Calcium

From: brian6@vaxb.mdx.ac.uk (Lightbulb joke collector extraordinaire and alt.fan.lightbulbs FAQ maintainer.)
Newsgroups: rec.food.veg
Subject: Calcium (all you ever wanted to know about...)
Date: 4 May 1995 07:57:14 GMT
Organization: Middlesex University, London, England
Lines: 457


CALCIUM
by Reed Mangels, Ph.D., R.D.

Summary: Calcium, needed for strong bones.
Green leafy vegetables such as kale are as good as or better than milk as
calcium sources. Other good sources include: White/Wholemeal bread, Taco
Shells, Oats, Soyabeans, Tofu, Almonds, Brazil Nuts, Pistachios, Sunflower
Seeds, Sesame Seeds, Flax Seed, Carob, Carrots, Cabbage, Garlic, Parsley
Spirulina, Chives, Seaweed, Cauliflower, Okra, Cassava, Figs, Papaya,
Rhubarb, Molasses, tap water...
High protein diets appear to lead to increased calcium losses. Calcium
requirements for those on lower protein, plant-based diets are
believed to be below the usual recommendations.
The [American] National Research Council itself (which set the RDA values
in the first place), acknowledges that people have been able to maintain
calcium balance on intakes of as low as 200 - 400 gm/day. They recommended
the 800 mg/day because of the excessively HIGH PROTEIN diet of most
Americans (see NRC, RECOMMENDED DIETARY ALLOWANCES, 9TH ed., 1980, p. 120-29)

Calcium is a very important mineral in the human body. Our
bones contain large amounts of calcium which helps to make them
firm and rigid. Calcium is also needed for many other tasks
including nerve and muscle function and blood clotting. These
other tasks are so important for survival, that, when dietary
calcium is too low, calcium will be lost from bone and used for
other critical functions. Calcium in the blood is tightly controlled
by the body, so calcium status cannot be assessed by measuring
blood calcium levels.

Because of heavy promotion by the American dairy industry, the
public often believes that cow's milk is the sole source of calcium.
However, other excellent sources of calcium exist so that vegans
eating varied diets need not be concerned about getting adequate
calcium. Table 9 (see below) shows the amount of calcium in
selected foods. When you realize that there is as much calcium in
5 ounces of firm tofu or 3/4 cups of collard greens as there is in
one cup of cow's milk, it is easy to see why groups of people who
do not drink cow's milk still have strong bones and teeth.

How much calcium do we need? The RDA for adults age 25 and
older is 800 milligrams of calcium per day (1). An intake of 1200
milligrams of calcium per day is recommended for those age 11-24.
In other countries, calcium recommendations are lower than in the
US. For example, British adults are advised to have a calcium intake
of 500 milligrams per day (2) and adults in Japan are told to have 600
milligrams of calcium daily (3). Does only science influence these
recommendations or are political and economic factors also at work?
(Read Nutrition Action Health Letter from Center for Science in the
Public Interest, Vegetarian Journal, Guide to Healthy Eating from
Physician's Committee for Responsible Medicine, Nutrition Week
from the Community Nutrition Institute, Advertising Age, and
National Dairy Council materials for insight into forces shaping
recommendations.)

Calcium requirements may be influenced by high protein intakes (4).
High protein diets seem to markedly increase the amount of calcium
lost from the body every day (5,6). In fact, when young adults had a
protein intake of 48 grams per day (slightly lower than the current
RDA) they had no net loss of calcium, even though the amount of
calcium in their diet was as low as 500 milligrams daily (7). In
contrast, when young adults were on a diet high in protein (112 grams
-- typical of many Americans), they lost substantial amounts of
calcium in their urine, even when calcium intakes were as high as
1400 milligrams per day (7).

Although phosphorus, another mineral found in foods which are high
in protein, does reduce the effects of protein on calcium somewhat,
calcium status appears to be more affected by the amount of protein
in the diet (5, 6). A protein intake above 70 grams per day is not
recommended (6). Of course, this level of protein intake is likely to
be exceeded on a meat-based diet or a diet high in dairy products. As
Table 10 (see below) shows, by eating 2 servings of meat or fish, an
egg, and 2 cups of milk every day, a person would come close to
exceeding the 70 gram upper limit for protein without even
considering other protein sources such as breads and vegetables.

