Appendix V – Deficiency and excess of vitamins and minerals

Vitamins

Vitamins are needed in very small amounts for healthy growth and development. They cannot be made by the body, and so must be obtained from diet. A healthy, varied diet will supply all the vitamins (and minerals) you need to stay healthy. However, you can have too much of a good thing and hypervitaminosis is the name given to excessive consumption of vitamins, which has become fashionable with some groups of people, particularly in the USA.

While this is not serious with water-soluble vitamins where any excess is simply excreted in the urine, it can be very serious if fat-soluble vitamins are taken to excess, as the body will store them in the body fat, resulting in a toxic build-up. Vitamins A, D, and E are all fat soluble and so liable to cause a toxic build-up in excess. All the other vitamins are water soluble. Vitamins A, C and E act as antioxidants, helping to protect us by reducing the likelihood of serious diseases, such as heart disease and possibly even some types of cancer. Vitamins generally act as co-enzymes and, without them, certain enzymes would not function properly.

Vitamin A is fat soluble and is very toxic in overdose. Liver is a rich food source of vitamin A, so rich that expectant mothers are advised not to eat it during pregnancy because high doses of vitamin A have been associated with birth defects in the past. Oily fish such as cod, halibut and salmon are all rich sources of both vitamins A and D.

A precursor of vitamin A, beta-carotene, is the orange pigment found in carrots, which is converted in the body to the active form, known as retinol. Beta-carotene is also present in red, orange and yellow fruit and vegetables. Vitamin A is essential for growth, for the maintenance of soft mucous tissue and particularly for vision in dim light, so eating carrots really can help you see in the dark!

Yet again, it should be noted that it is important not to cross the line between benefit and excess: in the 1960s a woman in America died from a vitamin A overdose. She had decided to lose weight by restricting her diet to simply drinking carrot juice. When she died, her flesh was found to be tinted a strange orange colour, due to the build-up of beta-carotene in her tissues.

As well as excess, deficiency of vitamin A can also cause trouble, as it leads to stunted growth and visual problems, initially affecting only night blindness, but, if not treated, progressing to more serious optical disorders and eventually complete blindness.

Vitamin B is not a single entity but is composed of a number of vitamins in what is called the B group complex. They are all water soluble and all act as co-enzymes – this means that, without them, certain enzymes would not function properly. Although not chemically related to each other, the B group vitamins are often found together in the same types of food, such as milk and cereals.

Thiamine, vitamin B₁, is found in liver, pork, wholegrain cereals, pulses, nuts, milk and bread. Thiamine is involved in carbohydrate metabolism, and a deficiency of this vitamin leads to the condition known as beriberi. This nutritional disorder is widespread, even today, in the rice-eating communities of the world, where polished rice is eaten. Polished rice has had the seed coat removed and discarded, but unfortunately it is the seed coat that is rich in thiamine.

Two forms of this disorder can be distinguished: wet beriberi is so called because there is an accumulation of fluid and swelling (oedema) within the tissues, while with dry beriberi there is extreme emaciation. Both forms cause nervous degeneration and often result in death from heart failure. Thiamine deficiency is often seen in chronic alcoholics or as a result of prolonged deliberate fasting, as in anorexia.

Riboflavin, vitamin B_2, is important in tissue respiration and essential for the utilisation of energy from food. Excessive doses of riboflavin result in the urine becoming a bright yellow colour, which has been known to interfere with some laboratory tests. A deficiency results in a condition with symptoms including inflammation of the tongue and lips, with sores at the corners of the mouth. Such a condition is soon remedied by eating green vegetables, fish, liver or eggs.

Pyridoxine, vitamin B₆, is crucial for the production of a vital co-enzyme called pyridoxal phosphate, essential for carbohydrate and fat metabolism and for the formation of haemoglobin. It is also involved in the functioning of the nervous system. An excess can cause problems leading to the development of severe peripheral neuropathies, with tingling, pins and needles and loss of sensation in the fingers and toes. A deficiency of pyridoxine can lead to the development of a type of anaemia, dermatitis and even convulsions. Deficiency is rare, as pyridoxine is found in most foods; however, a deficiency state can be drug induced or can result from an inborn error of metabolism.

