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People who follow a raw food vegetarian diet are
light in weight but healthy, according to US researchers.
It has been suggested that eating only plant-derived foods that have
not been cooked or processed might make bones thinner and prone to
fractures.
But a study in Archives of Internal Medicine found although bones were
lighter on this diet, turnover rates were normal with no osteoporosis.
The lower bone mass is down to raw food eaters being slim, believe the
authors.
The researchers compared the bone health of 18 people who had been
following strict raw food diets for up to 10 years with that of people
who ate a more typical American diet, including refined carbohydrates,
animal products and cooked foods.
The raw food diet is different to more typical vegetarian and vegan
diets, which do not exclude cooked, processed or otherwise refined
foods.
The groups were matched according to age, sex and socioeconomic
status.
To gauge bone health, the researchers looked at each person's body
weight, bone weight and mineral density, markers of bone turnover,
levels of vitamin D and inflammatory markers.
Bone health
The raw food vegetarians in the study had lower body weights (BMI) and
total body fat than the other volunteers. They also had lower bone
mass and bone mineral density.
"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," said the researchers.
But the people who followed raw food diets did not have any other
biological markers that typically accompany osteoporosis and had
normal rates of bone turnover.
Lead researcher Dr Luigi Fontana, from Washington University School of
Medicine in St Louis, said: "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 Fontana said the raw food diet group also had higher vitamin D
levels than people on a typical Western diet, even though they did not
consume dairy products which are known to be a good source of vitamin
D.
He said this was probably down to sun exposure.
Dr Stephen Walsh, nutrition spokesperson for the Vegan Society, said
it was to be expected that people who ate only raw foods would be
slimmer and that this would in turn have an effect on bone mass.
Balanced diet
He stressed that raw food vegetarians account for only a minority of
people who are vegan and vegetarian, and that some might find it
difficult to get enough calories to maintain a healthy weight eating
only raw foods.
"We recommend a varied, healthy, balanced diet which includes raw
fruit and vegetables as well as other foods," he said.
A spokeswoman from the Vegetarian Society said the study was
interesting, but given that only 18 people were studied, its
usefulness to those wishing to follow a vegetarian or vegan diet was
very limited.
"We recommend eating a healthy, well balanced vegetarian or vegan diet
that includes 2-3 portions per day of high protein foods such as
pulses, nuts, soya and wheat proteins, five portions of carbohydrates
(the less refined the better), 2-3 portions of dairy products or
calcium-enriched dairy alternatives and at least five portions of
fruit and vegetables.
"Raw foods can and should be included within this 'balance' but it is
not advisable to embark on an exclusively raw food diet without proper
research and expert advice," she said.
A spokesman for the National Osteoporosis Society said: "This is an
interesting study which highlights the fact that low bone density is
just one part of our overall risk of breaking bones.
"We would recommend that raw food vegans make sensible food choices to
ensure they are taking in an adequate amount of calcium from a variety
of foods and ensure they obtain good amounts of vitamin D from
sensible exposure to sunlight."
Elaine Bruce, experienced naturopath, homeopath and director of the UK
Centre for Living Foods, said calcium was important for building
bones, but that inorganic calcium in the form of supplements would not
do the job.
"You have to have organic calcium as it occurs in fresh green leafy
vegetables. "What we do in our programme is maximise that intake by
having it in juice form."
She said that the chlorophyll found in green plants and vegetables
also contained right amount of magnesium that is essential for the
uptake of calcium for healthy bones.
"The chemical composition of chlorophyll and blood is very similar
which further facilitates this uptake," she added.
© BBC MMV
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