This is an extract from “The Well Balanced Child” by Sally Goddard Blythe
The amount of zinc needed by the body is actually very small, but as with all micro-nutrients, deficiency of even these small amounts can have a profound effect on the functioning of the system as a whole.
Zinc is involved in many metabolic processes in plants and animals. It acts as a catalyst in electron transfer from one molecule to another and it is essential for all protein synthesis and the way in which the body handles carbohydrates and fats. It is necessary for the utilisation of some vitamins and for the formation of blood, enzymes and hormones. It has long been known to promote would healing – hence the high zinc content of various skin lotions such as zinc and castor oil cream used for the prevention and treatment of nappy rahs, calamine lotion and fuller’s earth cream. Zinc infused bandages are also used for the treatment of severe eczema. It is involved in the functioning of the immune system (zinc is often an ingredient of remedies for colds and sore throats such as zinc and vitamin C lozenges) and is involved in reproductive processes in both sexes.
Males need up to five times as much zinc as females in utero for the formation of the testes. Females need increased zinc resources once the ovaries start of function at about 9 years of age when zinc is required with other co-factors for the synthesis of various hormones. Because of the different developmental stages at which zinc is required between the sexes, symptoms of zinc deficiency may show up in a different form according to the age and sex of the child.
Zinc is also necessary for the formation of DNA and RNA – the genetic molecules of life. It is therefore a factor in the expression of genetic potential and deficiency can be passed on from one generation to the next. In her book Sexual Chemistry, Ellen Grant suggest that a number of diseases hitherto considered to be genetic in origin may be related to familial zinc deficiency, which then effects the expression of genetic potential within members of the same family.
Zinc is an essential component of all aspects of development. it is necessary for sperm production, fertility, successful outcome of pregnancy and maternal behaviour. A number of studies carried out on rats have shown that rats fed zinc deficient diets during pregnancy failed to “mother” their offspring: they ignored or rejected their young and failed either to groom or to feed their babies normally. Rat pups reared on a diet with an inadequate supply of zinc showed signs of lethargy, reduced weight gain, inferior performance on two measures of learning ability and increase in emotionality when compared to rat pups who had been reared on a zinc enriched diet.
Growth, sexual maturity, learning ability, stress resistance and behavioural control have all been linked to zinc status in the body. Amongst some of the behavioural changes noted in medical literature are depressions, sensitivity to light, impaired sense of taste and smell, anorexia and bulimia nervosa and impaired concentration. Low zinc levels have also been noted amongst children suffering from post-viral malaise.
The Foresight organisation, which was set up to promote pre-conceptual care, has spent over 20 years researching into the effects of vitamin, mineral and trace element deficiencies on fertility, pregnancy outcome and children who manifest learning difficulties and hyperactivity. Foresight has observed that zinc deficiency seems to be associated with: “poor growth and general development both before and after birth, colic and diarrhoea, poor sucking, late teething and other milestones and generally retarded development both physically and mentally. Hyperactivity, dyslexia and behavioural problems mar the school career and general growth and puberty may be delayed and/or incomplete.”
They go on: “if zinc deficiency is present at birth, the labour may be difficult and delayed, breast feeding may be difficult to establish, bonding may not take place and post-partum depression may set in. Post partum depression and lactation failure have been found empirically to respond well to zinc and vitamin B supplementation.”
Zinc deficiency seems to be a growing problem in the world for a number of reasons. Moder intensive farming methods add a number of fertilisers to the soil, all of which help to produce abundant and apparently flourishing crops. Zinc, however, is not one of the substances regularly put back in to the soil. In the days of crop rotation or when a field lay fallow, the soil had time to regenerate zinc supply for the production of the next crop. In this way, every yield contained an adequate supply of zinc. Many of the plants that we now eat and the animal products that have fed from them, come from soil where the zinc content was low. However “healthy” the diet, it is apparently getting more difficult to ensure an adequate intake of zinc. The modern need to obtain a faster and bigger profit threatens the age-old concept of husbandry, which originally had a triple meaning; “to dwell, to farm and to care for.”
Zinc, lead and cadmium act as antagonists. If lead or cadmium is present in high concentrations (lead may be present in the water pipes of old buildings or in areas where there is heavy traffic pollution; cadmium is present in cigarettes), zinc absorption is compromised – toxic levels of lead and cadmium rise while zinc falls. Equally, zinc deficiency can allow levels of other less desirable trace elements to rise in the body. In the days when water was carried in zinc buckets, the balance was naturally maintained. Although plastic pipes may be more hygienic they do not replenish zinc in the water!
Highly processed foods such as white bread and sugar lose much of their zinc concentration during the processing, while at the other end of the spectrum, excessive consumption of bran and fibre can inhibit the absorption of zinc. Excessive alcohol consumption, smoking, stress and the contraceptive pill can all interfere with zinc metabolism. Zinc, together with chromium, helps to regulate blood glucose levels. Stable blood sugar levels are necessary for the maintenance of concentration, rational thinking and impulse control.
It would be wrong to see zinc as the answer to all ills. it does, however, provide an example of how important it is to maintina a wide rane of individual elements in feeding habits. Shortage of one element can affect the way the body utilizes many others.
Some sources of zinc
Lean meat, oysters, ginger root, oats, egg yolk, whole wheat and rye, haddock, shrimps and tuna, split peas, chicken, lentils, cauliflower, spinach and cabbage. Spices such as black pepper, paprika, chilli powder and cinnamon are also good sources of zinc.