Factors that affect Calcium Status

Adequate vitamin D is needed for calcium absorption and utilisation. It can be synthesised in the skin in response to sunlight.

A diet high in protein increases calcium LOSS and results in higher calcium requirements.

Healthy calcium metabolism is dependant on the presence of magnesium. When there is too little magnesium calcium cannot be incorporated into bone mass, muscles become overtight and don’t relax or there may be cramps.

A high fat diet reduces the availability of calcium and can produce a net deficiency.

A diet high in acid-forming foods such as sugar, coffee, red meat, dairy, and salt all upset the calcium metabolism causing calcium loss from bones.

Calcium requires there to be sufficient acidity in the stomach in order for it to be absorbed. Many people, especially the elderly, tend to have decreased levels of stomach acid, and therefore become calcium deficient.

Poor absorption from the gut can cause calcium deficiency. Such conditions are coeliac disease, intestinal hurry, chronic intestinal infections and pancreatic insufficiency.

Oestrogen's tend to help protect the bones from the actions of parathyroid hormone which increases the rate at which calcium is reabsorbed from bone into the blood stream. When the menopause happens, there is less oestrogen and so the actions of parathyroid hormone are greater increasing bone calcium loss. However the general acid levels in the body also affect calcium reabsorption adding to the problem of bone loss, see above.

Exercise seems to increase bone density.

Phosphorus which is present in many processed foods and in fizzy drinks increases the need for calcium.

Dosage and Toxicity

When taking calcium it is important to ensure that it is in an absorbable form. Dolomite is a cheap calcium supplement and is relatively unabsorbable. It may also be contaminated with toxic metals such as lead, arsenic, mercury and aluminium so it is best avoided. Calcium carbonate is also poorly absorbed. Good sources of Calcium are calcium citrate, gluconate, or orotate. Also amino-chelated calcium.

The RDA (Recommended Daily Allowance) is 800mg. However actual individual needs vary enormously and are dependant on some of the factors mentioned above, not least of which is diet. If one is eating a poor diet, high in red meats, sugar, coffee, dairy products, then one would have an increased requirement.

Too much calcium can lead to many problems such as kidney stones, poor muscle tone, constipation, abdominal pains, loss of appetite, nausea, deposition of calcium in sites outside bone, and in soft tissue forming fibroids.

Good food sources of Calcium are:

It is easy to get the right amount of calcium if you eat a healthy diet consisting of lots of green leafy vegetables, especially broccoli (but not spinach whose oxalate content reduces its bioavailability), nuts, seeds, pulses and whole grains.

Although milk contains lots of calcium it is not a good source of the mineral as it is relatively poorly absorbed from milk, and the mucus forming ability of milk in many people make this even more difficult. Milk also forms acid bi-products which increases calcium leaching from the bones.

Osteoporosis and Calcium

Many people diagnosed with osteoporosis or thinning bones are advised to take calcium supplements to replace the calcium lost from the bones. However calcium supplements on their own cannot and will not reverse or even stabilise the bone loss. A person with osteoporosis may have enough calcium in their body but it is not in the right place. Such people often have bone growths or calcium deposits in odd places in the body because the body has ‘dumped’ it there due to metabolic conditions. This happens more often when a person is over-acid as mentioned above. The body uses the bone store of calcium as a buffer for the high levels of dangerous acid that is taken in from the diet or produced as a result of body processes. More calcium in the diet or as supplements will just lead to more calcium ‘dumping’ and no more in the bones.

Another reason why calcium is lost from bone is when there is a magnesium deficiency. These two minerals act in partnership and both are needed for balanced metabolism.

In order for osteoporosis to be halted or even reversed an alkaline-forming diet consisting of high levels of vegetables, fruits, and whole grains is important. Acid forming foods such as sugar, lots of red meat (ie meat on a daily basis), tea, coffee and dairy should be minimised. A supplement containing both calcium and magnesium is important and they should be at least in equal amounts if not twice as much magnesium. A good bone supplement also contains vitamin D and Boron which also help with healthy bone formation.

Exercise that pushes the body away from gravity such as walking or bouncing is good as the up and down motions help to tell the body to keep bones strong. Swimming which is a weightless exercise is not so helpful.

If you have any further questions or worries then it is a good idea to consult a nutritional therapist.