____________________________

Table 9: Calcium Content of Selected Vegan Foods

Food Amount Calcium (mg)
____________________________________________________________________

Tofu, firm, processed
with calcium 4 ounces 250-765
sulfate*
Tofu, regular, processed
with calcium 4 ounces 120-392
sulfate*
Collard greens, cooked 1 cup 357
Rhubarb, cooked 1 cup 348
Spinach, cooked 1 cup 278
Blackstrap molasses 2 TB 274
Turnip greens, cooked 1 cup 249
Tofu, firm, processed
with nigari* 4 ounces 80-230
Kale, cooked 1 cup 179
Sesame seeds 2 TB 176
Okra, cooked 1 cup 176
Soybeans, cooked 1 cup 175
Beet greens, cooked 1 cup 165
Bok choy, cooked 1 cup 158
Tempeh 1 cup 154
Mustard greens, cooked 1 cup 150
Figs, dried or fresh 5 medium 135
Tahini 2 TB 128
Tofu, regular, processed
with nigari* 4 ounces 80-146
Swiss chard, cooked 1 cup 102
Almonds 1/4 cup 97
Broccoli, cooked 1 cup 94
Almond butter 2 TB 86
Soymilk, commercial, plain 8 ounces 84

*Read the label on your tofu container to see if it is
processed with calcium sulfate or nigari.

The RDA for calcium for adults, 25 and older, is 800 milligrams per
day; for those 11-24, the RDA is 1200 milligrams of calcium. United
States recommendations are more than 50% higher than the British
and Japanese.

Note: Oxalic acid, which is found in spinach, rhubarb, chard, and
beet greens is often said to bind with calcium and reduce absorbtion.
In laboratory experiments, calcium does combine with oxalates. However,
at normal dietary intakes, oxalates have little practical effect on
calcium absorbtion (1).

Sources: Composition of Foods. USDA Handbook 8.
Manufacturer's information.
______________________________________________________________________

The type of protein may also be important. At least one study shows
that soy protein, even at high levels, does not increase calcium
excretion the same way that protein from animal sources does (5).

The RDAs for calcium were made for people consuming typical
American high protein diets. Many vegan diets are lower in protein
than these typical American diets. For those whose protein intake is
lower, but adequate, or whose protein is from non-animal sources,
calcium intakes below the RDA are probably adequate.

We recommend that two or more servings of good sources of dietary
calcium be eaten daily by adults, along with the use of a diet without
excessive protein. Teenagers and young adults (age 20-25) should eat
3 or more servings of foods high in calcium. Regular weight-bearing
exercise such as walking, running, or aerobic dance is also
recommended to promote strong, healthy bones.

Vegetarian, and especially vegan, diets are often high in fiber due to
frequent use of whole grains, beans, fruits, and vegetables. This may
be one reason why vegetarians have a lower incidence of heart
disease and some kinds of cancer than does the general public.
However, one concern with diets high in fiber is that the fiber can
bind with minerals, like calcium, in the intestine and thus keep the
minerals from being absorbed. Vegan diets may contain 40 or more
grams of fiber per day (8). Dietary fiber intakes of 35 grams or less
are not believed to have a significant impact on mineral absorption
(9). However, humans may be able to adapt to diets with more than
35 grams of dietary fiber, so that, in time, these diets have little effect
on calcium absorption. This adaptation apparently occurs in vegans
since bone density of vegans appears to be normal (10). If calcium
absorption was impaired, bone density of vegans would be expected
to be low.

What about osteoporosis? Don't vegans need extra calcium to
prevent osteoporosis? In osteoporosis, bones become porous and
fragile. The Dairy Council leads us to believe that milk is essential
to prevent osteoporosis. In reality, many other foods besides milk (see
Table 9, above) provide calcium, often without the high dose of
protein seen in milk.

Other factors which increase the risk of osteoporosis include small
frame size, female sex, aging, heredity, cigarette smoking, excessive
alcohol, Caucasian or Oriental race, steroid use, early menopause, and
prolonged immobilization.