Genetics has an important effect on metabolism. Certain racial groups of people tend to metabolise some drugs at a much slower rate than others, which can result in a toxic build-up of the drug or its metabolites. A normal dose for one person who metabolises the drug rapidly would be harmfully toxic to someone else who metabolises it slowly. Such a patient, if given a drug called isoniazid, used in the treatment of tuberculosis, would need not only a lower dose of isoniazid but, additionally, pyridoxine to ensure that they did not suffer such toxic effects as convulsions. Such slow metabolisers have been found to respond better to treatment with isoniazid, but they are also more likely to develop peripheral neuropathy, with tingling fingers and toes. And they are found to be at greater risk of an adverse effect on their liver function in some cases too.

Cyanocobalamin, vitamin B₁₂, as the name suggests, contains both cyanide and cobalt. Vital for the synthesis of nucleic acids, the maintenance of myelin that sheaths the nerves and the proper functioning of folic acid, another of the B group vitamins, vitamin B₁₂, can only be absorbed from the gut in the presence of a substance called intrinsic factor.

This substance is normally secreted by the stomach, but if the body fails to secrete it, then a deficiency of vitamin B₁₂ results, quite simply because the gut cannot absorb it. This leads to the development of pernicious anaemia, and results in the degeneration of the nervous system if not treated with injections of vitamin B_12. This vitamin is only produced by certain micro-organisms and is only contained in foods of animal origin including meat, liver, fish and eggs. Therefore, strict vegetarians, and vegans particularly, need to supplement their diet with this vitamin to avoid the development of pernicious anaemia, due to a lack of this vitamin.

Biotin, sometimes referred to as vitamin H or co-enzyme R, is another member of the B group complex essential for the metabolism of fat and protein. Egg yolk and liver are rich sources of biotin, so a deficiency of this vitamin is rare. However, patients receiving long-term total parenteral nutrition can become deficient in biotin, as can those with certain inherited metabolic disorders.

Folic acid is another member of the B group complex. It is important in the synthesis of nucleic acids and is interdependent with cyanocobalamin. A deficiency of one can lead to a deficiency of the other. A deficiency of folic acid can lead to megaloblastic anaemia in which red blood cells do not form or mature properly. Foods rich in folic acid are green vegetables, pulses, liver, wheatgerm and yeast extract.

It was only about 20 years ago that the importance of folic acid in the diet of pregnant mothers was fully realised. Today, women intending to become pregnant are recommended to take a daily tablet of 400 micrograms of folic acid for the three months before conception and the first three months of the pregnancy to prevent neural tube defects, such as spina bifida and other congenital malformations like cleft lip and cleft palate in their baby.

Nicotinic acid, vitamin B3 is found in oily fish, meat, whole cereals and nuts. It is also called niacin and is interchangeable with nicotinamide, as both forms are equally active in cellular respiration. Nicotinic acid can be made in the body from the amino acid tryptophan (see the section on protein later in this chapter), and is converted to the active form – nicotinamide – in the body. A deficiency of either nicotinic acid or tryptophan leads to pellagra, a condition commonly found in maize-eating communities. This is because the nicotinic acid in maize is only present in a chemically bound form that prevents its absorption from the gut. This binding makes the vitamin unavailable to those who eat the maize. The symptoms of pellagra are a scaly type of dermatitis, together with diarrhoea and depression.

Pantothenic acid, or vitamin B5, another member of the B complex group, is a component part of coenzyme A, which is important in the body’s use of carbohydrates, fats and proteins and also in the metabolism of fatty acids. No deficiency state has ever been seen thanks to the presence of pantothenic acid in so many foodstuffs.

