Gulffritallary
05-04-2004, 11:41 PM
Boning Up on Calcium
Aug 17, 2003 16:27 PDT
Are you getting enough? Too much?
The solution isn't as easy as gulping milk by the gallon or popping
supplements by the handful.
To call calcium the most hyped mineral in history would be an
understatement.There are dozens of heavily advertised supplements on
the market. On grocery store shelves, everything from orange juice to
bread is fortified with it.
Packages of antacids, such as Tums and Rolaids, brag about their calcium
content. And no one hypes the health benefits of calcium more than the
dairy industry.
All these products purport to help prevent osteoporosis, the
deterioration of bone mass due to calcium depletion, which afflicts
10 million Americans and causes 1.5 million fractures annually.
The specter of spending our senior years stooped over like a question
mark, slowly, carefully and painfully crossing the street with the
aid of a cane or a walker, afraid of sustaining a serious or even
fatal injury from a simple fall, is frightening indeed.
It would seem, therefore, that we should all eat as many calcium-rich
foods as possible and take calcium supplements to guard against this
debilitating condition, right?
Wrong!
At least, not without knowing what we are doing. Studies have
shown that those who ingest large quantities of calcium can also be
among the most at risk to develop osteoporosis.
The reason for this is that the amount of calcium we ingest does not
necessarily translate into the amount of calcium we absorb.
At least as important as the amount of calcium in our diet is the type
of calcium we eat, and what we eat with it.
Certain cofactors in proper proportion are absolutely necessary for the
body to absorb calcium, while other substances inhibit the body's
ability to do so.
The amount of gastric hydrochloric acid and the acidity (pH level) of
our bodies is also of fundamental importance.
Even our hormonal balance plays a key role in calcium metabolism.
Without taking all these factors into account, blithely loading up on
calcium can actually result in a net *deficiency* of the mineral.
The bones: our blood's *calcium bank*
Bone cells are the body's savings account of calcium.
When blood levels of calcium rise above normal,the excess is stored in
the bones.
Conversely, when calcium levels in the bloodstream dip, the body turns
to its bone bank to balance the deficit.
Our *serum* calcium level is affected by many factors, many of which
are not directly related to the amount of calcium in our diets.
For example, stress can reduce free calcium by disrupting hormone
balance.Stress stimulates the production of the hormone cortisol,
which in turn increases levels of the steroid hormone aldosterone, a
key regulator of mineral balance in the body.
Chronic stress can reduce blood calcium levels, requiring the body to
continually make withdrawals from the bone bank.
The dairy myth---
There is no question that we need an adequate dietary intake of
calcium. But how much is adequate? What are the best sources? And
what factors are necessary to absorb and utilize this calcium and to
maintain proper levels of calcium in both our bones and our
bloodstreams?
People equate calcium with dairy, and dairy products contribute 75%
of the calcium in American diets. Milk is a $19 billion industry in
the United States, and the Dairy Council spends hundreds of millions
of dollars in advertising and marketing every year. The Got Milk ad
campaign is among the most successful in advertising history.
However, scientists long have challenged the assumption that dairy
consumption equals strong bones. Now, thanks to new studies, their
argument is gaining momentum.
It's easy to understand why the dairy industry touts milk as the
perfect calcium conveyor.
An eight-ounce glass packs 300 mg of
calcium along with significant amounts of vitamins A and D, magnesium
and phosphorus all cofactors for bone health.
Cheese and yogurt are similarly endowed. But not everyone swallows the
idea that a diet chock-full of dairy is the best way to bank calcium.
The dairy industry's armor was badly pierced five years ago by a
Harvard Nurses' Health study published in the American Journal of
Public Health. Researchers examined the diets of 77,761 women during
a 12-year period.
What they found was that drinking milk did not protect the participants
against bone breaks. In fact, those who drank the most milk (three or
more glasses a day) had more fractures
than those who barely touched the stuff (less than one glass per
week).
I'm not surprised that people who consume a lot of dairy don't
necessarily have better bones, says Diane Feskanich, lead author of the
study and an epidemiologist at Brigham and Women's Hospital in Boston.
Feskanich is still monitoring the nurses to see how they're
faring, and she hopes to publish more data sometime this year. We
updated the analysis and found the same results: We don't see fewer
hip fractures with higher milk consumption, she says. There is
definitely a link between Dairy consumption and osteoporosis.
What the Nurses' Health study showed is that, as a preventative
strategy against osteoporosis, eating dairy products is no better
than a placebo, says Neal Barnard, M.D., president of the Physicians
Committee for Responsible Medicine, a nonprofit organization that
promotes vegetarianism and opposes milk consumption.
