Researchers studied whether fish oil supplements could help prevent broken bones and strengthen bones in middle-aged and older adults. Over 25,000 people took either fish oil supplements or a placebo pill for about 5 years. The results showed that fish oil supplements did not reduce the risk of fractures or significantly improve bone strength compared to placebo. While fish oil caused a tiny increase in overall bone density, it didn’t translate to fewer broken bones or stronger bones where it matters most. This finding surprises many people because earlier lab studies suggested fish oil might help bones.

The Quick Take

  • What they studied: Does taking fish oil supplements help prevent broken bones and make bones stronger in healthy adults?
  • Who participated: 25,871 healthy American men aged 50 and older and women aged 55 and older with no history of cancer, heart disease, or bone problems. Average age was 67 years old.
  • Key finding: Fish oil supplements did not reduce the risk of breaking bones (including hip fractures) compared to placebo over 5+ years of use. While whole body bone density increased slightly (0.03% vs -0.41%), this tiny difference didn’t prevent fractures or improve bone strength where it matters.
  • What it means for you: If you’re taking fish oil supplements hoping to prevent broken bones, this research suggests they probably won’t help with that goal. However, fish oil may have other health benefits worth discussing with your doctor. Don’t stop taking supplements without talking to your healthcare provider first.

The Research Details

This was a large, high-quality randomized controlled trial called VITAL. Researchers randomly assigned people to take either fish oil supplements (1 gram per day) or identical-looking placebo pills. Neither the participants nor the researchers knew who was getting the real supplement versus the fake one, which helps prevent bias. The study lasted from 2011 to 2017, with people followed for an average of 5.3 years. Researchers carefully tracked all broken bones that occurred and had doctors confirm them. In a smaller group of 771 people, they also used special X-ray machines to measure bone density and strength at the start and after 2 years.

The fish oil used contained two main types of omega-3 fatty acids (EPA and DHA) in a specific ratio, similar to what you’d get from eating fatty fish. This design allowed researchers to see if fish oil specifically affects bone health in real people, not just in laboratory animals. The study included generally healthy people without bone disease, which means the results apply to average adults, not people with special bone problems.

Previous studies in animals and test tubes suggested omega-3 fatty acids might strengthen bones, but very few human studies had tested this. This research is important because it’s one of the largest and longest studies ever done on this question. By following thousands of people for years and carefully documenting broken bones, researchers could give a reliable answer about whether fish oil actually prevents fractures in real life. The study’s size and quality mean we can trust these results more than smaller or shorter studies.

This study is considered high-quality because: (1) it was randomized, meaning people were randomly assigned to groups, which reduces bias; (2) it was double-blinded, so neither participants nor researchers knew who got real supplements; (3) it included a large number of people (25,871), making results more reliable; (4) it followed people for over 5 years, long enough to see real health effects; (5) broken bones were confirmed by doctors rather than just reported by patients; (6) it was conducted by respected medical institutions. The main limitation is that the study only measured bone density in a small subset of 771 people, so those results are less certain than the fracture findings.

What the Results Show

The main finding was clear: fish oil supplements did not reduce the risk of broken bones. Over the 5+ year study period, people taking fish oil had the same number of total broken bones as people taking placebo (1.02 times as many, which is essentially the same). Hip fractures, which are especially serious in older adults, were actually slightly lower in the fish oil group, but this difference was so small it could easily be due to chance. Non-spine fractures also showed no difference between groups.

When researchers looked at bone density measurements in the smaller group of 771 people, they found a very small increase in whole body bone density with fish oil (0.03% increase versus a 0.41% decrease in the placebo group). However, this tiny difference—less than one-tenth of one percent—did not translate to stronger bones or fewer fractures. At the spine and hip, where fractures are most common and serious, there was no difference in bone density between groups.

Bone strength measurements at the forearm and shin bone showed no improvement with fish oil supplements. These measurements directly assess how resistant bones are to breaking, and fish oil made no difference. The researchers also measured the thickness of the outer layer of bone (cortical thickness), which is important for bone strength, and again found no benefit from fish oil.

