Dietary supplements may do more harm than good: Study

Researchers have found that intake of some vitamins, minerals and other dietary supplements may not benefit the heart and, in some cases, may even prove to be injurious.

According to the study published in the journal Annals of Internal Medicine, supplements combining calcium and vitamin D may be linked to a slightly increased stroke risk.

However, there was no evidence that calcium or vitamin D taken alone had any health risks or benefits.

"Our analysis carries a simple message that although there may be some evidence that a few interventions have an impact on death and cardiovascular health, the vast majority of multivitamins, minerals and different types of diets had no measurable effect on survival or cardiovascular disease risk reduction," said study lead author Safi U. Khan, Assistant Professor at the West Virginia University.

For the study, the researchers used data from 277 randomised clinical trials that evaluated 16 vitamins or other supplements and eight diets for their association with mortality or heart conditions including coronary heart disease, stroke and heart attack.

They included data gathered on 992,129 research participants worldwide.

The analysis showed possible health benefits only from a low-salt diet, omega-3 fatty acid supplements and possibly folic acid supplements for some people.

"The panacea or magic bullet that people keep searching for in dietary supplements isn't there," said senior author of the study Erin Michos from Johns Hopkins University School of Medicine in the US.

"People should focus on getting their nutrients from a heart-healthy diet, because the data increasingly show that the majority of healthy adults don't need to take supplements," Michos said.

According to Abhishek Singh, Consultant Cardiologist at Columbia Asia Hospital in Ghaziabad, dietary supplements do not have a measurably positive impact on cardiac health.

"It's more important to follow a healthy dietary regimen and avoid foods that are bad for the heart. Trans fatty acids are harmful and have to be curtailed. Refined sugars and simple carbohydrates are to be kept at a minimum," Singh told IANS.

The doctor suggested that people should include more green vegetables in their diet. They are rich in vitamin K and dietary nitrates, which help protect the arteries and reduce blood pressure, he said.

"Studies like this raise concerns about harm from calcium and Vitamin D supplement use. As far as Vitamin D supplements (without calcium) are concerned, there has been no evidence on whether it has any impact on cardiovascular disease risk reduction," Anupama Singh, Senior Consultant, Internal Medicine at Vimhans Nayati Super Specialty Hospital in Delhi, told IANS.

"The quality of the evidence base of these various nutritional supplements and dietary interventions still needs to be evaluated to ascertain the effectiveness of the study," she added.