Insulin is one of the hormones that helps to control blood sugar levels by enabling glucose to enter cells. Glucose is the fuel that cells use for generating energy to make all cell processes happen. If the body fails to control blood sugar levels with insulin then levels rise above normal and the person has diabetes mellitus. Chromium in the form of GTF has the effect of facilitating and augmenting the action of insulin, making it more effective in its role of controlling blood sugar. In view of this it is not surprising to learn that diabetes is often associated with chromium deficiency and that chromium supplementation may help in the nutritional treatment of diabetic subjects.

Often before a person becomes diabetic they suffer for several years from fluctuating energy levels often accompanied by mood swings and a range of other minor ailments. This is due to a pre-diabetic condition called hypoglycaemia or low blood sugar. Lack of Chromium leads to inability to control blood sugar levels so the levels seesaw from high to low causing the fluctuating energy levels and other symptoms. The brain is highly dependent on a constant supply of glucose to function normally so when levels drop panic attacks, migraines, irritability, behavioural problems and insomnia can result.

Chromium has also been shown to be essential for optimum growth and it also has a controlling action on blood lipid (fat and cholesterol) levels. It seems that when there is a deficiency, aortic plaques are formed spontaneously, causing narrowing of the arteries. People who have heart attacks are usually found to have extremely poor chromium status.

Foods that are rich in chromium are molasses, whole wheat, egg yolk and black pepper. There are moderate amounts in hard cheese, beef, oysters, butter and rye, also found in parsnips and apples. Refined foods such as sugar and white flour have negligible amounts of chromium and yet these are the foods that most require the presence of chromium for them to be utilised in metabolism. Hence a diet high in sugar and refined flour leads to higher requirements but lower intake of chromium and consequently to greater problems with controlling blood sugar leading to conditions of hypoglycaemia and diabetes.

How much do we need? Chromium is best supplemented in its GTF form as this is its most absorbable form and then 8 to 30 mcg/day is sufficient. In inorganic form 200 to 300 mcg is required in order for 20 mcg to be absorbed. Best of all is to eat foods rich in chromium.

Copper is essential to health as it is needed for all tissue respiration as part of an enzyme called cytochrome oxidase. It is needed for the formation of haemoglobin, the myelin sheath around nerve fibres, maintaining the integrity of the skeleton, for the metabolism of vitamin C, for forming the pigment melanin in hair and skin and in other essential enzymes. Most copper in the body is held in the brain, the heart and the kidney, while a smaller portion is to be found circulating in the blood.

Although copper is so vital to many processes we only need a little each day, about 2 mg. Copper has a very close relationship to zinc which has been the subject of a previous article. In both plants and animals, zinc and copper compete for absorption and when levels of one are high, the other is very poorly absorbed. If we eat too many copper rich foods we will become deficient in zinc and vice versa, so it is important to keep the ratios to the optimum levels of 1:7, for correct absorption. Copper is found in oysters, kidney, dried legumes, liver and nuts. It is also present in any water that has passed through copper pipes, which is the case in most houses. Hence copper is rarely deficient, but zinc, which is often at very low levels in most people's diets is further reduced by the presence of copper. It is rare to need to supplement it, but if zinc is supplemented over a long period it is sensible to use a supplement that contains a small amount of copper to balance it.

Soil levels of copper do vary and it is possible to become deficient if eating most of one's vegetables from a single copper deficient source, and not eating any meats.

Molybdenum

The human daily requirements for this mineral are unknown at present. However it is known that molybdenum is essential as part of some respiratory chain enzymes and therefore for the production of energy. It is also part of enzymes that are involved in breaking down cell proteins. It is known that deficiency can be a factor in dental caries, cancer of the stomach and oesophagus, impotence in middle aged men, and excessive growth in teenagers. The effect on growth is related to a molybdenum/ copper antagonism very similar to the zinc/copper antagonism. Copper promotes growth and molybdenum depresses it. The excessive growth which results from high copper levels can lead to structural problems in bones and the skeleton.

The best food sources of molybdenum are liver, unrefined wholegrain cereals, seeds, pulses, tofu and seaweed. These are not foods commonly included in the normal British diet and many people are deficient in this mineral. Coupled with the fact that high copper levels decrease molybdenum absorption, it is possible that most people are deficient.

Plants need molybdenum to 'fix' nitrogen from the atmosphere, which is probably why it is found in pulses which are known to be nitrogen fixers.

