Oxford study reveals potential pitfalls
A study published in November 2020 on 54,898 people living in the UK,1982 of whom were vegan, found a greater risk of total and hip fractures in vegans compared to meat eaters after an average follow-up of 17.6 years.1
Excluding animal products does not guarantee health
The authors were able to attribute some of the risk of fractures to low BMI and lower calcium and protein intakes among vegans. A relatively large number of vegans – 17% of vegan men and 28% of vegan women – had BMI below 20, which might indicate illness or low muscle mass and could negatively affect bone density. Notably, when they divided the vegans into groups by BMI, a significantly higher risk of total and hip fractures was only found in vegans with BMI below 22.5. Of course, overweight people carrying more weight have bigger muscles and bones and less fractures—but they don’t live as long.2,3 The question remains, can we get enough protein for excellent muscle and bone density, maintain a lifespan favorable BMI and still prevent fractures.
In this study, the average protein intake was 12.9% and 13.5% of calories for vegan men and women (which may be a bit low for the elderly) and 16.0% and 17.3% for meat eaters. Calcium intake was 1058 and 989 mg/day for meat eating men and women and 611 and 580 mg/day for vegan men and women. This low calcium intake likely reflects insufficient green vegetable intake by the vegans in the study.
The study’s disclaimer
The authors noted these factors – BMI, calcium intake, and protein intake – did not fully explain the difference in fracture risk between meat eaters and vegans, saying additional unknown factors likely also contributed.
For example, the researchers had no information on what supplements participants were taking or what type of exercise they engaged in. Rates of regular exercise were low in all groups but higher in vegans; 29% of meat eaters and 41% of vegans reported engaging in “moderate or high physical activity.”
Other contributors to bone health
Insufficient vitamin D, strength training, or intake of green vegetables and other bone-protecting plant foods could potentially be contributors. In other studies, diets higher in vegetables, fruits, minerals, and phytochemicals are linked to better bone health.4-6
Related: Preventing Osteoporosis
Plant protein from beans, nuts, and seeds
Vegans did consume more legumes, nuts, vegetables, and fruits than meat eaters, but on average, vegetable intake was only 173-200 g/day, which is less than two cups of vegetables daily.
Average legume intake was 30 g/day, which is only one-sixth of one cup of beans or lentils. Average intake of nuts was less than one ounce/day, and seed intake was not mentioned in the study. This low intake of whole plant foods suggests the vegans in the study were likely getting too many calories from refined carbohydrates and processed foods.