(RxWiki News) Vitamin D supplements have been recommended to help prevent many serious conditions. But they actually might not be helping.
A recent review of previous studies found that vitamin D supplements with and without calcium did not significantly reduce the risk of heart disease, stroke, fracture, cancer or death.
"Tell your doctor about all nutritional supplements you use."
The lead author of this review was Mark J. Bolland, PhD, from the Bone and Joint Research Group in the Department of Medicine at the University of Auckland in New Zealand.
The review analyzed the results from 40 previously published studies on vitamin D supplements. All of these studies were published between January 2009 and January 31, 2013.
The studies all looked at the effects of vitamin D — with or without calcium — on heart attack and heart disease, stroke, cerebrovascular disease (affects the blood vessels that supply the brain), cancer, fracture and death.
The study periods ranged from one month to 12 years. The study participants' ages ranged from 53 years old to 89 years old.
The findings showed that vitamin D supplements with or without calcium did not reduce the risk of heart attack and heart disease, stroke and cerebrovascular disease, cancer or total fracture by more than 15 percent.
When it came to the risk of hip fractures only, vitamin D supplements without calcium did not reduce the risk, but vitamin D supplements without calcium reduced the risk by 16 percent compared to not taking vitamin D supplements, but this evidence was limited.
The authors of this review were uncertain whether or not vitamin D — with or without calcium — had any affect on the risk of death. Future studies are needed on this.
Professor Karl Michaëlsson, of Uppsala University in Sweden, wrote in a commentary that accompanied the study, "Without stringent indications — i.e. supplementing those without true vitamin D insufficiency — there is a legitimate fear that vitamin D supplementation might actually cause net harm."
This review was limited because the data from many of the reviewed studies were not the main outcomes of the studies.
This review was published on January 23 in The Lancet Diabetes & Endocrinology.
The Health Research Council of New Zealand provided funding.