Nutritional Supplements and Dietary Interventions on Cardiovascular Outcomes: An Umbrella Review and Evidence Map. Annals of Internal Medicine. DOI: 10.7326/M19-0341.