Ascorbic acid, vitamin C, is a water-soluble vitamin that has antioxidant properties. It is essential for the synthesis of collagen, the maintenance of healthy connective tissues and the integrity of cell walls. Citrus fruit and vegetables are all rich sources of this vitamin. Deficiency of vitamin C leads to scurvy, a condition common to sailors centuries ago caused by the lack of fresh fruit and vegetables in their diet during long sea voyages.

Vitamin D is a fat-soluble vitamin that enhances the absorption of calcium and phosphorus from the intestine and promotes their deposition in bone. The daily dose measured in micrograms is essential to growth and development. A good dietary source of both vitamins A and D is to be found in fish oils.

Vitamin D occurs in two forms: ergocalciferol, from plants, and cholecalciferol, produced by the action of sunlight on our skin. So, a deficiency can be due to either poor diet or to lack of sufficient sunlight, or both, resulting in decalcified bones and the development of rickets and osteomalacia. Based on findings that the number of cases of multiple sclerosis increases the further north sufferers live in the northern hemisphere, recent and ongoing research suggests that the condition may be caused by the interaction of a genetic variant together with lack of sunlight, and hence a deficiency of vitamin D production in the skin. However, vitamin D is toxic in large doses.

Vitamin E is a generic term that refers to any one of a group of chemically related fat-soluble compounds. These compounds are antioxidants, thought to stabilise the cell membranes by preventing the oxidation of their unsaturated fatty acid components, thus preventing deterioration in healthy cells. Otherwise this might result in the deposition of abnormally large amounts of fat within the cells. Such a build-up of fat predisposes to thrombosis. It is for this reason that it was suggested that taking a daily supplement of vitamin E might reduce the risk of coronary thrombosis in those with heart disease. Coronary thrombosis is the formation of a blood clot in one of the coronary artieries, which obstructs the flow of blood to part of the heart and results in the death of a segment of heart muscle; that is, the patient has a heart attack.

Large doses of vitamin E can cause diarrhoea, abdominal pain and other gastro-intestinal disturbances. The absorption of vitamin E from the gut is dependent on the presence of bile and also on normal pancreatic function. Vitamin E deficiency is uncommon, but can occur in rare cases where there is a problem with fat absorption due to an inherited disorder.

Vitamin K is another fat-soluble vitamin that exists in two forms: phytomenadione, of plant origin, and menaquinone, of animal origin. Vitamin K is vital for the formation of the blood-clotting factor prothrombin, and of several other clotting factors. This vitamin is synthesised by bacteria (friendly bacteria) in the large intestine and is also present in green, leafy vegetables, so a dietary deficiency is rare. All newborn babies are given an injection of this vitamin shortly after birth to ensure they have a sufficient supply to deal with any bleeding that may have occurred internally during delivery.

Minerals:

Certain minerals are essential to the human diet, frequently acting as cofactors in enzyme systems or as part of other complex molecules. The minerals required are calcium, phosphorus, potassium, sodium, iron, chlorine, sulphur and magnesium, in addition to trace elements, including manganese, zinc, copper, iodine, cobalt, selenium, molybdenum, chromium and silicon. Problems may arise when the body is unable to use them as nature intended.

Calcium is essential for the normal development and functioning of the body. It is an important constituent of bones and teeth. About 99 per cent of the body’s calcium is to be found in the bones, mainly as calcium phosphate. Some of the remaining one per cent is to be found in the bloodstream, where its level is maintained by hormones. The presence of calcium is essential for many metabolic processes, including blood clotting, nerve function and the contraction and relaxation of muscles.