The dairy industry is built on convincing people that it works.
A more recent strike against the dairy industry came in the form of a
scientific review published last September in the American Journal of
Clinical Nutrition. Researchers at the University of Alabama gathered
all of the credible clinical evidence they could find on bone health and
dairy-rich diets.
After an exhaustive review of nearly five dozen studies, they concluded
that there is no solid body of evidence to
support eating dairy foods.
If dairy foods are so loaded with calcium, why are they not
protective of bones? One reason is dairy products' relatively high
protein and salt content.
The body utilizes calcium to metabolize both protein and salt.
Approximately 1 mg of calcium is needed to process 1 g of protein, and
Americans routinely eat 65 to 100 g or more of protein each day.
The authors of the study found that some dairy foods, such as cottage
and processed cheeses, are so high in protein and sodium, which also
acidifies the blood, that the combination could actually negate the
food's calcium benefits.
That discovery doesn't surprise Loren Cordain, Ph.D., an evolutionary
biologist at Colorado State University in Fort Collins. [See Cordain's
story, A Diet Solution Based on Evolution, March 2002.]
Cordain is one of a growing number of theorists who believe that the
crux of Americans' high rate of osteoporosis is not a lack of calcium
but our Western diet:
heavy on acid-inducing proteins and light on alkaline-enhancing fruits
and vegetables.
What we're seeing is a calcium imbalance, says Cordain. It's not about
how much comes in, it's about how much is *going out*.
Americans have the highest rates of osteoporosis-related fractures in
the world, yet we eat more dairy products than almost any other country.
The data sticks out like a sore thumb.
Indeed, the facts are confounding. People in North America and
northern European nations consume two to three times as much calcium
as their Asian counterparts, yet break two to three times as many
bones.
The United States has one of the world's highest recommended daily
allowances for calcium, and it keeps creeping higher.
According to the National Academy of Sciences, which sets the RDA, daily
calcium recommendations start at 1,300 mg for adolescents ages 9 to 18,
then lower to 1,000 mg for adults ages 19 to 50, and, finally, rise
again to 1,200 mg for people 51 and older.
Reaching the RDA for calcium is virtually impossible unless you're
eating tons of dairy products, which is precisely the point, says
Cordain.
Cordain likes to refer back to the diets of hunter-gatherers for
dietary guidance. He points out that milk is a recent phenomena and
that if what dairy advocates say is true, then everyone living before
the age of milk should have had osteoporosis.
We don't find that at all, he says. What we do find are robust,
fracture-resistant bones.
Holistic nutritionists also point out the unnatural aspect of what
was touted by the dairy industry as nature's most perfect food:
No other mammal drinks milk from its mother after it is weaned, and no
other species drinks the milk of another species.
Feskanich is also skeptical of the RDA for calcium. Upping the
calcium requirements doesn't seem to be helping prevent hip fractures in
America, she says. It's almost as though we keep raising it in hopes
that it will have some effect, and it just doesn't work.
So what does all this mean to someone who wants to eat a bone-healthy
diet? The science may be complicated, but the dietary advice is not.
Eat plenty of fruits and vegetables
If you find it hard to believe that eating green vegetables is a
superior way to get adequate calcium, consider the diet of dairy
cows.
These animals maintain their own huge bone structures and
produce calcium-rich milk from a diet of grass.
While it's true that, cup for cup, most vegetables have less calcium
than milk, the body is able to absorb more of the mineral when it comes
from a veggie source, explains Barnard, because it doesn't come packaged
with protein and refined salt.
In fact, the body absorbs more calcium from kale and broccoli than from
milk.
A 1997 study published in the New England Journal of Medicine found
that as participants upped their fruit and vegetable intake from 3.6
to 9.5 servings a day, their calcium loss declined 30%.
A minimum of five servings of fruits and vegetables a day is important
for bone health because it creates a more alkaline environment, and less
calcium is lost in the urine, Weaver says.
Among the richest sources of plant-based calcium are dark, leafy
greens, such as brussels sprouts, mustard greens, broccoli, turnip
greens and kale. But be aware: Not all calcium-rich veggies translate
that calcium into bone.
For example, spinach and sweet potatoes are loaded with calcium but are
reluctant to deposit it as they travel through the body; both are high
in oxalate and phytate, two compounds that inhibit calcium absorption.
(Cooking eliminates the oxalate problem.)
Don't depend on fortified foods -
When deciding where your calcium should come from, fortified foods
belong at the bottom of your list. The vitamins and minerals added to
processed foods are necessarily the cheapest available, and their
sources and forms are uncertain.
