Mark Bolland, an associate professor at Auckland University’s medical and health sciences faculty most recently co-authored with long-time collaborator Ian Reid, a professor at Auckland, a systematic review in Medical Journal of Australia.
After reviewing the evidence of both efficacy and safety of calcium and vitamin D supplements, the paper bluntly concludes that while vitamin D has a place in the prevention of osteomalacia in individuals with specific risk factors, calcium supplements have “very little place” in modern medical practice.
“The use of calcium supplements in individuals without specific bone pathology does not have a sound evidence base, and the safety concerns suggest that the net effect could be negative,” Reid and Bolland wrote.
Calcium supplements, they wrote, are frequently associated with gastrointestinal symptoms, particularly constipation, and they have also been reported to double the risk of hospital admissions related to abdominal symptoms.
In one study they reviewed, “calcium and vitamin D increased the risk of kidney stones by 17%. There is evidence that calcium supplements increase the risk of myocardial infarction and, possibly, stroke, although this remains subject to controversy”.
In addition, they found calcium supplements to be frequently associated with gastrointestinal symptoms, particularly constipation. These have also been reported to double the risk of hospital admissions related to abdominal symptoms.
Bolland said the findings had not so far come under fire.
“This time I think no one has really had any criticism of what we found. It’s been quite a distinct change compared to what people had been saying previously,” Bolland said.
“Perhaps time has past and people are looking at the evidence for themselves and come to the view that it is pretty clear that there isn’t much of a role for calcium and vitamin D.”
Last year Bolland co-authored the largest meta-analysis of its kind to date, of 81 randomised trials, which concluded that vitamin D supplementation does not prevent fractures or falls, or improve bone mineral density in adults.
Published in The Lancet Diabetes & Endocrinology journal, it was another of upwards of a dozen equally controversial reviews the endocrinologist had worked on.
Bolland’s work into this area started at a time when calcium and vitamin D were routinely being prescribed around the world for the prevention and treatment of osteoporosis. Over time, calcium scripts have become less common, at least in New Zealand, but vitamin D continues to be widely recommended by doctors.
Bolland said the support of these medications were a scientific “dogma” over the last 30 or so years.
“A lot of people struggle to understand why we say that you don’t need to take them. The reason we say this is that the clinical trials that have been done show you don’t get benefit from these supplements, so we should stop prescribing them routinely,” Bolland said.
Australian researchers in particular had “openly and loudly disagreed” with the findings of Bolland and his colleague.
“So it’s interesting that some people in response to the latest review now say otherwise healthy people don’t need to take calcium and vitamin D,” he said
“Still, I’ve also seen some comments emphasising that for people with osteoporosis, you should still be prescribing the supplements, which is quite different to what we said in the review,” he added.
Source: Medical Journal of Australia
“Controversies in medicine: the role of calcium and vitamin D supplements in adults”
Authors: Ian R Reid, Mark J Bolland