The increase in risk may arise from meat-free diets tending to have less protein, which helps build muscle mass, and possible deficiencies in vitamins and minerals, such as calcium and vitamin B12, which help strengthen bones.
Women are more likely to break their hips than men, especially as they get older, because after the menopause, levels of the sex hormone oestrogen fall, leading to weaker bones. Broken hips are a significant cause of deaths in older people as they are hard to recover from and can result in extended immobility and health complications. “The effect on health is pretty big,” says James Webster at the University of Leeds, UK.
Previous studies have suggested that vegetarians and vegans have weaker bones, so Webster’s team took advantage of a large ongoing study that has tracked the health and lifestyle of over 26,000 women in the UK for about 20 years. They were aged between 35 and 69 at recruitment, and none were transgender as far as the researchers know.
Overall, about 3 per cent of participants broke their hip during that time. Those who were vegetarian had a 33 per cent higher risk of this happening compared with those who consumed meat at least five times a week.
There was no difference in risk between regular meat eaters and those who ate lesser amounts, or just ate fish. Vegans weren’t included in the study.
Other research has found that being vegetarian is better for health in different ways – for instance, it is linked with a lower risk of heart disease. All such studies, including the latest one, are observational, however, and so can’t prove that diet causes different health patterns – only that there are correlations.
Such studies can make meat-free diets seem more beneficial than they really are because vegetarians usually have healthier lifestyles in other ways, such as avoiding smoking and heavy drinking. The best kind of medical evidence comes from randomised trials, but these are hard to do for a major dietary choice such as whether or not to eat meat.