Foods that are artificially pumped full of calcium shouldn't replace
natural sources.
There are so many beneficial factors in food that haven't even been
identified; you really need to go to foods first, says dietician Lola
O'Rourke, a spokesperson for the American Dietetic Association.
Watch your salt intake-
A high-sodium diet drags calcium from bones to aid digestion.
Every day, the typical American eats 3 to 4 g of sodium, equaling a
daily calcium loss of up to 80 mg. By reducing your daily sodium intake
by 1 g, you'll save 1% of your skeletal mass each year.
Be sure to use natural sea salt
containing at least 2% trace minerals.
And do your best to avoid sinfully salty snacks, such as potato chips
and microwave popcorn. Give high-sodium, processed foods, such as frozen
dinners, the boot, too.
Trim protein
Eating just one meat-free meal a day can reduce your protein intake
by 40 g, meaning that 40 mg of calcium will stay in your bones, where it
belongs.
Plant-based proteins have the added advantage of
containing fiber, an adequate supply of which is essential for proper
digestive functioning.
Calcium is absorbed from the small intestine into the bloodstream, and
the health of the small intestine directly affects the amount of calcium
we absorb from our food.
Shun soda-
Last year, scientists at Harvard found that teens quaffing soft
drinks were three times more likely to break a bone than those who
didn't partake. The risk of injury jumped to five times more likely
for girl athletes.
Some researchers point to phosphoric acid as the
culprit since it's thought to hamper calcium absorption.
Get plenty of vitamin D-
Vitamin D must be present in sufficient quantity for your body to
absorb calcium from the intestines into the bloodstream. Be sure to
get outside and get adequate sunlight our bodies synthesize vitamin D
through the action of ultraviolet radiation on sterols (fat-like
substances) in the skin.
You can also add vitamin D-rich organic egg yolks
and fish oil to your diet.
For adults, the recommended daily allowance for vitamin D is 400 to 600
IU. Many seniors, especially
those who are housebound, suffer from a vitamin D deficiency. The
National Osteoporosis Foundation recommends up to 800 IU per day for
the elderly. Make sure you get your fill, but don't get carried away.
Exercise -
Bone density rises and falls according to the demands placed upon it, so
physical activity has lifelong implications for skeletal health.
Adults who were physically active during childhood have better bone
density than those who were couch potatoes. A recent study by
scientists at Pennsylvania State University found that exercise
during the crucial bone-building years is the best predictor of a
woman's adult bone health. Researchers tracked the diets and exercise
habits of 81 girls from age 12 to 18. Those girls who saw the greatest
bone gains as adults were those who exercised the most
during their teens, not those who consumed the most calcium.
So, boost your bone density by hitting the pavement or the gym.
Experts agree that 30 minutes of weight-bearing exercise, such as
walking or jogging, three times a week is all it takes to see
results. Strength training is also an excellent way to keep bones
strong. Either way, it is never too late to start.
In studies that examined physical activity among the elderly, exercise
reduced the risk of bone-breaking falls by 25%. Exercise gives your
bones a reason to live, says Barnard.
Check your stomach acidity
Calcium cannot be digested without sufficient stomach acid. It is
estimated that by age 50, most Americans have lost 50% of their acid-
producing stomach cells to protein overload, parasites, poisonous
substances in food and other factors.
Under the best of circumstances, only about 30% of the calcium we
ingest is absorbed; without sufficient hydrochloric acid in our
stomachs, this figure can drop as low as 4%.
This is also why antacids, which claim to be a
calcium source, actually work "against" calcium absorption.
Ironically, many people take these products because they suffer from
heartburn,
which they attribute to excess stomach acid.
Yet, according to gastroenterologist William Stuppy, M.D., the vast
majority of his
mature patients suffer from too little stomach acid, which can
produce the same "symptoms" as excess acid.
Dr. Stuppy warns especially against taking acid blockers such as Pepcid
AC.
For patients with chronic digestive problems, stomach pH can be
easily measured during routine tests. One more way to help your stomach
is to chew your food well: Food that is thoroughly masticated generally
requires less stomach acid to digest.
Supplement only with professional advice
When it comes to obtaining calcium from food, the options are
plentiful.
However, long-term calcium supplementation, particularly without the
other factors necessary for bone health, is not likely to stave off
osteoporosis. And without the advice of a qualified
holistic nutritionist or naturopathic doctor, it is possible to do
more harm than good.
The amount of bone-density increase you get from supplementation is
dubious, says Feskanich.
One theory is that it works initially and then plateaus. And there's the
issue of consuming too much.
Regularly ingesting calcium in excess of 2,000 mg a day may cause
constipation, kidney stones or other problems.