The study found no serious side effects from taking fish oil supplements. Some people reported minor digestive issues or fish-flavored burps, but these were not serious. The study was originally designed to look at cancer and heart disease risk, and fish oil showed no major effects on those outcomes either. This suggests fish oil supplements are generally safe to take, even long-term, but they don’t appear to provide the bone health benefits that some people hope for.

This finding contradicts what many laboratory and animal studies suggested. In test tubes and in mice, omega-3 fatty acids appeared to help bone cells grow and strengthen bones. However, this VITAL study joins a growing body of evidence showing that what works in the lab doesn’t always work in real people. Some smaller human studies had suggested fish oil might help bones, but this large, well-designed study found no meaningful benefit. The results suggest that either the dose used (1 gram per day) isn’t enough, or the way omega-3 fatty acids work in animals doesn’t translate to humans, or both.

The study has several important limitations to consider. First, while 25,871 people is large, the study only measured detailed bone density and strength in 771 people, so those findings are less certain. Second, the study only lasted 5.3 years on average; longer-term effects are unknown. Third, the study included generally healthy people without bone disease, so results may not apply to people with osteoporosis or other bone conditions. Fourth, the fish oil dose (1 gram per day) is relatively modest; higher doses weren’t tested. Finally, the study couldn’t determine whether certain groups of people (like women after menopause or very elderly people) might benefit differently from fish oil, though the overall results showed no benefit.

The Bottom Line

Based on this evidence, fish oil supplements are not recommended specifically for preventing broken bones or strengthening bones in healthy adults. The evidence is strong (high confidence) that fish oil doesn’t reduce fracture risk. However, fish oil may have other health benefits for heart health that are worth discussing with your doctor. If you’re already taking fish oil for other reasons, you can continue safely, but don’t expect it to prevent broken bones. For bone health, proven strategies like getting enough calcium and vitamin D, doing weight-bearing exercise, and not smoking are more effective.

This finding matters most for healthy middle-aged and older adults considering fish oil specifically for bone health. If you’re worried about broken bones, this study suggests fish oil won’t help. However, people with diagnosed osteoporosis or those at very high risk for fractures should talk to their doctor about proven treatments like prescription medications. Younger people and those without bone concerns probably don’t need to worry about this finding. People taking fish oil for other reasons (like heart health) can continue, as this study doesn’t suggest it’s harmful.

This study followed people for 5+ years, so we can be confident that fish oil doesn’t prevent fractures within that timeframe. If fish oil were going to help bones, we would have seen it by now. Long-term effects beyond 5 years are unknown, but based on this evidence, waiting longer is unlikely to change the results.

Want to Apply This Research?

  • Track daily fish oil supplement intake (yes/no) alongside bone-healthy behaviors like calcium intake, vitamin D levels, weight-bearing exercise minutes, and any falls or injuries. This helps users see that while supplements are easy to track, actual bone health depends more on exercise, nutrition, and lifestyle.
  • Instead of relying on fish oil supplements for bone health, use the app to build proven bone-strengthening habits: track daily weight-bearing exercise (walking, dancing, strength training) for at least 30 minutes, log calcium-rich foods (dairy, leafy greens, fortified foods), monitor vitamin D intake, and record any falls to identify safety risks in your home.
  • Create a ‘Bone Health Dashboard’ that tracks the evidence-based factors that actually prevent fractures: exercise frequency, calcium and vitamin D intake, fall prevention measures, and medication adherence (if prescribed). Allow users to set reminders for bone-healthy behaviors rather than just supplement-taking, and celebrate progress on activities proven to strengthen bones.

This research suggests fish oil supplements do not prevent broken bones in healthy adults. However, this study doesn’t apply to people with diagnosed osteoporosis, severe bone loss, or other specific bone conditions. Always talk to your doctor before starting, stopping, or changing any supplements, especially if you have bone disease, take blood thinners, or have other health conditions. This information is for educational purposes and should not replace professional medical advice. Your doctor can recommend bone-strengthening strategies proven to work for your individual situation.