Vitamin D Supplements Don’t Improve Bone Health, Major Study Finds
There is little justification for using vitamin D supplements to maintain or improve musculoskeletal health, scientists have suggested.
Researchers said taking the supplement would only be useful for high risk groups who want to prevent rare conditions such as rickets and osteomalacia, which can occur due to vitamin D deficiency.
The study, published in the Lancet Diabetes and Endocrinology journal, also found no differences in the effects of higher versus lower doses of vitamin D.
Vitamin D helps regulate the amount of calcium and phosphate in the body, which are needed to keep bones, teeth and muscles healthy.
The Department of Health currently recommends that all children under five should take a daily supplement, along with pregnant and breastfeeding women, and older people who are not often outdoors —f or instance if they are frail, housebound, or live in a care home.
It suggests that other adults should take a supplement during the autumn and winter, when they are less likely to get sunlight on their skin.
Between late March/early April to the end of September, most people can get all the vitamin D they need through sunlight and a balanced diet.
The authors of the study said clinical guidelines that recommend vitamin D supplementation for bone health should be changed to reflect the best available evidence, noting that their study was the largest meta-analysis ever carried out, with data from 81 randomized controlled trials.
Lead author Dr. Mark Bolland of the University of Auckland, New Zealand, said:
Since the last major review of evidence in 2014, more than 30 randomized controlled trials on vitamin D and bone health have been published, nearly doubling the evidence base available.
Our meta-analysis finds that vitamin D does not prevent fractures, falls, or improve bone mineral density, whether at high or low dose.
Clinical guidelines should be changed to reflect these findings.
On the strength of existing evidence, we believe there is little justification for more trials of vitamin D supplements looking at musculoskeletal outcomes.
The majority of the trials that were analyzed looked at vitamin D alone (not prescribed in conjunction with calcium supplements) and lasted one year or less.
Most included women aged over the age of 65 (77% of trials) who lived locally and who received daily doses of more than 800 international units per day (68% of trials).
They found there was no clinically meaningful effect of vitamin D supplementation on total fracture, hip fracture, or falls.
In secondary analyses looking at bone density, there were small differences for lumbar spine, femoral neck, and for total body, but none of these were clinically relevant.
The authors noted that the data were collected differently for falls in different trials, which might affect the study findings, while they also pointed out that smaller trials of shorter duration tended to find stronger effects of vitamin D compared to larger trials of longer duration.
Public Health England (PHE) said around a fifth of the UK population has blood levels of vitamin D indicating a risk of poor musculoskeletal health and thus the UK’s precautionary advice remains appropriate.
Professor Louis Levy, PHE’s head of nutrition science, said:
This study highlights the importance of maintaining adequate levels of vitamin D to reduce the risk of poor musculoskeletal health.
With a fifth of people in the UK showing concerning vitamin D levels, Government advice is to achieve this from sunshine and a healthy balanced diet during summer and spring.
During autumn and winter, those not consuming foods naturally containing or fortified with vitamin D should consider a 10mg supplement.