Some of the rest of the iron present in the body is in the form of enzymes. These are important substances that facilitate other biochemical reactions. Iron-bearing enzymes are required for energy producing processes in muscles and so without it our muscles do not have the energy they need to work and quickly become tired. The symptoms of anaemia are tiredness, breathlessness, giddiness, dim vision, headaches, insomnia, palpitations, fast pulse, heart murmurs, loss of appetite, indigestion and a tingling of the ‘pins and needles’ type in the fingers and toes, pimples and boils. One of the tell-tale outward signs is paleness of colour of the inside of the lower eyelid when pulled down.

Food known to contain iron

Iron can be found in many foods but is especially rich in organ meats and egg yolks. However it is also found in high quantities in green leafy vegetables, pulses, and is especially high in parsley.

Symptoms associated with iron deficiency

Absorption of iron can be reduced by drinking tea and coffee with meals. The tannins in tea inhibit iron absorption and substances in coffee have a similar but lesser effect. It is best to drink these beverages about one hour before eating a meal.

Daily requirements

The requirement for iron for men and women is different because when women menstruate they lose iron in the blood. So men require about 8 mg per day and women require 18 mg per day. The average diet can supply the 8 mg without too much trouble but the average diet with plenty of junk food and processed foods does not give the 18 mg women need and so a huge number of women are anaemic to some degree.

Taking iron supplements is not ideal because a high intake of iron can cause a deficiency of zinc as they compete for absorption. By ensuring a high level of iron is naturally present in the diet one is also ensuring that there is zinc present too.

In order for iron to be well absorbed the body needs vitamin C, which is also present in vegetables, though more especially in fruits. So a good diet would consist of green leafy vegetables, pulses and fruit.

Other associated factors

Anaemia can have other causes than iron deficiency including folic acid deficiency and vitamin B 12 deficiency. If you suspect you are iron deficient or anaemic you should see your doctor for a blood test.

Magnesium has a partnership within the body with calcium, which is well known for being essential for healthy bones and teeth. However what is not well known is that for calcium to do its job it needs to have magnesium present too.

Magnesium is the second most abundant mineral inside cells after potassium, and its distribution across cell membranes is closely linked with calcium and phosphorus metabolism. The average human adult has 20 - 30g of magnesium, seventy per cent of which is -contained in teeth and bones; the remainder - the physiologically important component - is found mainly in the cells.

FUNCTION WITHIN THE BODY

Magnesium is essential for many metabolic processes, especially the cellular ’pumps’ which maintain the correct distribution of sodium, potassium and calcium across cell membranes. Magnesium deficiency is associated with muscle cramps, or in extreme cases, tetany - continuous cramps, especially of the hands and feet. Because magnesium is involved in so many enzyme systems a deficiency has widespread metabolic consequences.

DAILY REQUIREMENTS

The average daily intake of a healthy adult should be 400-800mg, but requirements can increase in certain circumstances, such as with high-protein, high-calcium, high-phosphorus, or high-vitamin D intakes.

This is really the crux of the problem for many people. Most chronic diseases have a magnesium deficiency element to them and it is often because people have been having a diet high in calcium rich foods such as dairy produce, meats and phosphorus-containing fizzy drinks. In such cases the calcium levels rise but cannot be utilised properly without magnesium and the calcium gets ‘dumped’ in strange places forming cysts, fibroids and bony growths. Diseases such as osteoporosis and arthritis are often due to this problem.

The answer is usually not to give extra calcium (as there is already enough in the body, it is just in the wrong places) and to give extra magnesium instead. At the same time it is important to change the diet to one of REDUCED dairy produce, meat and no fizzy drinks while increasing the amount of magnesium-rich foods.

FOOD SOURCES

Magnesium-rich foods include seaweeds; beans, especially soya beans and their products; whole-grains particularly buckwheat and cornmeal; nuts and seeds, especially almonds and sesame and leafy green vegetables (magnesium is a component of chlorophyll, so the greener the vegetables, the more magnesium there is).

SYMPTOMS ASSOCIATED WITH A DEFICIENCY

Symptoms of magnesium deficiency are:-

Loss of appetite, nausea, apathy, weakness and tiredness, numbness and tingling, confusion and disorientation, learning disability and memory impairment, vertigo, convulsions, epilepsy, muscle cramps, grimaces, jerks, tremors, flicking eyes, muscular incoordination, insomnia, hyperactivity, constipation, heart rhythm problems, hypoglycaemia, abnormal ECG, pre-menstrual symptoms. Magnesium deficiency is also implicated in high blood pressure, osteoporosis, kidney stones, diabetes, and joint problems.

