The study, published in the March 28 issue of the Archives of Internal Medicine, was led by Luigi Fontana, M.D., Ph.D., research instructor in medicine in the Division of Geriatrics and Nutritional Science. Fontana and colleagues studied 18 strict raw food vegans ages of 33 to 85. All ate a diet that not only lacked animal products but also included only raw foods such as a wide variety of vegetables, fruits, nuts, seeds, sprouted grains and legumes, dressed with olive oil. They had been on this diet for an average of 3.6 years.
The researchers compared them to people who ate a more typical American diet, including refined carbohydrates, animal products and cooked food. The groups were matched according to age, sex and socioeconomic status. In both groups, Fontana's team measured body mass index, bone mass, bone mineral density, markers of bone turnover, levels of vitamin D and inflammatory markers such as C-reactive protein and insulin-like growth factor 1 (IGF-1).
Those on the raw food diet had lower body mass indices and significantly lower bone mass in important skeletal regions such as the hip and lumbar spine, sites where low bone mass often means osteoporosis and fracture risk. But they didn't have other biological markers that typically accompany osteoporosis.
"For example, it is clear from research that higher rates of bone turnover equate to higher risk of fracture," Fontana says. "But in these people, although their bone mass is low, their bone turnover rates are normal."