Michael Borkin, N.M.D., often puts his patients on a calcium
supplement or, more accurately, supplements.
He recommends rotating the form of calcium, however, between calcium
citrate (one of the easiest forms to absorb), calcium ascorbate and
calcium gluconate.
He also makes sure his patients supplement the necessary cofactors in
proper proportion, including vitamin D and phosphorus.
The relationship between calcium and magnesium is a good example of
the complexities of calcium supplementation. Magnesium has an inverse
relationship with calcium.
Both compete for the same receptor sites in cells, but a proper balance
of both is necessary for health.
The ratio can vary considerably from patient to patient.
The body can't absorb more than 500 mg of calcium at a time,
so supplements are best taken in small doses throughout the day.
Calcium can interfere with some medications, including antibiotics.
So if you're taking a prescription drug, consult your health-care
practitioner before adding a calcium supplement.
Contaminants, such as aluminum and lead, are also a concern with some
calcium supplements (such as Tums).
To find out if a supplement has aluminum, check the list of ingredients
on the label. (Tums Contains Aluminum)
Avoid supplements made with bone meal, dolomite or oyster shells, as
they often contain lead.
Remember, ingesting more calcium is not necessarily the key to
preventing osteoporosis. But getting the right calcium may be just
what your body needs.
Catherine Guthrie's health and medical writing has appeared in Self,
Yoga Journal, Health and on WebMD.
Men and calcium: A cautionary note
Calcium is usually talked about in connection with women and
osteoporosis (80% of osteoporosis sufferers are women), but more than a
dozen studies show a link between a high-calcium diet and prostate
cancer.
In one of the largest, scientists at the Harvard School of
Public Health studied the diets of 20,885 male physicians to tease
out the relationship between dairy products and prostate cancer risk.
Their results, published in the October 2001 issue of the American
Journal of Clinical Nutrition, found that men who consumed more than
600 mg of calcium per day had a 32% increased risk of prostate cancer
compared with those who took in less than 150 mg per day.
The authors concluded high calcium intake, mainly from dairy products,
may increase prostate cancer risk --
by lowering concentrations of 1,25-dihydroxyvitamin D3, a hormone
thought to protect against prostate cancer.
For each additional 500 mg of calcium from dairy products per
day, researchers saw a 16% jump in the men's prostate cancer risk.
There's a general message that the more calcium the better, says June
Chan, the study's lead author. That's not necessarily the case,
especially for men.
Even more surprising were results from a 1998 study that traced the
health of 50,000 men.
The researchers found that those men who were avid calcium consumers
(more than 2,000 mg per day) had a nearly
fourfold increase in the incidence of prostate cancer over their
calcium-shirking counterparts (500 mg or less a day).
Should men swear off calcium-rich foods? Chan says no. She suggests
that men are safe to stay within their RDA of 1,200 mg and can avoid
going overboard by taking a hard look at how much calcium they take
in daily,--
adding up the calcium they consume from dairy products,
fortified foods and multivitamins.
Don't forget to tally the calcium in antacids; Chan suspects that an
overdependence on the stomach-
soothers may be to blame for men's megadoses.
Other experts aren't so willing to rely on the RDA. Chan's advice is
flat out wrong, says Neal Barnard, M.D. He feels that medical
researchers, like Chan, are simply afraid to take a stand against the
dairy industry.
I understand that people hate to make a recommendation against a product
that we've known and loved, but enough is enough, says Barnard.
We can't cut the risk of prostate cancer to zero, but there are things
that help. I think men would be well-advised not to drink cow's milk.
Why We Need Calcium
There's no doubt that calcium is crucial to good health. It is the
most abundant mineral in our bodies, making up 1.5% to 2% of our
weight. Ninety-nine percent of this is stored in our bones and teeth;
our bones consist of about 70% calcium salts by weight. Calcium makes
our bones strong and rigid by forming part of the substance that cements
together the walls of adjacent cells.
But calcium does more than maintain our skeletal structure. It is
essential for the normal functioning of all body cells, acting as a
mediator for many vital cell functions.
While our bones contain 99%
of our calcium, the remaining 1% of free calcium circulating in our
soft tissues, bloodstream and extracellular fluid also performs some
crucial functions. For example, without calcium, blood will not clot.
Calcium also regulates muscles' contractility
and the beating of our heart. It regulates neurotransmitters at
synaptic junctions, where nerve impulses are passed from one neuron
to another, and calcium disregulation can cause mental and emotional
problems.
The body carefully regulates these calcium levels, keeping them
within the range of 50 to 65 mg per liter of extracellular fluid.
