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|From: ||claudine (126.96.36.199)
|Subject: ||protein and calcium +vegans |
Date: || October 19, 2008 at 10:49 am PST|
In Reply to: Re: The Pros and Cons of Olive Oil? posted by Jeff Novick, MS, RD, LD, LN on October 19, 2008 at 9:45 am:
my drs. would disagree with you on low intakes of protein, calcium
my own experience not healing on this diet and now necessitating
more surgeries for my fracture 5 months later has me researching
the truth. i can post more but high protein is usually only needed
for healing fractures so i will just post on bone health related
for one calcium and vegans:
In February of 2007, the first study looking at vegan bone fracture
rates was released.14 The EPIC-Oxford study recruited 57,000
participants, including over 1,000 vegans and almost 10,000
lacto-ovo vegetarians (LOV), from 1993 to 2000. They were asked
to fill out a questionnaire to measure what they ate. About 5 years
after entering the study, they were sent a follow-up questionnaire
asking if they had suffered any bone fractures.
After adjusting for age alone, the vegans had a 37% higher fracture
rate than meat-eaters. After adjusting for age, smoking, alcohol
consumption, body mass, physical activity, marital status, and
births and hormone replacement therapy for women, the vegans
still had a 30% higher fracture rate. (Meat-eaters, fish-eaters, and
LOV fracture rates did not differ in any of the analyses performed.)
to read more on this from another study (sorry i am not allowed to
post links for some reason):
Hip Fracture Rates and Vegan Calcium Needs
Posted: July 23, 2001
Youíve written about calcium, protein, and bone health a number
of times and you always seem to stress that itís important for
vegans to get the RDA for calcium. Most of what Iíve read about
vegan diets shows that we donít need to worry about calcium. You
ignore the fact that, in cultures where people eat very low protein
diets, they donít have osteoporosis even though they have very low
calcium intakes. Since protein causes osteoporosis, and vegans eat
a low protein diet, vegans have low calcium needs.
Well, first of all, it is not actually a fact that people donít have
osteoporosis in those cultures. What is a fact is that we see a
smaller incidence of hip fractures in those cultures. And you are
right, I do ignore this, because it turns out that it is not especially
useful information for western vegans.
The idea that vegans do not need to worry about calcium is based
on the fact that, world wide, there is no relationship between the
incidence of hip fractures and intake of calcium. There does seem
to be a relationship between hip fractures and protein intake,
however, with hip fracture rates rising in countries where protein
intake is high (like the United States). There are also laboratory
studies showing that high protein intake negatively impacts bones.
As a result, many vegans believe that they have low calcium needs
because they have low protein intakes. But this is actually a very
simplistic interpretation of an extremely complex health issue.
Although Iíve written about the relationship between protein and
calcium before, I havenít written much about the hip fracture data,
so let me try to pull all of this information together here.
First, when we try to make comparisons of bone health in different
countries based strictly on rates of hip fractures, we are on rather
shaky ground. This is because, among different cultures, hip
fracture rates are affected by much more than diet. Here are some
of the factors that affect hip fractures:
0. Culture: The leading cause of a hip fracture is falling. That is, if
you have two people who both have osteoporosis, the one who
falls is the one who is going to break a hip. It is possible that
people fall more in some cultures than in others. For example, in
some Asian cultures, older people do not often go out by
themselves. They are part of an extended family and are often with
an adult child when they are away from home. This kind of support
would greatly reduce the risk of falling. People in these cultures
may also eat a lower protein diet. But if they simply fall less, how
can we say that their reduced hip fracture rate is related to their
diet rather than their lifestyle?
0. Geography: Again, this is related to falling. People who live in
warmer climatesĖwhere there is less snow and ice on the groundĖ
are less likely to slip and break a hip.
0. Genetics: This is especially important because it is less
speculative than the two factors I noted above. The hip bone in
Asians is shorter than in other groups and is more resistant to
breakage. This has nothing to do with diet and lifestyle; it is purely
a genetic factor. Also, some people, particularly those of African
background, metabolize calcium differently and have a genetic
predisposition to denser bones.
Itís easy to see that you canít look at hip fracture rates in different
cultures and make a conclusion about diet. There are too many
other factors at work here. So it shouldnít be too much of a
surprise to learn that, in some countries where hip fracture rates
are low, people still have considerable osteoporosis, in their spine
Therefore, it just is not possible to draw any conclusions about
bone health based on comparisons of hip fracture rates. It is also
impossible to determine vegan calcium needs based on these hip
Certainly, the relationship of protein to calcium is important. Diets
high in protein, particularly high in meat protein, can cause
excessive calcium losses. Protein increases the acidic condition of
the body, and the reaction in the body that neutralizes that acid
results in loss of calcium from bones. Itís normal to lose some
calcium since bones are dynamic and are always turning over. But
anything that raises the rate of calcium loss will also raise calcium
needs. But this is probably much less important when calcium
intake is high. Itís only when calcium intake is low that protein
appears to have an important effect on bone health. And it may
also be that it isnít so much the total amount of protein in your
diet that matters, but the ratio of protein to calcium. Vegans
actually have a ratio that is too high since, although their diets are
lower in protein, they are also often lower in calcium. (With the
growing number of calcium enriched foods for vegans on the
market, however, this may change).
Also, while too much protein may be harmful to bones, so is too
little protein. Studies show that among western women, protein is
linked to better bone health. And protein supplements have been
shown to speed healing of fractures. Although it isnít very difficult
to get adequate protein on a vegan diet, some vegan womenĖ
especially those who eat low calorie dietsĖmay have protein intakes
that are marginal.
In addition, there is some evidence that vegan women have lower
blood levels of estrogen. Since estrogen strengthens bones, these
lower levels may actually counter any positive effects of a more
moderate protein intake. Some vegans also have low levels of
vitamin D in their blood, which would increase risk for
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