Does vitamin D supplementation protect people from bone fractures, cancer and cardiovascular disease? Researchers wrote in Annals of Internal Medicine in two separate articles that so far there is no compelling evidence to support any of these claims.

Article 1 – studies have indicated that vitamin D supplementation may play a role in reducing the risk of developing cancer and bone fractures.

Mai Chung PhD and team from Tufts Medical Center, Boston, Massachusetts, gathered data on 19 clinical trials and 28 observational studies, to find out what the benefits and harms of vitamin D on its own or combined with calcium might be in cancer outcomes and fractures in adult patients.

They found that fracture risk in elderly individuals was reduced when they took vitamin D combined with calcium supplementation, but did not change when vitamin D was taken on its own.

They found that evidence supporting vitamin D supplementation’s role in preventing cancer was poor. Some data indicated that perhaps vitamin D might reduce total cancer risk – but the evidence was limited and further research is required.

Too much vitamin D can raise the chances of developing kidney and urinary tract stones, raising concerns about what the proper dosing should be.

The authors explained that the USPSTF (United States Preventive Services Task Force) will soon be making a recommendation statement on vitamin D supplementation, and that their current findings will be used. The USPSTF’s finalized recommendation will be published in Annals of Internal Medicine.

Article 2 – Vitamin D supplementation and cardiovascular disease prevention?

Cora McGreevy, and team from the Royal College of Surgeons in Ireland say that there is no evidence to support claims that vitamin D supplementation helps prevent cardiovascular disease.

The authors explain that vitamin D deficiency has become a progressively more common condition. However, even though vitamin D deficiency is well established, there is no standard guideline to define what vitamin D insufficiency is.

There are several factors linked to vitamin D deficiency, including low ultraviolet light exposure, low socioeconomic status, being female, being elderly, and not eating the right foods.

Vitamin D deficiency has been associated with high blood pressure (hypertension), stroke, myocardial infarction, diabetes, congestive heart failure, atherosclerosis, and endothelial dysfunction.

The authors gathered data on published reviews dated from 1985 to 2011 to determine what effect vitamin D supplementation might have on cardiovascular outcomes.

They found that among the very few randomized controlled human trials that evaluated vitamin D replacement therapy on cardiovascular outcomes, results were contradictory or inconclusive.

They believe further randomized, controlled human trials should be carried out that specifically determine what the role of vitamin D is in reducing cardiovascular disease.

Written by Christian Nordqvist