People who live on vegetarian diets have slightly weaker bones than their meat-eating counterparts, Australian researchers said on Thursday.

A joint Australian-Vietnamese study of links between the bones and diet of more than 2,700 people found that vegetarians had bones five percent less dense than meat-eaters, said lead researcher Tuan Nguyen.

The issue was most pronounced in vegans, who excluded all animal products from their diet and whose bones were 6% weaker, Nguyen said. There was "practically no difference" between the bones of meat-eaters and ovolacto vegetarians, who excluded meat and seafood but ate eggs and dairy products, he said.

"The results suggest that vegetarian diets, particularly vegan diets, are associated with lower bone mineral density," Nguyen wrote in the study, which was published Thursday in the American Journal of Clinical Nutrition.

Nguyen, who is from Sydney's Garvan Institute for Medical Research and collaborated on the project with the Pham Ngoc Thach University of Medicine in Ho Chi Minh City, said the question of whether the lower density bones translated to increased fracture risk was yet to be answered.

"Given the rising number of vegetarians, roughly five percent (of people) in western countries, and the widespread incidence of osteoporosis, the issue is worth resolving," he said.