More or less than this can quickly lead to serious and even life-
threatening conditions.
Aug 17, 2003 16:27 PDT
Are you getting enough? Too much?
The solution isn't as easy as gulping milk by the gallon or popping
supplements by the handful.
To call calcium the most hyped mineral in history would be an
understatement.There are dozens of heavily advertised supplements on
the market. On grocery store shelves, everything from orange juice to
bread is fortified with it.
Packages of antacids, such as Tums and Rolaids, brag about their calcium
content. And no one hypes the health benefits of calcium more than the
dairy industry.
All these products purport to help prevent osteoporosis, the
deterioration of bone mass due to calcium depletion, which afflicts
10 million Americans and causes 1.5 million fractures annually.
The specter of spending our senior years stooped over like a question
mark, slowly, carefully and painfully crossing the street with the
aid of a cane or a walker, afraid of sustaining a serious or even
fatal injury from a simple fall, is frightening indeed.
It would seem, therefore, that we should all eat as many calcium-rich
foods as possible and take calcium supplements to guard against this
debilitating condition, right?
Wrong!
At least, not without knowing what we are doing. Studies have
shown that those who ingest large quantities of calcium can also be
among the most at risk to develop osteoporosis.
The reason for this is that the amount of calcium we ingest does not
necessarily translate into the amount of calcium we absorb.
At least as important as the amount of calcium in our diet is the type
of calcium we eat, and what we eat with it.
Certain cofactors in proper proportion are absolutely necessary for the
body to absorb calcium, while other substances inhibit the body's
ability to do so.
The amount of gastric hydrochloric acid and the acidity (pH level) of
our bodies is also of fundamental importance.
Even our hormonal balance plays a key role in calcium metabolism.
Without taking all these factors into account, blithely loading up on
calcium can actually result in a net *deficiency* of the mineral.
The bones: our blood's *calcium bank*
Bone cells are the body's savings account of calcium.
When blood levels of calcium rise above normal,the excess is stored in
the bones.
Conversely, when calcium levels in the bloodstream dip, the body turns
to its bone bank to balance the deficit.
Our *serum* calcium level is affected by many factors, many of which
are not directly related to the amount of calcium in our diets.
For example, stress can reduce free calcium by disrupting hormone
balance.Stress stimulates the production of the hormone cortisol,
which in turn increases levels of the steroid hormone aldosterone, a
key regulator of mineral balance in the body.
Chronic stress can reduce blood calcium levels, requiring the body to
continually make withdrawals from the bone bank.
The dairy myth---
There is no question that we need an adequate dietary intake of
calcium. But how much is adequate? What are the best sources? And
what factors are necessary to absorb and utilize this calcium and to
maintain proper levels of calcium in both our bones and our
bloodstreams?
People equate calcium with dairy, and dairy products contribute 75%
of the calcium in American diets. Milk is a $19 billion industry in
the United States, and the Dairy Council spends hundreds of millions
of dollars in advertising and marketing every year. The Got Milk ad
campaign is among the most successful in advertising history.
However, scientists long have challenged the assumption that dairy
consumption equals strong bones. Now, thanks to new studies, their
argument is gaining momentum.
It's easy to understand why the dairy industry touts milk as the
perfect calcium conveyor.
An eight-ounce glass packs 300 mg of
calcium along with significant amounts of vitamins A and D, magnesium
and phosphorus all cofactors for bone health.
Cheese and yogurt are similarly endowed. But not everyone swallows the
idea that a diet chock-full of dairy is the best way to bank calcium.
The dairy industry's armor was badly pierced five years ago by a
Harvard Nurses' Health study published in the American Journal of
Public Health. Researchers examined the diets of 77,761 women during
a 12-year period.
What they found was that drinking milk did not protect the participants
against bone breaks. In fact, those who drank the most milk (three or
more glasses a day) had more fractures
than those who barely touched the stuff (less than one glass per
week).
I'm not surprised that people who consume a lot of dairy don't
necessarily have better bones, says Diane Feskanich, lead author of the
study and an epidemiologist at Brigham and Women's Hospital in Boston.
Feskanich is still monitoring the nurses to see how they're
faring, and she hopes to publish more data sometime this year. We
updated the analysis and found the same results: We don't see fewer
hip fractures with higher milk consumption, she says. There is
definitely a link between Dairy consumption and osteoporosis.
What the Nurses' Health study showed is that, as a preventative
strategy against osteoporosis, eating dairy products is no better
than a placebo, says Neal Barnard, M.D., president of the Physicians
Committee for Responsible Medicine, a nonprofit organization that
promotes vegetarianism and opposes milk consumption.