The most promising way that nutrition can reduce the risk of
osteoporosis is by promoting development of a favorable peak bone
mass during the first 3 to 4 decades of life. Several studies have
shown that vegetarians have the same (11, 12) or larger (13) bone
masses than do omnivores.


References

1. Food and Nutrition Board, National Research Council:
Recommended Dietary Allowances, 10th ed. Washington, DC:
National Academy Press, 1989.

2. Department of Health and Social Security: Recommended
Daily Amounts of Food Energy and Nutrients for Groups of People
in the United Kingdom. London: HMSO, 1979.

3. Recommended Dietary Allowances for Japan. Tokyo, Japan:
Ministry of Health and Welfare, 1984.

4. Food and Nutrition Board, National Research Council:
Recommended Dietary Allowances, 9th ed. Washington, DC:
National Academy Press, 1980.

5. Zemel MB: Calcium utilization: Effect of varying level and
source of dietary protein. Am J Clin Nutr 48: 880-883, 1988.

6. Kerstetter JE and Allen LH: Dietary protein increases urinary
calcium. J Nutr 120: 134-136, 1990.

7. Linkswiler HM, Zemel MB, Hegsted M, Schuette S:
Protein-induced hypercalciuria. Fed Proc 40: 2429-2433, 1981.

8. Roe LS, Thorogood M, Mann JI: Diet and plasma lipids in a group
of vegetarians and omnivores. Proc Nutr Soc 49: 59A, 1990.

9. Kelsay JL: Update on fiber and mineral availability. In Vahouny
GW and Kritchevsky D (eds): Dietary Fiber. New York: Plenum
Publishing Corporation, 1986; 361-372.

10. Ellis FR et al: Incidence of osteoporosis in vegetarians and
omnivores. Am J Clin Nutr 25: 555-558, 1972.

11. Hunt IF, Murphy NJ, Henderson C et al: Bone mineral content
in postmenopausal women: comparison of omnivores and
vegetarians. Am J Clin Nutr 50: 517-523, 1989.

12. Marsh AG, Sanchez TV, Chaffee FL et al: Bone mineral mass
in adult lacto-ovo-vegetarian and omnivorous males. Am J Clin Nutr
37: 453-456, 1983.

13. Marsh AG, Sanchez TV, Mickelsen O et al: Cortical bone
density of adult lacto-ovo-vegetarian and omnivorous women. J Am
Diet Assoc 76: 148-151, 1980.


This article was originally published in _Simply Vegan_, published by:

The Vegetarian Resource Group / Vegetarian Journal
P.O. Box 1463
Baltimore, MD 21203
(410) 366-VEGE

For questions or comments on this article, please contact Brad Scott at
brad@clark.net. This article is copied with the permission of the authors.
Copyright 1991 by Debra Wasserman and Reed Mangels, Ph.D., R.D.

______________________________________________________________________


And here's the Physicians
Committee for Responsible Medicine (PCRM) position paper on calcium. Good
sources of calcium are included in and at the end of the article.


BONING UP ON CALCIUM AND OSTEOPOROSIS

It is a common myth that people should increase their calcium intake.
Mostly, they are encouraged to take supplements and to drink more milk. But
milk may not "do a body good." The highest rates of osteoporosis are in the
industrialized Western nations~the biggest consumers of milk. It turns out
that keeping strong bones depends more on preventing calcium loss than on
increasing calcium intake.

Calcium in the Body: Almost all of the calcium in the body is in the
bones. There is a tiny amount in the blood stream which is responsible for
muscle contraction, maintenance of the heartbeat, and transmission of nerve
impulses and other functions. Hormones control the amount of calcium in the
blood. Everyone constantly loses calcium through urine, sweat, and feces,
and it is renewed with calcium from the bones. In the process, the body
constantly breaks down and rebuilds bones. Ultimately, the body's calcium
is replaced by calcium from food.

