March 28, 2005 -- Raw-food vegetarian diets are associated with osteoporosis, a new study shows.
Osteoporosis occurs when aging bone is broken down faster than it can be replaced, a process known as bone turnover. Doctors diagnose the bone-weakening disease with a bone mineral density test.
The study compared the bone health of 18 vegetarians who ate only raw foods with a similar group that ate a standard American diet. All participants were about 54 years old.
The vegetarians had been following this diet for 18 months to 10 years. Food diaries showed they ate various raw vegetables, fruits, nuts, seeds, sprouted grains, and cereals. They strictly avoided cooked, processed, or animal-based foods. That eliminated dairy products in their diet, a major source of calcium.
The researchers measured bone mineral density and also took blood and urine samples to measure bone turnover.
The study appears in the March 28 Archives of Internal Medicine.
Bad to the Bone
The vegetarians had a couple of strikes against them:
- Thinner. Their average body mass index (BMI) was 20, compared with 25 for their peers. Both are within normal BMI range, but thinness is a risk factor for osteoporosis.
- Lowered calcium and vitamin D in their diets. On average, the vegetarians ate about 580 milligrams of calcium per day, compared with 1,093 for their peers. Vitamin D from foods was also much lower in the vegetarians. Both nutrients are essential for building strong bone.
The raw-food vegetarians had low bone mineral densities, indicating osteoporosis. But their bone turnover rates were similar to the group that ate a standard American diet.
This was a surprise because thinner people are believed to have a faster bone turnover rate.
Since bone turnover was similar, what was causing their low bone mineral density?
What's Going On?
There aren't any definitive answers. The study was not designed to further explore this surprise finding, but the researchers say bone quality may be a factor.
"Although low bone mass is a risk factor for fracture, bone quality also plays a role," write the researchers. "It is therefore possible that raw foods vegetarians with a low bone mass may not have an increased incidence of fractures because of good bone quality."
Vegetarian or not, tips for avoiding osteoporosis include:
- Getting sufficient calcium. Recommendations for adults call for 1,000 milligrams per day up to age 50 and 1,200 milligrams per day after 50. Sources include dairy products, leafy greens, calcium-fortified products, and some nuts (like almonds). Supplements are also available.
- Getting enough vitamin D. Adequate intake in adults range from 200-600 international units per day.
- Strengthening bones through weight-bearing exercise. Walking, running, dancing, and lifting weights are a few of the options to help stimulate bone formation and improve bone health.
- Avoiding bone hazards. Avoid smoking and excess alcohol. Certain medications and the eating disorder anorexia can also raise the risk of osteoporosis.
- Taking medications, if recommended. Doctors may prescribe medications to treat or prevent osteoporosis.
- Get tested. A bone mineral density test can gauge the state of bone health. The scan is quick and painless; most health experts recommend it for women older than 65 or for younger people at risk of osteoporosis.