Vitamin D plus calcium may increase risk of stroke, finds study

Vitamin D plus calcium may increase the risk of stroke, find a study conducted to evaluate the effects of dietary supplements on health.

Nowadays people are blindly going for multiple dietary supplements in a bid to stay healthy and compensate for the nutritional requirements. A study published in the Annals of Internal Medicine reported that combined Vitamin D plus calcium might increase the risk for stroke, while reduced salt intake, omega-3 LC-PUFA use, and folate supplementation could reduce the risk for some cardiovascular outcomes in adults.

Vitamin D the sunshine vitamin is known to be beneficial for bone health. Vitamin D comes from foods such as salmon, tuna, mackerel, egg yolks, and beef liver, or in fortified foods such as milk, cereal and some orange juices. Another way to get the vitamin is by spending time outdoors, in sunlight. The body manufactures its own vitamin D when the skin is exposed to sunlight.

The researchers conducted the study to evaluate the role of nutritional supplements and dietary interventions in preventing mortality and cardiovascular disease (CVD) outcomes as the same is unclear.

In this massive new analysis of findings from 277 clinical trials using 24 different interventions, Johns Hopkins Medicine researchers say they have found that almost all vitamin, mineral and other nutrient supplements or diets cannot be linked to longer life or protection from heart disease.

The study aimed at examining the evidence about the effects of nutritional supplements and dietary interventions on mortality and cardiovascular outcomes in adults.

The vitamin and other supplements reviewed included: antioxidants, ?-carotene, vitamin B-complex, multivitamins, selenium, vitamin A, vitamin B3/niacin, vitamin B6, vitamin C, vitamin E, vitamin D alone, calcium alone, calcium and vitamin D together, folic acid, iron and omega-3 fatty acid (fish oil). The diets reviewed were a Mediterranean diet, a reduced saturated fat (less fats from meat and dairy) diet, modified dietary fat intake (less saturated fat or replacing calories with more unsaturated fats or carbohydrates), a reduced-fat diet, a reduced salt diet in healthy people and those with high blood pressure, increased alpha-linolenic acid (ALA) diet (nuts, seeds, and vegetable oils), and increased omega-6 fatty acid diet (nuts, seeds and vegetable oils). Each intervention was also ranked by the strength of the evidence as high, moderate, low or very low-risk impact.

Key findings

• Nine systematic reviews and 4 new RCTs were selected that encompassed a total of 277 trials, 24 interventions, and 992 129 participants.


• A total of 105 meta-analyses were generated.


• There was moderate-certainty evidence that reduced salt intake decreased the risk of all-cause mortality in normotensive participants and cardiovascular mortality in hypertensive participants.


• Low-certainty evidence showed that omega-3 long-chain polyunsaturated fatty acid (LC-PUFA) was associated with reduced risk for myocardial infarction and coronary heart disease.


• Folic acid was associated with a lower risk for stroke, whereas calcium plus vitamin D increased the risk for stroke; moderate certainty.


• 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 (very low– to moderate-certainty evidence).

"The panacea or magic bullet that people keep searching for in dietary supplements isn't there," says senior author of the study Erin D. Michos, M.D., M.H.S., associate director of preventive cardiology at the Ciccarone Center for the Prevention of Cardiovascular Disease and associate professor of medicine at the Johns Hopkins University School of Medicine. "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."

"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," says lead author Safi U. Khan, M.D., an assistant professor of Medicine at West Virginia University.