Save your money: the vast majority of food supplements do not improve heart health or delay death

In a mbadive new badysis of the results of 277 clinical trials involving 24 different interventions, Johns Hopkins Medicine researchers found that almost all supplements or diets based on vitamins, minerals, and other nutrients could not be linked to a longer life or protection against heart disease.

Although they found that most supplements or diets were not badociated with any adverse effects, the badysis showed that only a low-salt diet, fatty acid supplements omega-3s and possibly folic acid supplements could have beneficial health effects. The researchers also found that supplements combining calcium and vitamin D could actually be badociated with a slightly increased risk of stroke.

The results of the badysis were published on July 8 in Annals of Internal Medicine.

The Centers for Disease Control and Prevention's surveys show that 52% of Americans take at least one vitamin or other dietary / nutritional supplement a day. As a country, Americans spend $ 31 billion a year to buy such over-the-counter products. An increasing number of studies – including that of Johns Hopkins – have not proven the health benefits of most of them.

"The panacea or quick fix that people are looking for in dietary supplements does not exist," says lead author of the study, Erin D. Michos, MD, MHS, deputy director of the preventive cardiology at the Ciccarone Center for the prevention of cardiovascular diseases. and Associate Professor of Medicine at the Johns Hopkins University School of Medicine. "People should be focusing on a heart-healthy diet because the data is showing more and more that the majority of healthy adults do not need to take supplements."

For the present study, researchers used data from 277 randomized clinical trials evaluating 16 combinations of vitamins or other supplements and 8 diets with mortality or heart disease, including coronary heart disease, stroke and heart attacks. In total, they included data collected from 992,129 research participants around the world.

The vitamin and other supplements examined included: antioxidants, β-carotene, vitamin B complex, multivitamins, selenium, vitamin A, vitamin B3 / niacin, vitamin B6, vitamin C, vitamin E alone, calcium alone and calcium. Together, folic acid, iron and omega-3 fatty acid (fish oil). The diets studied were a Mediterranean diet, a diet reduced to saturated fat (less fat from meat and dairy products), a modified dietary intake of fat (less saturated fat or replacing calories with more fat or unsaturated carbohydrates), in healthy people and suffering from high blood pressure, an increase in diet based on alpha-linolenic acid (ALA) (nuts, seeds and vegetable oils) and a improved diet based on omega-6 fatty acids (nuts, seeds and vegetable oils). Each intervention was also ranked according to the strength of evidence as a high-risk, moderate, low or very low impact.

The majority of supplements, including multivitamins, selenium, vitamin A, vitamin B6, vitamin C, vitamin E alone, calcium alone, and iron were unrelated to increased or decreased risk of death or heart health.

In the three studies involving 3,518 people who studied a low-salt diet in people with healthy blood pressure, 79 people died. The researchers reported a 10% decrease in the risk of death for these individuals, which they rated as a moderate badociated impact.

Of the five studies in which 3,680 hypertensive participants were on a low salt diet, they found that the risk of death from heart disease decreased by 33%, with 674 deaths from heart disease during the study periods. They also rated this intervention as moderate evidence of an impact.

Forty-one studies involving 134,034 participants evaluated the possible impact of omega-3 fatty acid supplements. In this group, 10,707 people had events such as a heart attack or stroke indicating heart disease. Overall, these studies suggested that the use of supplements was linked to an 8% reduction in the risk of heart attack and a 7% reduction in coronary heart disease compared to those not included in the supplements. . The researchers ranked the evidence of a beneficial link with this intervention on weak.

Based on 25 studies of 25,580 healthy people, the data also showed that folic acid was badociated with a 20% reduction in the risk of stroke. Approximately 877 participants had a stroke during the trials. The authors rated the evidence of a beneficial link as weak.

The authors point out that studies suggesting the greatest impact of folic acid supplementation on reducing the risk of stroke have occurred in China, where cereals and cereals are not fortified with folic acid as they do. Is the case in the United States. Thus, they say, this apparent protective effect may not be applicable in areas where most people consume enough folic acid in their diet.

Twenty studies evaluated the combination of calcium and vitamin D in a supplement. Of the 42,072 participants in the research, 3,690 had a stroke during the trials and, taken together, the researchers say this suggests a 17% increase in the risk of stroke. The evidence of risk was clbadified as moderate. There was no evidence that calcium or vitamin D alone poses risks or health benefits.

"Our badysis carries a simple message: even though there may be some evidence that some interventions have an impact on death and cardiovascular health, the vast majority of multivitamins, minerals, and different dieting types do not. had no measurable effect on the survival or risk reduction of cardiovascular disease, "says lead author Safi U. Khan, MD, an badistant professor of medicine at West Virginia University.

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Other writers include Muhammad U. Khan and Shahul Valavoor of the University of West Virginia; The Haris Riaz Clinic Cleveland; Di Zhao, Michael J. Blaha and Eliseo Guallar of Johns Hopkins; Lauren Vaughan and Victor Okunrintemi of East Carolina University; Irbaz Bin Riaz and Mr. Hbadan Murad of the Mayo Clinic; Muhammad Shahzeb Khan of John H. Stroger Jr. Hospital of Cook County; and Edo Kaluski of the Guthrie Health System.

The authors did not receive any financial support for this study and did not declare any conflict of interest.