The dairy industry is built on convincing people that it works.
A more recent strike against the dairy industry came in the form of a
scientific review published last September in the American Journal of
Clinical Nutrition. Researchers at the University of Alabama gathered
all of the credible clinical evidence they could find on bone health and
dairy-rich diets.
After an exhaustive review of nearly five dozen studies, they concluded
that there is no solid body of evidence to
support eating dairy foods.
If dairy foods are so loaded with calcium, why are they not
protective of bones? One reason is dairy products' relatively high
protein and salt content.
The body utilizes calcium to metabolize both protein and salt.
Approximately 1 mg of calcium is needed to process 1 g of protein, and
Americans routinely eat 65 to 100 g or more of protein each day.
The authors of the study found that some dairy foods, such as cottage
and processed cheeses, are so high in protein and sodium, which also
acidifies the blood, that the combination could actually negate the
food's calcium benefits.
That discovery doesn't surprise Loren Cordain, Ph.D., an evolutionary
biologist at Colorado State University in Fort Collins. [See Cordain's
story, A Diet Solution Based on Evolution, March 2002.]
Cordain is one of a growing number of theorists who believe that the
crux of Americans' high rate of osteoporosis is not a lack of calcium
but our Western diet:
heavy on acid-inducing proteins and light on alkaline-enhancing fruits
and vegetables.
What we're seeing is a calcium imbalance, says Cordain. It's not about
how much comes in, it's about how much is *going out*.
Americans have the highest rates of osteoporosis-related fractures in
the world, yet we eat more dairy products than almost any other country.
The data sticks out like a sore thumb.
Indeed, the facts are confounding. People in North America and
northern European nations consume two to three times as much calcium
as their Asian counterparts, yet break two to three times as many
bones.
The United States has one of the world's highest recommended daily
allowances for calcium, and it keeps creeping higher.
According to the National Academy of Sciences, which sets the RDA, daily
calcium recommendations start at 1,300 mg for adolescents ages 9 to 18,
then lower to 1,000 mg for adults ages 19 to 50, and, finally, rise
again to 1,200 mg for people 51 and older.
Reaching the RDA for calcium is virtually impossible unless you're
eating tons of dairy products, which is precisely the point, says
Cordain.
Cordain likes to refer back to the diets of hunter-gatherers for
dietary guidance. He points out that milk is a recent phenomena and
that if what dairy advocates say is true, then everyone living before
the age of milk should have had osteoporosis.
We don't find that at all, he says. What we do find are robust,
fracture-resistant bones.
Holistic nutritionists also point out the unnatural aspect of what
was touted by the dairy industry as nature's most perfect food:
No other mammal drinks milk from its mother after it is weaned, and no
other species drinks the milk of another species.
Feskanich is also skeptical of the RDA for calcium. Upping the
calcium requirements doesn't seem to be helping prevent hip fractures in
America, she says. It's almost as though we keep raising it in hopes
that it will have some effect, and it just doesn't work.
So what does all this mean to someone who wants to eat a bone-healthy
diet? The science may be complicated, but the dietary advice is not.
Eat plenty of fruits and vegetables
If you find it hard to believe that eating green vegetables is a
superior way to get adequate calcium, consider the diet of dairy
cows.
These animals maintain their own huge bone structures and
produce calcium-rich milk from a diet of grass.
While it's true that, cup for cup, most vegetables have less calcium
than milk, the body is able to absorb more of the mineral when it comes
from a veggie source, explains Barnard, because it doesn't come packaged
with protein and refined salt.
In fact, the body absorbs more calcium from kale and broccoli than from
milk.
A 1997 study published in the New England Journal of Medicine found
that as participants upped their fruit and vegetable intake from 3.6
to 9.5 servings a day, their calcium loss declined 30%.
A minimum of five servings of fruits and vegetables a day is important
for bone health because it creates a more alkaline environment, and less
calcium is lost in the urine, Weaver says.
Among the richest sources of plant-based calcium are dark, leafy
greens, such as brussels sprouts, mustard greens, broccoli, turnip
greens and kale. But be aware: Not all calcium-rich veggies translate
that calcium into bone.
For example, spinach and sweet potatoes are loaded with calcium but are
reluctant to deposit it as they travel through the body; both are high
in oxalate and phytate, two compounds that inhibit calcium absorption.
(Cooking eliminates the oxalate problem.)
Don't depend on fortified foods -
When deciding where your calcium should come from, fortified foods
belong at the bottom of your list. The vitamins and minerals added to
processed foods are necessarily the cheapest available, and their
sources and forms are uncertain.
Foods that are artificially pumped full of calcium shouldn't replace
natural sources.