The parathyroid glands, which are situated in the neck, are responsible for the secretion of the parathyroid hormone, which regulates both the calcium and phosphate levels in the body and also controls their distribution in the blood and the bones. Hypercalcaemia, a high blood level of calcium, may, rarely, be due to vitamin D toxicity, but may also be caused by hyperparathyroidism, acute renal failure, malignancy or even by chewing too many calcium carbonate antacid tablets; this can result in the so-called milk-alkali syndrome. Conversely, in hypocalcaemia, a decrease in plasma levels is seen, which may be due to vitamin D deficiency, chronic renal failure or low parathyroid levels. A low calcium blood level can lead to tetany, while an excess can result in the formation of calculi, that is, stones, in the gall bladder or kidneys.

Phosphorus is mainly found as calcium phosphate in the bones and teeth, but phosphorus is also vital in compounds involved in energy conversion and storage in the body. Osteomalacia and rickets are both caused by vitamin D deficiency, to which phosphate deficiency may also contribute. Phosphate deficiency can occur in premature babies who have been exclusively fed on human breast milk; they need to be given supplements to help them grow well. Phosphate is usually given medicinally as sodium phosphate or potassium phosphate, both of which are readily absorbed by the body.

Phosphorus poisoning can result in destruction of tissue, due to excessive amounts of phosphorus in the system, and can affect the liver, kidneys, muscles, bones and cardiovascular system. A raised plasma-phosphorus concentration in the blood is usually associated with kidney failure, but it can also be due to decreased levels of parathyroid hormone. Low phosphate levels can be caused by an inherited X-linked genetic disorder, or increased parathyroid levels, insufficient absorption of phosphate or even the previously mentioned vitamin D deficiency.

Sodium is continually being lost from the bloodstream as it passes through the kidneys and, although much is recycled, some is still lost via the urine, faeces and sweat, so a regular supply from the diet is required. Sodium chloride – salt – comes from mineral deposits of rock salt or as sea salt which was extracted from sea water. Table salt is sodium chloride with a little magnesium carbonate added to make it free flowing. Iodised salt has a little potassium iodide added to it.

A deficiency of sodium, which can occur as a result of severe diarrhoea or vomiting, through profuse sweating or the prolonged use of diuretic drugs, causes muscle spasms or cramp, weakness, tiredness, dizziness, confusion, fainting and palpitations. Treatment is very simple – by replacement with more salt. Normal saline is a 0.9 per cent solution of sodium chloride in water. This particular strength, being isotonic with body fluids, is used intravenously as it does not upset the body’s fluid balance.

In tropical countries, salt saves millions of lives when used as a treatment for diarrhoea. Rehydration sachets of sodium and potassium salts, together with glucose, are dissolved in boiled water and given to those suffering from diarrhoea and cholera to rehydrate them. If left untreated, dehydration can be rapidly fatal. Glucose is included to provide the body with an energy source, needed by the gut, to absorb both the salts and the water.

People who have high blood pressure, heart trouble or kidney disease are usually told to reduce their salt intake as a means of reducing the sodium content of their diet. This is because if the heart or kidneys are diseased, they are less able to remove excess salt. They compensate for this by retaining extra water, which in turn results in an increase of the blood pressure, to the detriment of the patient.

The emetic effect of a sudden increase in sodium has traditionally been used in the form of salty water to make people vomit following ingestion of poisons, although today this is considered to be a dangerous practice.

Iron is essential to life. We each have about four grams of iron in our body, about enough to make a small nail, over half of which is contained in the haemoglobin within the red blood cells. The rest is distributed around the body as myohaemoglobin, in the muscles, in cytochromes and as iron storage substances in the body tissues. Meat, particularly liver, is a rich dietary source of iron.

Iron deficiency is given the medical name anaemia, but there are a number of different types, each with a different cause, some of which are genetic, as also are some of the diseases caused by too much iron in the body. Treatment is dependent on the cause and, in many cases, is symptomatic.

Iron-deficiency anaemia is caused by blood loss, malabsorption or inadequate iron intake.

Megaloblastic anaemia is caused by a deficiency of folic acid, or of vitamin B₁₂, or malabsorption because of a lack of intrinsic factor, as in pernicious anaemia, already explained earlier in this appendix under cyanocobalamin – vitamin B₁₂.

