Bone Fractures & Vitamin D — Can Supplements Actually Help?

Supporting bone health has to be vitamin D’s claim to fame—thanks to its role in aiding calcium absorption. What’s less known is how vitamin D status impacts one's likelihood of experiencing a break (or fracture) in a bone. 

Bone fractures are unfortunately a common concern as people get older. With age, bone density and quality weaken and the bones become more fragile and prone to breaking. In fact, up to 50% of women and 22% of men1 are expected to experience a fracture in their lives. 

So if vitamin D is good for bone health, then increasing vitamin D intake must aid in preventing fractures, right? Well, considering that most people are deficient or insufficient in this vitamin, and getting adequate quantities from the sun or food alone is unlikely, mindbodygreen does believe that pretty much everyone would benefit from a vitamin D supplement. 

Now, most of the data show that low levels of vitamin D in the blood increase your risk of bone fractures. For reference, vitamin D deficiency is when blood levels are at or below 20 ng/mL2, and 30 ng/mL2 is considered the upper end of insufficiency (or low vitamin D levels). 

A large study from 2017 found a low vitamin D level was linked to a 25% increased risk of total bone fracture3 and a 48% greater risk of hip fracture. 

And researchers of a 2020 meta-analysis of 20 studies including almost 42,000 people over 60 years of age found that people with a more favorable vitamin D status were 11% less likely to have a hip fracture1. (The same level of protection wasn’t seen for total fracture risk though.) 

However, studying vitamin D supplementation as it directly relates to bone fractures has been challenging, and there’s debate within the scientific community on the role it plays. That’s because some studies show supplementation is beneficial while others don’t5. 

This is at least partially due to discrepancies in how studies are set up from the start including how much vitamin D study participants take (800, 1,000, or 4,000 IU?), how often, and for how long.  

For example, a 2022 meta-analysis pooled data from 32 studies and found a 13% lower risk of fractures (related to bone loss) and falls with 800 IU of daily vitamin D supplementation, and a 22% lower risk when 1,000 IU was taken daily6. And supplementation was the most beneficial for those who had a known deficiency before supplementation began.  

A review published in 2020 found a similar (minimum) vitamin D dose to be beneficial but emphasized the importance of pairing it with a calcium supplement7. 

Right now, around 29% of U.S. adults are considered straight-up vitamin D deficient8, while 41% are vitamin D insufficient8. 

So most people need a supplement to first correct that inadequacy in the diet. From there, the purpose of supplementation is to achieve vitamin D sufficiency (levels at 50 ng/mL or more) for life. And that requires a dose of about 5,000 IU a day.

We reached the conclusion of 5,000 because research has demonstrated that supplementing with 1,000 IU of vitamin D39 raises the average adult's blood levels of vitamin D level by approximately 10 ng/ml, which means it takes 5,000 IU of vitamin D3 per day to raise your level to that goal of 50 ng/ml. 

Given the ubiquity of vitamin D inadequacy and the key role vitamin D plays in the body, we think almost everyone would benefit from a high-quality supplement.