Hi Jean Louis and Alan,

I wanted to add a few thoughts to the discussion on calcium.

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Copyright 1999, by LIFEF0RCE, Inc.; all rights reserved.

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In my opinion, in a a discussion of calcium needs there are four questions
that need to be considered:

1. How much do we need?
2. What are the best sources for calcium?
3. What other factors need to be considered for optimal absorption?
4. What are the risks associated with deficiency or excess calcium?


1. HOW MUCH DO WE NEED?

On this first point, the answer is complex, because calcium requirements
vary widely throughout an individual's lifetime, as well as from one
individual to another. Infants, children, adolescents, adults, and the
elderly all
have very different calcium requirements, as do females and males, and
pregnant or nursing mothers. General guidelines are: infants (to 6 months)
400 mg
daily; 6-12 months 600 mg; 1-5 years 800 mg; 6-10 years 800-1,200 mg; 12 -
24 years 1,200-1,500 mg; women 25-50 years 1,000 mg; pregnant or nursing
women 1,200-1,500 mg; post-menopausal women 1,500 mg; men 25-65 years 1,000
mg; and all men and women over 65 1,500 mg. These, of course, are GENERAL
guidelines, and again, vary widely from one individual to another, based on
the factors discussed below.



2. WHAT ARE THE BEST SOURCES FOR CALCIUM?

This is also a difficult question, and a critical one. Dairy products, in
my opinion, represent a very reliable source of calcium, because of their
high calcium content. Goat's or sheep's milk might be a better choice for
those who cannot tolerate either cow's milk protein or sugar. Solid dairy
products, such as some cheeses, might be another low lactose alternative;
or fermented products like kefir or yogurt. The green vegetables that have
been mentioned by Jean Louis are good sources of calcium, also tofu set in
calcium, mackerel, herring, sardines, and the nuts previously mentioned,
all are high in calcium.

Supplements are an option for people who for whatever reasons cannot get
calcium through their diet. But taking supplements is tricky, too.
Supplements need to be prepared in such a way that they are not vulnerable
to the digestive acids; however to confuse matters, there is one form,
calcium carbonate, which cannot be absorbed by people who do not produce
enough gastric acid (a common occurence on our "modern" diet. In addition,
both because calcium supplements can interfere with iron absorption, and
because there are food elements which can interfere with the absorption of
the supplements themselves (oxalates and phytates), supplements should not
be
taken with meals. Furthermore, side effects, in the form of heartburn,
acidy stomach, and constipation, can occur with supplementation. Finally,
supplements derived from either dolomite or bone-meal (both "natural"
products found widely in health food stores) should never be used, since
they often contain lead and other heavy metals.


3. WHAT OTHER FACTORS SHOULD AFFECT CALCIUM ABSORPTION?

i) In addition to dietary intake, MANY other factors influence calcium
absorption by the body. Other _dietary_ factors have a huge impact on
whether or not adequate calcium is absorbed, the most significant of these
probably
being whether or not there is adequate Vitamin D intake (or synthesis
through exposure to sunlight). This is a big problem in the darker, more
northern climates (particularly if the traditional "compensatory" diet is
discarded
for a more "civilized" one, thereby excluding all the traditional vitamin-D
rich cold-water fatty fish consumed in many forms), as well as with the
house-bound, or elderly, or infirm. Without Vitamin D, less than 10 percent
of calcium can be absorbed through diet.

ii) Aluminum from "Tums" or other antacids is associated with excessive
urinary excretion of calcium, and bone resorption.

iii) Hormonal balance is also a critical factor in the absorption of
calcium. Chronically high insulin levels (hyperinsulinemia) can reduce
absorption of
calcium by as much as 80 percent. Levels of estrogen, growth hormone, IGF1,
and paraththyroid hormone, all have a significant impact on calcium
balance.

iv) Drugs, age, ethnic and genetic heritage, a wide myriad of
gastrointestinal
disorders (such as leaky gut syndrome, liver or renal disturbances) all
have a critical impact on the absorption or excretion of calcium. Lack of
physical excercise is a critical factor - the rate of bone loss has been
shown to be _extremely_ rapid in individuals who remain entirely sedentary.

v) Calcium balance is influenced not only by intestinal absorption, but by
factors that influence urinary excretion, or fecal loss of calcium. In
fact, loss of calcium through the urine or stool accounts for 50 percent of
the variance in calcium balance, as opposed to only 25 percent due to
dietary intake or problems of absorption. The "SAD" diet typically contains
high levels of salt, and of certain forms of animal protein, factors which
are often cited (and hotly debated) as important in influencing high
calcium excretion.


4. CALCIUM DEFICIENCY AND EXCESS

The body provides an adaptive mechanism for insuring that calcium
balance remains stable, in which absorption _decreases_ as intake
_increases_. However, this mechanism is effective only up to a certain
point (about 3.5
grams per day), and beyond that point the body becomes unable to handle the
overload, and will become toxic. High blood levels cause "milk alkali
syndrome" (ectopic calcium deposition, or calcium toxicity), and severe
kidney damage. This is a problem frequently seen as a result of the overuse
of "Tums" (and other over-the-counter antacids).

As mentioned before, excess calcium intake can interfere with the
absorption of iron, so this can be a problem for individuals with iron
deficiency anemia, or other low iron conditions.

It is not yet clear what precise factors influence the formation of kidney
stones in men, (other than a high oxalate intake), but because a higher
calcium intake is associated with a higher urinary excretion, it is
generally recommended that men who have a history of kidney stones be
particularly careful to not exceed the general recommendations for dietary
calcium intake, and probably should avoid calcium in the form of
supplements entirely.

As far as deficiency disorders, the most obvious and critical is
osteoperosis - a problem affecting 37 million people in the United States
in 1997. Other bone diseases, dental problems, preeclampsia, colon cancer,
and high blood pressure, all have been directly associated with calcium
deficiency.

And of course, because the body's complex biochemical "symphony" is so
"harmoniously" and carefully balanced, in which every aspect of health is
so completely and intimately connected with every other, the real effects
of a deficiency of this key mineral can only be guessed at.

Love, Liza


--
[log in to unmask] (Liza May)