This site is being redeveloped. For all the latest ABC Science content click here.

Site Navigation

●Video ●Audio ●Photos ●Explore by topic ●Ancient Worlds ●Being Human ●Energy & Transport ●Environment & Nature ●Health & Medical ●Innovation & Technology ●Space & Astronomy ●News in Science ●In Depth ●Dr Karl ●Great Moments in Science ●Dr Karl on triplej ●Karl Trek ●Sleek Geeks ●School's video prize ●Karl Who? ●Ask an Expert ●Bernie's Basics ●Quizzes & Games ●Teaching Science ●Lesson Plans ●Conundrums ●Demonstrations ●Careers ●Ace Day Jobs ●Talking Science ●Catapult on triplej ●Share ●Print News in Science

Vegan diet leads to less dense bones

Thursday, 2 July 2009 Nicky Phillips ABC

Eating a vegan diet may decrease your bone density, but not the rate of fracture, say Australian researchers (Source: iStockphoto)

●Osteoporotic fractures up mortality risk, Science Online, 04 Feb 2009 ●Expanded use of osteo drugs questioned, Science Online, 24 Jan 2008 ●Osteoporosis-steroid link confirmed, Science Online, 22 Mar 2001 ●Map: Sydney 2000 Vegans have lower bone densities than non-vegans, say Australian researchers. But the news isn't all bad, with the study finding an animal-free diet doesn't translate into more fractures. The findings, published today in the American Journal of Nutrition American Journal of Nutrition , came out of a review of previous studies that included more than 2500 individuals. Research has shown that low bone density, a predictor for osteoporosis, increases the risk of bone fracture. Epidemiologist and lead author Dr Tuan Nguyen, of Sydney's Garvan Institute of Medical Research Garvan Institute of Medical Research , says there are four main factors that influence bone density; genetics, hormones, exercise and nutrition. He expected vegans, those who avoid eating animal products, would have lower bone density and therefore a higher risk of bone fracture. The study found that on average vegans had a bone mass density 5% lower than non-vegans. But Nguyen says the study found vegans were no more likely to be treated for bone fractures than non-vegans. This is probably because vegans tend to be more health conscious, he says. "If you look at vegetarians as a whole they are certainly healthier, they tend to live longer and have lower risk of hypertension and heart disease." And there are other factors that may override the influence bone density has on fracture risk such as hormone deficiencies, smoking and lifestyle, says Nguyen.

Women at risk

The study also found women have lower bone densities and a higher risk of fracture. "About 70% of fractures in the elderly occur in women," says Nguyen. It's not clear why women have higher bone loss than men, but the common assumption is that the loss of oestrogen after menopause speeds up bone loss, he says. "We know oestrogen is very important in regulating bone formation and bone re-absorption." Nguyen suspects lower levels of calcium, needed for bone formation, in the diets of vegans results in lower bone density compared with non-vegans. But he admits overall calcium is only a small contributor to bone density.

Don't overdo diary

Nutritionist Dr Rosemary Stanton agrees with Nguyen saying that calcium is important but it is only one factor in bone density. "The push to have everyone eat massive amounts of dairy products is invalid," she says. Stanton says what's missing from the study is a differentiation between a good and bad vegan diet. "Just as you can have a good omnivorous diet and bad one, so too with vegan diets," she says. Stanton also says the study failed to consider the effects of vitamin D. "Vitamin D is probably the most important factor in the way calcium is used and studies are showing now that a lot of people don't get enough Vitamin D." Nguyen agress and suggests vegans monitor their calcium and vitamin D intake. Tags: exercise-and-fitness, diet-and-nutrition, diseases-and-disorders, older-people Email the editor ●Share this article ●Email a friend Use these social-bookmarking links to share Vegan diet leads to less dense bones.