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The Vit D Story Now a Fairytale

It wasn’t that long ago that vitamin D appeared to be the panacea for everything from preventing MS to reducing the risk of diabetes.

But the one area where we thought the benefit of this vitamin was not up for debate was bone health.

It has been proven – lack of vitamin D causes rickets. It has been proven that vitamin D is important in bone metabolism and turnover. And it has been proven the people with low bone density are more likely to experience fractures. Therefore add vitamin D and improve bones, right? Wrong!

The latest meta-analysis of more than 80 randomised controlled trials shows that vitamin D supplementation does not prevent fractures or falls, and does not have any consistently clinically relevant effects on bone mineral density. This comes as a bit of a surprise, to say the least.

According to the systematic review, vitamin D had no effect on total fractures, hip fractures, or falls among the 53,000 participants in the pooled analysis.

And it didn’t matter if higher or lower doses of vitamin D were used, the New Zealand researchers reported in The Lancet.

In looking for a reason for the lack of an effect from supplementation, previous explanations such as baseline 25OHD of trial participants being too high, or the supplement dose being too low, or the trial being done in the wrong population just don’t hold water. The sheer number and variety of trials included in this meta-analysis has meant all of these possible confounders have been accounted for.

“The trials we included have a broad range of study designs and populations, but there are consistently neutral results for all endpoints, including the surrogate endpoint of bone mineral density,” they said.

Consequently, the researchers said future trials were unlikely to alter these conclusions.

“There is little justification to use Vitamin D supplements to maintain or improve musculoskeletal health,” they stated.

And while they acknowledge the clear exception to this is in the case of the prevention or treatment of rickets and osteomalacia, in general clinical guidelines should not be recommending vitamin D supplementation for bone health.

The conclusion appears quite emphatic and definitive, and it is supported in an accompanying commentary by a leading US endocrinologist.

“The authors should be complimented on an important updated analysis on musculoskeletal health,” said Dr Chris Gallagher from Creighton University Medical Centre, Omaha in the US.

But he suggests many Vitamin D supporters will still be flying the flag for supplementation, pointing to the multiple potential non-bony benefits.

“Within three years, we might have that answer because there are approximately 100,000 participants currently enrolled in randomised, placebo-controlled trials of vitamin D supplementation,” he said.

“I look forward to those studies giving us the last word on vitamin D.”

 

References

Bolland MJ, Grey A, Avenell A. Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. Lancet Diabetes Endocrinol. 2018 Oct 4. Available from: http://dx.doi.org/10.1016/S2213-8587(18)30265-1 [epub ahead of print]

Gallagher JC. Vitamin D and bone density, fractures, and falls: the end of the story? Lancet Diabetes Endocrinol. 2018 Oct 4. Available from: http://dx.doi.org/10.1016/S2213-8587(18)30269-9 [epub ahead of print]