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Linda Lazarides'
Nutritional Health Bible
an essential reference book for everyone serious about health and nutrition
Treat Yourself with
Nutritional Therapy
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Calcium
Mineral
- UK RNI 700 mg
- US RDA 800 mg
Functions
- Acetylcholine synthesis
- Activation of saliva and many enzymes
- Action of many hormones
- Blood clotting
- Blood pressure regulation
- Conversion of glycogen to glucose
- Muscle contractions
- Nerve impulses (release of neurotransmitters)
- Structure of cells
- Structure of bones and teeth
- Vitamin B12 absorption
Good food sources
- Broccoli
- Cheese (especially hard cheeses)
- Canned fish (if bones are consumed)
- Cow's milk
- Leafy green vegetables
- Nuts
- Pulses
- Root vegetables
- Yoghurt
Deficiency symptoms
- Convulsions and seizures
- Some cases of gum disease
- Loss of muscle tone
- Muscle cramps
- Osteoporosis (brittle bone disease)
- Rickets or osteomalacia (bone softening)
Preventing deficiency
The bioavailability of calcium is reduced by deficiencies of vitamin D and stomach acid, by
high levels of dietary fibre, phytic acid (found in raw whole grains), oxalic
acid (found in spinach) or saturated fat, and by a high protein intake, which
causes increased losses of calcium in the urine. Sodium and caffeine also cause
increased urinary losses of calcium. Very low-fat diets or fat malabsorption may impair calcium absorption. Stress can significantly increase calcium excretion.
60 per cent of calcium is lost when flour is refined. Although by law
many countries require white flour to be fortified with calcium to compensate
for this, the form of calcium which is used (chalk) is considered to have low bioavailability.
A 1985 research study points out that the conditions which produce
calcium deficiency may also lead to a shift of calcium from bone to soft tissue.
This may promote not only osteoporosis but also arteriosclerosis and high blood
pressure, due to increased levels of calcium in the blood vessel walls. Motor
neurone disease and senile dementia could result from the calcium being
deposited in the central nervous system. Another effect of calcium deficiency
may be a shift of calcium from outside the cells (normal) to inside the cells
(abnormal), which would encourage the development of diabetes and immune
deficiency. (Fujita T: Aging and calcium
as an environmental factor. J Nutr Sci Vitaminol 31(Suppl):S15-19, 1985.)
Comments
Many people believe that the regular consumption of dairy
produce (milk, cheese, yoghurt etc.) is essential to prevent calcium deficiency.
This is in fact only true for individuals who eat a diet which would otherwise
be very poor in calcium. The consumption of a good wholefood diet rich in
vegetables and nuts ensures not only a high calcium but also a high magnesium
intake. On the other hand dairy products are a poor source of magnesium, and
individuals who rely on dairy produce for their nutrient intake can end up with
a relative magnesium insufficiency. Calcium deficiency sometimes does not respond to supplementation unless any concurrent magnesium deficiency is also treated. High dietary levels of calcium and potassium can help to prevent some of the harmful effects of excess sodium consumption.
SUPPLEMENTATION
In research studies, calcium supplements have been found to:
- Help prevent and treat some cases of muscle cramps (also
see Magnesium)
- Help prevent and treat some cases of osteoporosis
- Help remove lead, mercury, aluminium and cadmium from
the body
- Reduce allergic symptoms
- Reduce some cases of high blood pressure (also
see Magnesium)
- Together with vitamin D, help treat migraine
- Together with vitamin D, help treat some cases of
hearing loss
- Treat period pains
- Treat premenstrual emotional symptoms and fluid
retention.
Preferred form and suggested intake
Calcium carbonate supplements (usually sold in pharmacies
and sometimes described as dolomite) are in fact identical to chalk or
limestone. They are insoluble in water and cannot be absorbed by individuals who
have reduced levels of stomach acid. Calcium citrate is an economical form of
calcium which is well absorbed. It is usually also advisable to take magnesium
when supplementing calcium, and many combination products are available. Those
with the highest ratio of magnesium to calcium are preferable.
Cautions
A high calcium intake in conjunction with a low magnesium
intake may lead to magnesium deficiency problems such as premenstrual syndrome and "jumpy" nerves.
Adapted from the Nutritional Health Bible by Linda Lazarides
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