Aplastic anaemia can be inherited, but may be acquired from a variety of causes, such as from the effects of cytotoxic drugs, radiotherapy during treatment for cancer, auto-immune reactions, idiosyncratic reactions to other drugs or even viral infections, such as hepatitis C. If left untreated, this type of anaemia can be fatal; however, a bone-marrow transplant, from a suitable donor, will restore bone-marrow function.

Haemolytic anaemia can be congenital or acquired, either as a disorder of the immune system or as a result of toxicity caused by such toxins as copper and arsenic, snake venoms or even some drugs. Sickle-cell disease and thalassaemia are hereditary blood diseases due to genetic defects in the haemoglobin, each caused by a different abnormality of the protein part of the haemoglobin molecule. Treatment in each case is by the administration of repeated blood transfusions. But while this replaces the lost sickle cells, so treating the anaemia produced in sickle cell disease, there is an iron build-up in thalassaemia which is treated with iron chelators, mentioned in the chapter on treatment.

Enzyme defects, such as various forms of glucose-6-phosphate dehydrogenase deficiency, are X-linked hereditary conditions, in which the absence of the enzyme glucose-6-phosphate dehydrogenase, normally part of carbohydrate metabolism, results in the breakdown of red blood cells (haemolysis). This can happen after exposure to infection or to oxidants in some foodstuffs and certain drugs such as methylene blue, which have been mentioned in the treatment chapter.

Treatment involves identifying and avoiding those agents that trigger the haemolytic anaemia, as well as treating attacks symptomatically. There are several varieties of this type of anaemia, linked to racial origin: an African version which is sensitive to some antimalarial drugs, an Oriental one and a European version, including Favism, which occurs in parts of the Mediterranean and Iran. Favism causes red blood cells to become sensitive to a chemical in broad beans (fava beans). It destroys the red blood cells leading to severe haemolytic anaemia, which is treated with blood transfusions.

Too much iron: There are disease states caused by both an excess of iron as well as by a deficiency. A genetic disorder, haemochromatosis, also known as bronze diabetes, is an iron storage disease that can lead to a build-up of iron in the body and results in the impairment of, and damage to, many organs, including the liver, pancreas and other endocrine organs. The build-up is manifest as a bronze colour to the skin, together with diabetes and liver failure.

Patients who suffer from thalassaemia, an inherited anaemic disease, also have problems due to a build-up of iron because of their treatment. They have an abnormality of the protein part of the haemoglobin molecule, which can be treated by the administration of multiple blood transfusions. Unfortunately this also gives the patients extra iron that is not needed, so they also take drugs to help them get rid of this build-up of excess iron.

Magnesium is another mineral essential to life. We each have about 25g of it in our body, concentrated mainly in the bones. Magnesium is a cofactor in at least 90 enzyme systems needed for the proper functioning of our muscles and nerves. Our main dietary source of magnesium is green, leafy vegetables.

Too little magnesium can cause problems, such as a deficiency state that can occur in alcoholism. Lack of magnesium can lead to lethargy, irritation, depression and personality changes – symptoms similar to delirium tremens.

Potassium is found mainly inside but also to a lesser extent outside every cell in our body. This mineral is essential to life and, together with sodium, is vital for the normal functioning of the nervous system and muscle. A deficiency state can occur when the kidneys malfunction, during starvation and in patients taking long-term loop diuretics like frusemide; indeed, the latter is such a problem that some diuretic preparations are formulated with potassium included to provide a built-in replacement for this loss. Severe dehydration, such as from a bad bout of diarrhoea, can cause a temporary deficiency of potassium, accompanied by a feeling of weakness. This resultant muscle weakness can affect the heart if severe, causing irregular beating and even cardiac arrest and death.