Reducing Calcium Loss: Since the 1920's researchers have known that diets
that are high in protein, especially animal protein, cause calcium to be
lost through the urine[1]. In nations with high rates of osteoporosis,
protein intake is generally high~usually more than twice the U.S.
Recommended Daily Allowance. Vegetarians have lower rates of osteoporosis
than meat eaters. This may be due to the lower protein intake of
vegetarians. Different types of protein also affect this loss. Meats are
overly high in protein and are high in a particular kind of protein
building block, called sulfur-containing amino acids. These cause increased
calcium loss[2]. Caffeine and sodium also increase the rate at which
calcium is lost through urine. Alcohol inhibits calcium absorption and may
also be toxic to bone[3]. Vitamin D, copper, zinc, manganese, fluorine, and
boron are all essential for good bone formation, and weight-bearing
exercise also increases bone mass and helps to prevent osteoporosis[4].
Boron appears to help stop the loss of calcium. The best way to get boron
is through fruits, vegetables, and beans.

The Need for Calcium: Throughout life, people's calcium needs change.
Until about age 35, people consume more calcium that their bodies lose. But
around age 45, the body begins to slip into "negative calcium
balance"~slowly the body loses more calcium than it takes in. As shown
above, how rapidly calcium is lost depends, in part, on how much protein is
in the diet, and the kind of protein it is. The loss of too much calcium
can lead to "soft bones," or osteoporosis.

Fighting Bone Loss: Most studies have shown that high doses of calcium do
not slow bone loss. In fact, many populations with high intakes of calcium
also have high rates of osteoporosis[5], probably because their high
protein intake causes significant calcium loss. Some African cultures
consume no dairy products and typically get only 175 to 475 milligrams of
calcium per day (800mg is the U.S. RDA), but they have low rates of
osteoporosis. Rates of hip racture among different populations is one way
researchers measure the prevalence of osteoporosis. One such study of ten
nations revealed that as calcium intake increased, so did the number of hip
fractures. Such studies have also led researchers to believe that exercise
and other factors have more to do with preventing osteoporosis than calcium
intake does.

Absorbing Calcium: The body carefully regulates its calcium absorption.
The average person absorbs 30 to 70 percent of the calcium she or he eats,
but the more calcium taken in, the less the body will absorb. This is to
protect the body from overdosing on calcium. At the U.S. RDA of 800mg, the
body may absorb as little as 15 percent of the total amount. This may be
one reason that high calcium intake does not generally prevent bone loss.
While milk is a source of calcium, it certainly is not the ideal way
to get your daily dose. Dairy products, with the exception of skim
products, are loaded with saturated fat. Fat is directly related to heart
disease and cancer. Dairy products are also high in protein. There are
other reasons to worry about milk, too. Cows are routinely fed antibiotics.
These are then passed directly on to the milk drinkers; antibiotics are
detectable in one out of three cartons of milk. Many people are also
allergic to milk, and over three-fourths of the world's population is
lactose-intolerant, which means their bodies lack the enzymes necessary to
digest milk.

Great Sources of Calcium: Dark green vegetables, such as broccoli and
collard, mustard, and turnip greens are much better sources of calcium than
milk. A single cup of broccoli contains almost a fourth of the U.S. RDA of
calcium. Another good source is calcium-fortified orange juice. Beans and
tortillas are also good sources of calcium.
Some people do need hormone treatments and/or calcium supplementation
for varying conditions. The risks and benefits should be discussed with
one's doctor.

Conclusion: Calcium is an essential nutrient and is needed for healthy
bones particularly during childhood and adolescence. While it is uncertain
how much calcium is actually needed, it is certain that diet affects
calcium balance. Calcium supplements are not the best way to control
osteoporosis for most people. A diet that is modest in protein,
complemented by exercise, is much more effective. Green leafy vegetables
and beans are good sources of calcium that are also moderate in protein and
very low in fat.

References:

1. Hegsted M, Schuette SA, et al. Urinary calcium and calcium balance in
young men as affected by level of protein and phosphorus intake. J Nutr
1981;111:553-562.
2. Marsh AG, Sanchez TV, et al. Cortical bone density of adult lacto-ovo-
vegetarian and omnivorous women. J Am Diet Asso 1980;76:148-150.
3. Rivlin, RS. Women's health: osteoporosis. Public Health Reports
1986;131-135.
4. Schaafsman F, van Beresteyn ECH, et al. Nutritional aspects of
osteoporosis. Wld Rev Nutr Diet 1987;49:121-159.
5. Hegsted DM. Calcium and Osteoporosis. J Nutr 1986;116:2316-2319.


