The body of an adult contains about 1200gm of calcium. 99% of this is present in skeleton (provides the hard structure of bones & teeth.)
Sources of Calcium : (Mostly white color eatables)
- Cheese, Milk, Yoghurt, Lassi
- Fish and bone
- Nuts e.g. almonds, peanuts
- Egg, bread
Absorption : Calcium absorption is impaired by the lack of vitamin-D.
- 600 mg/day
- 1200 mg/day (in pregnancy & lactation)
- Any reduction of absorbed calcium does not show in the plasma concentration, which is immediately reset by increased parathyroid secretion and formation of 1, 25 dihydroxy vitamin-D.
This is used by the body in the form of phosphate which is present in all cells and so in all plant and animal food and in milk. Dietary deficiency is rare.
Total body phosphorus is about 700 g (mostly in bones).
Dose : 1.5 gm/day
Phosphate deficiency occurs in premature infants fed on human milk. The features of deficiency are hypophosphataemia (decreased plasma phosphorus) and muscle weakness.
A good mixed diet with average amounts of meat and vegetable contains about 12-15 mg of Iron.
Sources of iron :
- Meat, Liver
- Cereals, oatmeal, legumes
Doses : 10 mg/day
Normally, body iron loss from desquamated surface cells adds up to about 1 mg daily. Assuming 10% absorption, about 10 mg are required in diet daily.
Iron deficiency is most common and cause anaemia.
Sign & Symptoms of anaemia :
- Pallor of skin, mucus membranes, conjunctiva
- Breathlessness on excretion
- Insomnia (sleeplessness)
Siderosis : It is due to dietary iron overload. It is seen in African black men who cook in Iron pots.
It is present in the sea, in sea foods and traces in soil and water. Its deficiency causes goitre. Endemic goitre has disappeared in most of Europe and North America due to use of iodised salt.
In remote areas, where iodised salt can not reach, the best way of preventing cretinism is by injecting all women (child-bearing age) with 1-2 ml of iodised poppy seed oil every 5 years.
Fluoride is present in small amounts in bones and teeth. It helps in prevention of dental caries.
Chief sources is drinking water. If it contains 1 part per million (p.p.m.), will supply 1-2 mg/day.
Use of fluoride in prevention of dental carier :
Where the natural supply contains fluoride in amounts of 1 p.p.m. or More, incidence of dental caries is lower than in areas where the water contains only traces of fluoride.
In areas where the water fluoride is high (more than 3-5 p.p.m.), mottling of teeth is common. The enamel loses its lustre and becomes rough.
Zinc is an important nutrient. Zinc supplements accelerate the healing of skin lesions.
Causes of low plasma zinc :
- Intestinal disease
- Chronic alcoholism
- Anorexia nervosa
- Nephrotic syndrome
- Chronic fever
- Mental apathy
- Dematitis especially around the mouth
- Loss of hair
- Nails become light black
Dose : 15 mg/day
Dietary Sources :
- Legumes, nuts
- Whole meal wheat flour, bread, oatmeal
- Wheat bran
Note : Sodium, potassium etc. are discussed in water & electrolyte imbalance chapter (in udakvaha sarotas)