It's well known that adequate calcium is essential for the
maintenance of strong, healthy, bones and teeth, and indeed
this is where around 99% of the approximately 1.2 kg stored
in the average adult human body is to be found. But this
is not in fact this vital mineral's most important function
within the body, because calcium is also needed in the
blood in very precise quantities to ensure that certain
vital physiological processes can carry on unimpaired.
These include the constriction and dilation of blood
vessels - essential for the body's internal temperature
regulation, the transmission of nerve impulses, the release
of energy for muscle contraction, the secretion of certain
vital hormones such as insulin, and the clotting of the
blood.
As evidence for the importance of these functions it is
only necessary to observe that the body will strip the
bones of calcium in order to maintain the necessary blood
levels of the mineral should these be in danger of falling
too low because of inadequate dietary intake. Since the
bones, like all the body's structures, are in a constant
state of regeneration and repair, the potential
consequences if this deficiency is allowed to persist over
time can be catastrophic.
In extreme cases, deficiency in children and adolescents
may lead to the weakness and malformation characteristic of
the disease, rickets. In adults, especially older adults,
the most obvious consequence may be the loss of bone
density known as osteoporosis - a major cause of the
greatly increased incidence of the serious fractures which
are such a significant risk factor for the health of the
elderly.
But there are other problems which may be associated with
low intakes of calcium.
There is good evidence to implicate low calcium intake as a
risk factor for the development of high blood pressure
during pregnancy (pre-eclampsia) in those women who are
susceptible to this potentially dangerous condition; and,
interestingly, research has shown that supplementation with
calcium to a daily intake of 1,000 - 1,200 mg a day may
also be effective in reducing blood pressure in the general
population. A number of studies have linked low levels of
calcium with pre-menstrual syndrome (PMS) and indicate that
supplementation may help reduce the severity of these
symptoms.
There is even now some evidence that low calcium intakes
may tend to encourage the body to deposit more fat within
existing fat cells. Although the relationship is not fully
understood, it appears safe to say that a plentiful supply
of dietary or supplemental calcium is essential for success
in the pursuit of any weight loss program.
Given the importance of calcium in all these ways, it's
alarming to note that average intakes for most people in
the developed world are known to fall well short of the
suggested level, and the figures are particularly serious
for adolescents whose growing bones who have the greatest
need. Perhaps as many as 75% of boys and 90% of girls in
this age group may be calcium deficient.
Dairy products are by far the best sources of dietary
calcium and an 8 oz serving of milk or yoghurt, or 1 ½ oz
of cheese, will provide around 300 mg of calcium. Leafy
green vegetables, with the exception of spinach, are also a
useful source, although you would need 3 - 4 servings of,
for example, broccoli or kale, to match the calcium
obtained from a single standard glass of milk. It should
also be realised that The consumption of diets high in
protein and salt, ie those characteristic of the affluent
Western world, is known to increase the excretion of
calcium and consequently the risk of deficiency and
associated problems with bone strength and health.
Owing to this, and a number of other possible variables
affecting the individual's need for dietary calcium, the
Food and Nutrition Board has set out figures for Adequate
Intake (AI) of the mineral rather than the Recommended
Dietary Allowance (RDA) which it commonly prescribes for
vitamins and other vital nutrients. Babies and infants
should begin with an intake of around 200 mg per day,
rising to 800 mg by the age of eight. Children of nine and
over, young people whose bones are still growing, the over
50s, and pregnant or breast-feeding women, will have higher
needs and should aim to consume 1,200 -1,300 mg of calcium
a day.
To maintain the health and density of fully formed bones,
adults between about 20 and 50 should aim to consume 1,000
mg of calcium daily, through a combination of diet and
supplements. In all cases, combining this supplementation
with at least 400 IU of vitamin D will greatly assist with
the absorption of the necessary calcium.
Calcium supplements should also always be taken with food;
the recommended upper safe limit for total calcium intake
being 2,500 mg, below which there should be no problems.
However, since high calcium intakes can adversely effect
the absorption of other essential minerals, notably
magnesium, zinc and iron, it is recommended that
supplementary calcium should always be taken as part of a
comprehensive multi-mineral supplement.
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Steve Smith is a freelance copywriter specialising in
direct marketing and with a particular interest in health
products.
Find out more at
http://www.sisyphuspublicationsonline.com/LiquidNutrition/In
formation.htm
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