New findings from the EPIC-Oxford study in the U.K. have raised questions about vegan diets and bone health. In this study, which included around 55,000 (mostly white) subjects, vegans had a 43% higher risk of fractures overall compared to nonvegetarians, as well as higher risks of hip, leg, and vertebral fractures.
The biggest difference was for hip fractures; vegans were more than twice as likely as people who ate meat to break their hip. Vegetarians and pesco-vegetarians (their diets include fish but no other meat) also had a higher risk of hip fracture, although not as high as vegans. Among the vegans, risk for fracture seemed to be greatest in women, especially post-menopausal women.
The average lower body weights of vegans was part of the explanation. More fat tissue can help cushion bones during a fall and is also associated with higher levels of estrogen, which is beneficial for bone health. It also creates a heavier load on the skeleton which may stimulate bone formation, although this depends on physical activity. But even when the researchers controlled for BMI, vegans had a higher risk for fracture in some BMI categories.
The vegans in this study had lower intakes of calcium and protein, two factors that are crucial for healthy bones. But again, lower intakes of these nutrients explained the findings only in part. When the analysis considered only subjects with calcium intakes that were at least 700 mg per day and protein intakes of at least 0.75 grams of protein per kg body weight per day, vegans were still more likely to experience a fracture.
As the authors of this study pointed out, estimation of calcium and protein intake by questionnaire is likely to involve some error. And the analysis didn’t include calcium supplements. Finally, the study did not look at the relationship of vitamin D or vitamin B12 intake to fracture risk. Low intakes of both these nutrients are linked to poorer bone health.
Even if we don’t have all the answers about why vegans in this study were at higher risk for fracture, we can make recommendations about what vegans (and non-vegans) can do to protect bone health. It’s tempting to embrace the popular principle that vegans will automatically meet all nutrient needs by consuming a varied plant-based diet, but it’s not true. Some nutrients require attention in vegan diets. And sometimes, eating fortified foods is helpful. Here is what you can do to protect your bones on a plant-based diet.
Get plenty of protein. The old studies suggesting that fracture rates are more prevalent in countries with higher protein intakes tells us much more about culture, ethnicity, and geography than about diet. Protein is good for bone health. Higher protein intake enhances calcium absorption and is associated with stronger bones and lower risk of fracture. Vegans should aim for at least 3 servings per day of legumes (beans, soyfoods, peanuts/peanut butter). If you’re older, and especially an older woman, it’s not a bad idea to strive for more.
Get adequate calcium. In Vegan for Life we recommend a simple approach: consume at least 3 cups per day of some combination of plant foods that are good sources of well-absorbed calcium. These include cooked leafy greens in the cabbage family (kale, turnip greens, bok choy, mustard greens, broccoli, and collards), calcium fortified plant milks, calcium-fortified juices, and calcium-set tofu. If you consistently fall short of this goal, consider a small calcium supplement, maybe 300 mg per day or so. If you track your calcium intake, be aware that consuming spinach, chard and beet greens can make it look like your diet is high in calcium. But because of their high oxalate content, most of the calcium in these foods isn’t absorbed.
Get adequate vitamin D. For almost everyone, this means taking a supplement providing 600 to 1,000 IUs vitamin per day.
Eat plenty of fruits and vegetables. These foods are sources of nutrients and compounds that are associated with improved bone health.
Take a vitamin B12 supplement following the guidelines here. (But you’re already doing this, right?)
Be moderate with alcohol intake. For those who do not have alcoholism, a glass of red wine with dinner is fine, but high intakes are associated with bone loss.
Stay physically active and especially do weight bearing exercise.
For more information about this study, see this article from the Vegetarian Resource Group.
Source: Tong TYN, Appleby PN, Armstrong MEG, et al. Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study. BMC Med. 2020;18(1):353.