There are so many beneficial factors in food that haven't even been
identified; you really need to go to foods first, says dietician Lola
O'Rourke, a spokesperson for the American Dietetic Association.
Watch your salt intake-
A high-sodium diet drags calcium from bones to aid digestion.
Every day, the typical American eats 3 to 4 g of sodium, equaling a
daily calcium loss of up to 80 mg. By reducing your daily sodium intake
by 1 g, you'll save 1% of your skeletal mass each year.
Be sure to use natural sea salt
containing at least 2% trace minerals.
And do your best to avoid sinfully salty snacks, such as potato chips
and microwave popcorn. Give high-sodium, processed foods, such as frozen
dinners, the boot, too.
Trim protein
Eating just one meat-free meal a day can reduce your protein intake
by 40 g, meaning that 40 mg of calcium will stay in your bones, where it
belongs.
Plant-based proteins have the added advantage of
containing fiber, an adequate supply of which is essential for proper
digestive functioning.
Calcium is absorbed from the small intestine into the bloodstream, and
the health of the small intestine directly affects the amount of calcium
we absorb from our food.
Shun soda-
Last year, scientists at Harvard found that teens quaffing soft
drinks were three times more likely to break a bone than those who
didn't partake. The risk of injury jumped to five times more likely
for girl athletes.
Some researchers point to phosphoric acid as the
culprit since it's thought to hamper calcium absorption.
Get plenty of vitamin D-
Vitamin D must be present in sufficient quantity for your body to
absorb calcium from the intestines into the bloodstream. Be sure to
get outside and get adequate sunlight our bodies synthesize vitamin D
through the action of ultraviolet radiation on sterols (fat-like
substances) in the skin.
You can also add vitamin D-rich organic egg yolks
and fish oil to your diet.
For adults, the recommended daily allowance for vitamin D is 400 to 600
IU. Many seniors, especially
those who are housebound, suffer from a vitamin D deficiency. The
National Osteoporosis Foundation recommends up to 800 IU per day for
the elderly. Make sure you get your fill, but don't get carried away.
Exercise -
Bone density rises and falls according to the demands placed upon it, so
physical activity has lifelong implications for skeletal health.
Adults who were physically active during childhood have better bone
density than those who were couch potatoes. A recent study by
scientists at Pennsylvania State University found that exercise
during the crucial bone-building years is the best predictor of a
woman's adult bone health. Researchers tracked the diets and exercise
habits of 81 girls from age 12 to 18. Those girls who saw the greatest
bone gains as adults were those who exercised the most
during their teens, not those who consumed the most calcium.
So, boost your bone density by hitting the pavement or the gym.
Experts agree that 30 minutes of weight-bearing exercise, such as
walking or jogging, three times a week is all it takes to see
results. Strength training is also an excellent way to keep bones
strong. Either way, it is never too late to start.
In studies that examined physical activity among the elderly, exercise
reduced the risk of bone-breaking falls by 25%. Exercise gives your
bones a reason to live, says Barnard.
Check your stomach acidity
Calcium cannot be digested without sufficient stomach acid. It is
estimated that by age 50, most Americans have lost 50% of their acid-
producing stomach cells to protein overload, parasites, poisonous
substances in food and other factors.
Under the best of circumstances, only about 30% of the calcium we
ingest is absorbed; without sufficient hydrochloric acid in our
stomachs, this figure can drop as low as 4%.
This is also why antacids, which claim to be a
calcium source, actually work "against" calcium absorption.
Ironically, many people take these products because they suffer from
heartburn,
which they attribute to excess stomach acid.
Yet, according to gastroenterologist William Stuppy, M.D., the vast
majority of his
mature patients suffer from too little stomach acid, which can
produce the same "symptoms" as excess acid.
Dr. Stuppy warns especially against taking acid blockers such as Pepcid
AC.
For patients with chronic digestive problems, stomach pH can be
easily measured during routine tests. One more way to help your stomach
is to chew your food well: Food that is thoroughly masticated generally
requires less stomach acid to digest.
Supplement only with professional advice
When it comes to obtaining calcium from food, the options are
plentiful.
However, long-term calcium supplementation, particularly without the
other factors necessary for bone health, is not likely to stave off
osteoporosis. And without the advice of a qualified
holistic nutritionist or naturopathic doctor, it is possible to do
more harm than good.
The amount of bone-density increase you get from supplementation is
dubious, says Feskanich.
One theory is that it works initially and then plateaus. And there's the
issue of consuming too much.
Regularly ingesting calcium in excess of 2,000 mg a day may cause
constipation, kidney stones or other problems.