Too much potassium can also cause problems. The excess potassium tends to depress the central nervous system, and large doses can paralyse it, causing convulsions, diarrhoea, kidney failure and cardiac arrest. Patients have died from cardiac arrest following a direct injection of potassium chloride straight into a vein – it needs to be added to 500ml of normal saline and then slowly infused over a period of several hours.

Indeed, injection of potassium chloride directly into a vein is the lethal injection used as a form of capital punishment in the USA, with death resulting from cardiac arrest.

The injection of potassium chloride has also been used in cases of multiple pregnancy, where medical staff considered that selective reduction was necessary. This is achieved by the injection of potassium chloride into the chosen foetal thorax in utero to abolish its cardiac activity without affecting the other babies, which are then allowed to continue to term.

Copper is another essential element that we acquire from our diet. This mineral is good at what it does but is dangerous in excess or deficiency. It is also a vital component of a number of enzymes, without which we cannot live.

A build-up of copper can occur in Wilson’s disease, an inborn metabolic disorder caused by the body’s inability to utilise copper properly. Free copper is deposited in the liver, causing jaundice and cirrhosis. It also accumulates in the brain, resulting in mental retardation and other symptoms similar to those of Parkinson’s disease. The corneas in the eyes become stained with a characteristic brown ring.

The cause of this condition is a congenital deficiency of a copper-containing protein, caeruloplasmin, normally present in the blood plasma. This protein normally forms a non-toxic complex with copper, which can then be excreted.

Menke’s disease is an X-linked genetic disorder, caused by chronic lack of copper. This is because the body is unable to make the copper-transporting protein required, which leads to retarded growth, cerebral degeneration and death in infancy.

Zinc is yet another mineral essential to life, and high concentrations are to be found in the eye, prostate, muscle, kidney and liver. Semen is rich in zinc, and a deficiency of this mineral results in low sperm counts. As zinc is involved in many enzyme systems and transcription factors in our cells, a deficiency of zinc in the long term will result in stunted growth, retarded sexual development and taste disturbance.

However, control of zinc can be used for the good. The rare genetic disorder acrodermatitis enteropathica, which used to be fatal to all babies born with it, can now be successfully treated with zinc salts. Alcoholics frequently need to take zinc supplements as the enzyme alcohol dehydrogenase, involved in breaking down alcohol, contains a zinc atom. Due to alcoholics’ excessive consumption of alcohol, they need more of this enzyme and therefore more zinc. As always though, it’s a tricky balance: very large doses of zinc supplements may inhibit the absorption of copper and so cause other problems.

In Bangladesh, mothers given zinc supplements during pregnancy gave birth to healthier babies, who were less likely to die from diarrhoea or pneumonia, both major killers in the developing world. A weekly dose of zinc reduced the death rate by 85 per cent. So simple, yet so effective.

Iodine is essential not only for normal human growth and development, but also for a normal life span. Most of the 30mg of iodine in our bodies is found in the thyroid gland, where it is used to make two hormones, thyroxine and tri-iodothyronine, which are both involved in regulating our metabolism.

Hypothyroidism, caused by a deficiency of iodine, makes a person feel listless and cold, and tends to cause weight gain. This condition can eventually lead to the development of a goitre, where the thyroid gland enlarges, causing a swelling of the neck, in an attempt to produce more thyroid hormones.

At the opposite extreme, too much thyroid hormone causes hyperthyroidism, resulting in restlessness and hyperactivity. Hyperthyroidism, also called Graves disease, after the Irish physician Dr R. J. Graves (1850-1932), is also referred to as thyrotoxicosis and can result in the development of exophthalmic goitre, with a swollen neck and bulging eyes resulting from the enlarged thyroid gland. This condition tends to result in weight loss. The symptoms of thyrotoxicosis can be caused by simple overgrowth and thus over-activity of the thyroid gland, by a hormone-secreting benign tumour or by carcinoma of the thyroid gland.