CALCIUM SOURCES

Calcium is found in a variety of plant foods. The following are low-fat,
cholesterol-free sources of calcium.

Food Amount Milligrams of Calcium
Collard Greens 1 cup 355 mg
Bok Choy 1 cup 250 mg
Turnip Greens 1 cup 200 mg
Kale 1 cup 200 mg
Broccoli 1 cup 180 mg
Kelp (Seaweed) + cup 170 mg
Mustard Greens 1 cup 150 mg
Wakame (Seaweed) + cup 150 mg
Blackstrap Molasses 1 Tbsp 140 mg
Amaranth + cup 140 mg
Great Northern Beans 1 cup 140 mg
Dried Figs 5 figs 135 mg
Vegetarian Baked Beans 1 cup 130 mg
Navy Beans 1 cup 130 mg
Corn Tortilla 1 tortilla 120 mg
Fortified Orange Juice 6 ounces 120 mg
Kidney Beans 1 cup 115 mg
Black Beans 1 cup 105 mg
Okra 1 cup 90 mg
Acorn Squash 1 cup 90 mg
Pinto Beans 1 cup 85 mg
Tofu + cup 130 mg
Soybeans 1 cup 175 mg


Physicians Committee for Responsible Medicine, P.O. Box 6322, Washington,
DC 20015, USA, Telephone: 202 686-2210

************end of article************

And finally, extracts from
1993 POSITION OF THE AMERICAN DIETETIC ASSOCIATION: VEGETARIAN DIETS

Authors:
Suzanne Havala, MS, RD
Johanna Dwyer, DSc, RD

Reviewers:
Phyllis Acosta, RD
Patricia Johnston, DrPH, RD
Mary Clifford, RD; Vegetarian Nutrition dietetic practice group
Winston Craig, PhD, RD
Virginia Messina, MPH, RD; Pediatric Nutrition dietetic practice group

Reprinted from the Journal of the American Dietetic Association,
November 1993, Volume 93, Number 11.


A considerable body of scientific data suggests positive relationships
between vegetarian diets and risk reduction for several chronic
degenerative diseases and conditions, including obesity, coronary artery
disease, hypertension, diabetes mellitus, and some types of cancer.


POSITION STATEMENT

It is the position of The American Dietetic Association that vegetarian
diets are healthful and nutritionally adequate when appropriately
planned.


Certain plant constituents appear to inhibit the absorption of dietary
calcium, but within the context of the total diet, this effect does not
appear to be significant. Calcium from low-oxalate vegetable greens,
such as kale, has been shown to be absorbed as well or better than
calcium from cow's milk (15). Calcium deficiency in vegetarians is rare,
and there is little evidence to show that calcium intakes below the
Recommended Dietary Allowance (13) cause major health problems in the
vegetarian population. The relatively high US recommendations for
calcium intake, compared with those for populations consuming a more
plant based diet, are designed to compensate for the calciuric effect of
high intakes of animal protein, which are customary in the United
States. Studies have shown that vegetarians, on the other hand, absorb
and retain more calcium from foods than do nonvegetarians (16,17).


References


13. Food and Nutrition Board. Recommended Dietary Allowances. 10th ed.
Washington, DC: National Academy Press; 1989.

15. Heaney R, Weaver C. Calcium absorption from kale. Am J Clin Nutr.
1990;51:656.

16. Zemel M. Calcium utilization: effect of varying level and source of
dietary protein. Am J Clin Nutr. 1988;48:880.

17. Marsh A, Sanchez T, Michelsen O, Chaffee F, Fagal S. Vegetarian
lifestyle and bone mineral density. Am J Clin Nutr. 1988;48:837-841.

* ADA Position adopted by the House of Delegates on October 18, 1987,
and reaffirmed on September 12, 1992. The update will be in effect until
October 1997.
Originally Posted by Skylinux @ 2006-05-21 22:16:44

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