If you’re over 50, chances are that at some point a doctor, a pharmacist, or an ad has recommended taking calcium, vitamin D, or both to protect your bones. An analysis published in The BMJ, the most complete ever done on the topic, has just called into question whether that recommendation rests on the solid ground we all assumed.
The study, led by Olivier Massé and a team of Canadian researchers, pools 69 randomized clinical trials with 153,902 participants, nearly three times the data available in the most cited previous reviews. And the conclusion is an uncomfortable one for an industry worth billions of dollars a year: neither calcium, nor vitamin D, nor the combination of both meaningfully reduces the risk of fractures or falls.
The real benefit is essentially nil, even when it’s statistically significant. With calcium alone, the risk of any fracture barely budged (risk ratio of 0.91, with a confidence interval brushing against 1, meaning no clear effect). With vitamin D alone, the result was even more decisive: across more than 92,000 participants, and with the highest possible certainty of evidence, fracture risk was exactly the same as with placebo, 1.00. The combination of both did show a statistically significant difference, but one so small it would take treating 100 people for years to prevent a single additional fracture.
The best-designed trials are the ones showing the least benefit. The authors highlight something revealing: the more participants and the higher the quality of a trial, the closer its result came to zero. The first major study that popularized these supplements, published in the early 1990s, found notable reductions in hip fractures. But it was done with women averaging 84 years old, living in nursing homes, with extremely low vitamin D levels and calcium-poor diets, a profile very different from the average adult who buys these supplements at a pharmacy today.
This isn’t a correlation problem, it’s direct experimental evidence. Unlike observational studies, where you can never fully rule out some other factor explaining the relationship, these are randomized trials: one group was given the supplement and another a placebo, at random. That allows for talk of causation, not just association. And what these experiments show, with a certainty of evidence rated high in most cases, is that supplementation doesn’t change the outcome.
Nor is it a cost-free treatment. Calcium pills are hard to swallow and frequently cause constipation, bloating, or abdominal pain in older adults. One large trial linked it to more hospital admissions for digestive issues, and another found more kidney stones among people taking calcium and vitamin D together. In the UK alone, spending on vitamin D prescriptions rose from 13 million pounds in 2001 to 111 million in 2021, a jump that, according to this analysis, hasn’t translated into fewer broken bones.
The authors do qualify something important: their conclusions apply to the general population, not necessarily to people with diagnosed osteoporosis, those on specific medications for that condition, or those with confirmed severe vitamin D deficiencies, groups where evidence remains limited and where supplements may still make sense under medical supervision.
This article is for informational purposes only and does not replace the advice of a healthcare professional. If you take these supplements or are considering stopping them, talk to your doctor before changing anything.
Source: Massé O, Mercurio CM, Dupuis S, et al. “Calcium, vitamin D, or combined supplementation to prevent fractures and falls: systematic review and meta-analysis.” The BMJ, 2026. Open access (CC BY-NC). DOI: 10.1136/bmj-2025-088050