Treatment may be by surgical removal of the thyroid gland, by administration of radio-active iodine to destroy part of the gland or by use of drugs such as carbimazole, which interfere with the production of the thyroid hormones. Whichever treatment is used, the goal is to end up with the patient slightly deficient in thyroxine, as this can then be easily treated with daily thyroxine tablets.

Iodine is particularly important for the development of the nervous system: babies born to mothers deficient in iodine during pregnancy have been found to suffer from cretinism. Cretinism is a syndrome of dwarfism and mental retardation, with a coarseness of skin and facial features due to a congenital lack of the thyroid hormone from birth. However, too much iodine can cause problems too, as it can lead to iodine poisoning, the main features of which, if mild, are an odour on the breath and staining of the mouth. Seaweed, also called kelp and bladderwrack, is a rich source of iodine. It is included in a number of herbal slimming products, on the premise that an increased iodine intake might speed up the body’s metabolism sufficiently to help with the desired weight loss.

Selenium was only proved to be essential to life in 1975. It is stored by the body in red blood cells, the liver, spleen, heart and nails and then converted in the tissues to metabolically active forms. It is excreted mainly in the urine, with a little also in the faeces.

Only required in very small amounts of less than half a milligram per day, it is possible to overdose without even realising. As little as five mg taken as a single dose will produce toxic symptoms such as foul breath and body odour. An overdose of selenium causes loss of hair, nail changes, diarrhoea, dermatitis, a garlic odour to the breath, fatigue and peripheral tingling fingers and toes.

Selenium is present in many foods, mainly in the form of amino acid compounds, selenomethionine and selenocysteine. However, selenium intake in the UK has dropped markedly since we stopped importing wheat from North America and began using European-grown wheat instead. The selenium in European soils was stripped out during the last ice age, but this was not the case in North America.

A dietary deficiency of selenium is associated with a form of cardiomyopathy called Kershan disease, endemic in one part of China where little selenium is present in the soil and thus little is present in the foodstuffs grown there.

Sodium selenite is used as a source of selenium for those patients who develop deficiency states. This can be the case following prolonged periods of total parenteral nutrition. Low selenium levels have been shown to lead to low sperm counts, and men who took a selenium supplement could double their sperm count and so increase their fertility. Studies have also shown a correlation between low selenium intake and risk of prostate cancer – another good reason for men to take a selenium supplement.

Trace elements:

As already mentioned, the body is a complex machine that requires so many different ingredients in the proper quantities to function and maintain balance. Trace elements are just that, only a minute quantity being required, but, nonetheless, absolutely essential.

Manganese is involved in a number of our enzyme systems and is stored in the brain, kidneys, pancreas and liver. Accumulation of manganese can occur in patients, particularly children, receiving long-term total parenteral nutrition. If manganese dust is inhaled by miners in badly ventilated mine workings, it results in brain damage and other symptoms that appear to be very similar to those of patients diagnosed with Parkinson’s disease.

Cobalt is a vital trace element that forms part of vitamin B₁₂. A deficiency of this vitamin can lead to pernicious anaemia.

Molydenum is needed for healthy teeth, for the functioning of some enzymes and also for the male sexual libido.

Chromium is involved in enzyme systems for carbohydrate and fat metabolism as well as for the production and action of insulin.

Silicon is needed for healthy skin, hair and nails.

Fluorine is an important trace element which, when incorporated in tooth enamel as a fluoride – a compound of fluorine – makes teeth more resistant to dental decay. In addition to creating healthy teeth, fluoride is also needed for bones, muscles and blood vessels. Our water supplies contain about one part per million of fluoride, due either to the natural mineral content or the addition of the element by the water supplier. In acute fluoride poisoning, when sodium fluoride is taken by mouth, it produces the very corrosive hydrofluoric acid in the stomach. Other effects of fluoride poisoning include tremors, tetany and convulsions, leading to cardiac and respiratory arrest. Death results within two to four hours following a dose of as little as 5-10mg of sodium fluoride.