Providing vitamin D to older people does not help prevent osteoporosis in general but may help strengthen bones in those with a serious vitamin D deficiency, suggest a new study.
Researchers from the University of Auckland, New Zealand and Harvard Medical School in the US set out to explore whether giving older adults a higher dose of vitamin D could help boost bone density.
“We set out to determine whether a higher dose of vitamin D influences bone density”
More than 400 people aged 50 to 84 took part in a trial where they were either given monthly doses of vitamin D or a placebo.
“Trials in the community have not consistently shown that vitamin D supplements improve bone density or reduce the risk of fracture,” said Professor Ian Reid, from the University of Auckland.
“So we set out to determine whether a higher dose of vitamin D influences bone density or whether benefit is dependent on the level of vitamin D already present in the individual,” he said.
The results of the research, announced at the European Calcified Tissue Society Congress held in Austria, suggest there is little value in blanket provision of vitamin D supplements to older people when it comes to preventing bone weakness.
However, targeting those with low levels of the vitamin in their system may have benefits.
The researchers recorded participants’ existing vitamin D levels. During the two-year trial they went on to measure changes in bone density in the lower spine and other parts of the body.
‘Target’ supplements at people with vitamin D deficiency
For those with vitamin D levels above a certain threshold there was no real change in bone density among those getting the supplement compared to the control group.
However, for those at or below this threshold, researchers saw a change in bone density of around 2%.
They say this shows there may be benefits in taking supplements for those with a lack of vitamin D and said future research should look into this.
“It was clear to us that future trials of vitamin D supplements in older adults should focus on those who have baseline vitamin D levels equal to or below 30 nmol per litre and that the findings represent a significant step towards defining vitamin D deficiency for bone health in older adults,” said Professor Reid.