Vitamin D and calcium supplements have long been promoted as a simple way to keep bones strong and prevent fractures. Millions of adults take them every day, especially as they get older and become more concerned about osteoporosis and bone loss.
Because calcium is a major building block of bone and vitamin D helps the body absorb calcium, many people assume that taking supplements will automatically reduce their risk of fractures. However, a major new review published in The BMJ suggests that the benefits may be much smaller than previously believed.
Why Vitamin D and Calcium Are Important for Bones
Bones are constantly being broken down and rebuilt throughout life. Calcium helps provide the strength and structure that bones need, while vitamin D supports calcium absorption and healthy bone metabolism.
Studies have shown that people with low calcium intake or low vitamin D levels often have lower bone density and a greater risk of fractures. These findings helped make vitamin D and calcium supplements some of the most commonly used supplements worldwide.
But having an important role in bone health does not necessarily mean that extra supplementation will prevent fractures in everyone.
What the Research Discovered
Researchers reviewed 69 randomized controlled trials involving more than 153,000 adults. The goal was to determine whether calcium supplements, vitamin D supplements, or a combination of both could reduce fractures and falls.
The results showed that the benefits were limited.
Vitamin D Alone
Vitamin D supplementation did not significantly reduce the risk of:
- Any fracture
- Hip fractures
- Vertebral fractures
- Non-vertebral fractures
- Falls
The researchers concluded that routine vitamin D supplementation is unlikely to provide meaningful fracture protection for most adults living in the community.
Calcium Alone
Calcium supplements produced similar results.
The review found little to no reduction in fracture risk or falls among people taking calcium alone. While some individual studies suggested possible benefits, the overall evidence showed that calcium supplementation by itself offers limited protection for most adults.
Vitamin D and Calcium Together
The combination of vitamin D and calcium showed the most promising results.
Researchers found a small reduction in overall fracture risk when both supplements were taken together. However, the improvement was modest and considered too small to be clinically meaningful for most people.
The combination also did not significantly reduce the risk of falls.
Why Earlier Studies May Have Looked More Promising
Much of the excitement around vitamin D and calcium came from earlier studies involving very elderly adults living in nursing homes or long-term care facilities.
These individuals often had:
- Very low vitamin D levels
- Low calcium intake
- Higher rates of osteoporosis
- Greater fracture risk
Because they started at a much higher risk level, supplementation appeared to have a greater impact. Later studies involving healthier adults living independently generally found much smaller benefits.
Bone Health Requires More Than Supplements
The findings do not mean vitamin D and calcium are unimportant. Both nutrients remain essential for healthy bones.
However, the review suggests that supplements alone are unlikely to be the answer for preventing fractures in most adults.
Other important ways to support bone health include:
- Regular weight-bearing exercise
- Strength training
- Eating a balanced diet
- Preventing falls
- Getting appropriate treatment for osteoporosis when needed
For people with diagnosed osteoporosis or vitamin D deficiency, healthcare providers may still recommend supplementation as part of a broader treatment plan.
The Bottom Line
This large review found that vitamin D alone, calcium alone, or the combination of both provides little to no meaningful protection against fractures and falls for most adults. While taking both together may offer a small benefit, the effect appears too modest to make a major difference for the general population.
For most people, maintaining strong bones is likely to depend more on healthy lifestyle habits, proper nutrition, regular physical activity, and appropriate medical care than on supplements alone.
Source:
Morin O, Delisle K, Dubois N, et al. Effect of calcium, vitamin D, or combined supplementation on fractures and falls in adults: systematic review and meta-analysis of randomised controlled trials. BMJ. 2026;393:e088050. Accessed by: https://www.bmj.com/content/bmj/393/bmj-2025-088050.full.pdf