Michael Borkin, N.M.D., often puts his patients on a calcium
supplement or, more accurately, supplements.
He recommends rotating the form of calcium, however, between calcium
citrate (one of the easiest forms to absorb), calcium ascorbate and
calcium gluconate.
He also makes sure his patients supplement the necessary cofactors in
proper proportion, including vitamin D and phosphorus.
The relationship between calcium and magnesium is a good example of
the complexities of calcium supplementation. Magnesium has an inverse
relationship with calcium.
Both compete for the same receptor sites in cells, but a proper balance
of both is necessary for health.
The ratio can vary considerably from patient to patient.
The body can't absorb more than 500 mg of calcium at a time,
so supplements are best taken in small doses throughout the day.
Calcium can interfere with some medications, including antibiotics.
So if you're taking a prescription drug, consult your health-care
practitioner before adding a calcium supplement.
Contaminants, such as aluminum and lead, are also a concern with some
calcium supplements (such as Tums).
To find out if a supplement has aluminum, check the list of ingredients
on the label. (Tums Contains Aluminum)
Avoid supplements made with bone meal, dolomite or oyster shells, as
they often contain lead.
Remember, ingesting more calcium is not necessarily the key to
preventing osteoporosis. But getting the right calcium may be just
what your body needs.
Catherine Guthrie's health and medical writing has appeared in Self,
Yoga Journal, Health and on WebMD.
Men and calcium: A cautionary note
Calcium is usually talked about in connection with women and
osteoporosis (80% of osteoporosis sufferers are women), but more than a
dozen studies show a link between a high-calcium diet and prostate
cancer.
In one of the largest, scientists at the Harvard School of
Public Health studied the diets of 20,885 male physicians to tease
out the relationship between dairy products and prostate cancer risk.
Their results, published in the October 2001 issue of the American
Journal of Clinical Nutrition, found that men who consumed more than
600 mg of calcium per day had a 32% increased risk of prostate cancer
compared with those who took in less than 150 mg per day.
The authors concluded high calcium intake, mainly from dairy products,
may increase prostate cancer risk --
by lowering concentrations of 1,25-dihydroxyvitamin D3, a hormone
thought to protect against prostate cancer.
For each additional 500 mg of calcium from dairy products per
day, researchers saw a 16% jump in the men's prostate cancer risk.
There's a general message that the more calcium the better, says June
Chan, the study's lead author. That's not necessarily the case,
especially for men.
Even more surprising were results from a 1998 study that traced the
health of 50,000 men.
The researchers found that those men who were avid calcium consumers
(more than 2,000 mg per day) had a nearly
fourfold increase in the incidence of prostate cancer over their
calcium-shirking counterparts (500 mg or less a day).
Should men swear off calcium-rich foods? Chan says no. She suggests
that men are safe to stay within their RDA of 1,200 mg and can avoid
going overboard by taking a hard look at how much calcium they take
in daily,--
adding up the calcium they consume from dairy products,
fortified foods and multivitamins.
Don't forget to tally the calcium in antacids; Chan suspects that an
overdependence on the stomach-
soothers may be to blame for men's megadoses.
Other experts aren't so willing to rely on the RDA. Chan's advice is
flat out wrong, says Neal Barnard, M.D. He feels that medical
researchers, like Chan, are simply afraid to take a stand against the
dairy industry.
I understand that people hate to make a recommendation against a product
that we've known and loved, but enough is enough, says Barnard.
We can't cut the risk of prostate cancer to zero, but there are things
that help. I think men would be well-advised not to drink cow's milk.
Why We Need Calcium
There's no doubt that calcium is crucial to good health. It is the
most abundant mineral in our bodies, making up 1.5% to 2% of our
weight. Ninety-nine percent of this is stored in our bones and teeth;
our bones consist of about 70% calcium salts by weight. Calcium makes
our bones strong and rigid by forming part of the substance that cements
together the walls of adjacent cells.
But calcium does more than maintain our skeletal structure. It is
essential for the normal functioning of all body cells, acting as a
mediator for many vital cell functions.
While our bones contain 99%
of our calcium, the remaining 1% of free calcium circulating in our
soft tissues, bloodstream and extracellular fluid also performs some
crucial functions. For example, without calcium, blood will not clot.
Calcium also regulates muscles' contractility
and the beating of our heart. It regulates neurotransmitters at
synaptic junctions, where nerve impulses are passed from one neuron
to another, and calcium disregulation can cause mental and emotional
problems.
The body carefully regulates these calcium levels, keeping them
within the range of 50 to 65 mg per liter of extracellular fluid.
More or less than this can quickly lead to serious and even life-
threatening conditions.