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WASHINGTON
(Reuters) - People who adhere strictly to raw food vegetarian
diets are thin but have surprisingly robust bones, U.S. researchers
reported on Monday.
Although
nutritionists and the food industry have warned that a diet without
dairy foods can lead to the bone-thinning disease osteoporosis,
the team at Washington University School of Medicine in St. Louis
found the vegans they studied had many of the signs of strong
bones.
"We
think it's possible these people don't have increased risk of
fracture but that their low bone mass is related to the fact that
they are lighter because they take in fewer calories," Dr.
Luigi Fontana, who led the study, said in a statement.
"Raw
food vegetarians believe in eating only plant-derived foods that
have not been cooked, processed, or otherwise altered from their
natural state," Fontana's team wrote in this week's issue
of the Archives of Internal medicine.
"Because
of their low calorie and low protein intake, raw food vegetarians
have a low body mass index (BMI) and a low total body fat content.
It is well documented that a low BMI and weight loss are strongly
associated with low bone mass and increased fracture risk, while
obesity protects against osteoporosis."
Fontana's
team studied 18 strict raw food vegans aged 33 to 85. All ate
a diet that included unprepared foods such vegetables, fruits,
nuts, and sprouted grains. They had been on this diet for an average
of 3.6 years.
The
team compared them to 18 more average Americans. The raw food
group had an average body mass index of 20.5, while the average
group were slightly overweight with a BMI of 25.
BMI
is an internationally accepted measurement of height to weight,
and a BMI of 18.5 to 24 is considered the healthy range.
Fontana
expected the vegans to have low vitamin D levels because they
avoid all animal products including dairy. But in fact their vitamin
D levels were "markedly higher" than average.
Vitamin
D is made by the skin when the body is exposed to sunlight and
is key to keeping strong bones. It is added to milk and other
foods because it is so important.
"These
people are clever enough to expose themselves to sunlight to increase
their concentrations of vitamin D," Fontana said.
And
the vegans had low levels of C-reactive protein, an inflammatory
molecule that is becoming linked with the risk of heart disease,
diabetes and other chronic disease.
Furthermore,
they had lower levels of IGF-1, a growth factor linked to risk
of breast and prostate cancer.
Fontana
does not advocate a raw food diet. But he said that to lower the
risk of cancer and heart disease people should eat more fruits,
vegetables and whole grains.
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