If you think you have a magnesium deficiency and it does not respond to changing your diet to a more magnesium-rich one it would be advisable to see a nutritional therapist for specialist advice on supplementation.

Adults normally have an average of 10 to 20 mg (most of which is in bone, liver and kidney) present in their body. However its importance is not in proportion to its quantity because it has some roles as part of essential critical enzyme pathways. Enzymes are the body’s catalysts and without them chemical reactions in the body would not take place. Manganese enzymes are involved in energy production, bone formation, protein, fat and cholesterol metabolism.

A deficiency in manganese can result in abnormal bone and cartilage and disc degeneration due to inadequate cartilage formation in the disc. Other signs of manganese deficiency include impaired glucose tolerance, birth defects, growth retardation, reduced fertility, reduced brain function and inner-ear imbalance. It could also produce fatigue.

Severe deficiency produces convulsions, skipped heartbeats, weight loss, dermatitis and hair colour loss. Manganese is involved in the building and degrading of proteins and nucleic acid, biogenic amine metabolism and is necessary for RNA chain initiation. Manganese enzymes are necessary for utilisation of vitamin C and some of the B vitamins such as choline, biotin and thiamine.

Manganese is found in nuts, seeds, whole grain cereals and in green leafy vegetables. Parsley is an especially good source These are often the foods that are not present in great quantities in the average diet so many people are deficient. If you are growing your own vegetables you will be getting some manganese providing there is some in the soil. However if you are growing vegetables in an alkaline soil or soil that has lime on it there will be less manganese in the plants as it is not taken up very well in such conditions.

Manganese and zinc are antagonistic to each other as regards absorption so if you take a zinc supplement long term you may become manganese deficient. It is also mutually antagonistic with iron and calcium. Many of the minerals have antagonistic reactions which is why it is better to take a multivitamin and mineral supplement where the minerals are in balanced quantities. Foods tend to be naturally more balanced and so not a problem.

The recommended daily allowance is between 2.5 to 5 mg per day, but these figures are too low, and a better level is 10 to 20 mg/day. The toxicity of this element is low and toxic levels are unlikely to be reached by dietary means. Supplement levels are also well below toxic levels. If you have high blood pressure, be careful of taking a manganese supplement as its initial reaction can be to increase blood pressure before it starts to calm down again. It is a case of too much of a good thing! If you eat a diet rich in green vegetables, nuts and seeds you may have a sufficient intake as long as your digestion is good.

Most of the phosphate in a human body is present in the bones where along with calcium it helps to form the bones. It is also necessary for energy production, storage and release and so is needed and used by every cell in the body.

Although we need lots of phosphorus (about the same amount as calcium) to maintain health, there is so much in food that deficiency is rare. As it is used in food processing, the worse someone’s diet is, the more phosphate they are getting and excess phosphorus is far more likely to be a problem. Excessive phosphorus reduces the absorption of calcium and magnesium and can cause deficiency of these two minerals, leading to the possibility of osteoporosis. Soft drinks and fizzy drinks can contain high levels of phosphate and drinking a large quantity over a long period could decrease bone density.

Low blood levels of phosphate can be caused by alcoholism, antacid therapy for gastric ulcers, intravenous glucose, barbiturate therapy, pregnancy and a vitamin D deficiency. Symptoms are muscle weakness (though other problems can also cause this), anaemia and increased susceptibility to infection. You should see a doctor if you have these symptoms and any of the conditions applies to you.

If one eats a good healthy diet including some of the following nuts, wholegrain cereals, eggs, legumes, meat, poultry and fish one will have enough phosphorus but not too much.

There is no recommended daily intake in UK as it has not been necessary to stipulate one.

You can ensure that your soil has plenty of phosphorus just by putting compost on the soil.

This is a substance that protects the tissues of the body from the highly reactive and destructive chemical entities called "free radicals". These are initially highly activated forms of oxygen. They can react with cell constituents converting them into damaged, non-functional materials, which may be toxic. The body has developed defence mechanisms against these free radicals, which are known as antioxidants. Selenium plays a role as part of a molecule called glutathione peroxidase which reacts with free radicals and makes them safe. It is also part of another enzyme group call the cytochromes P450 which are found in the liver where they are important for detoxification and elimination. There is a strong suggestion that it is also part of an enzyme that inactivates a cancer causing substance sometimes produced in our bodies. Selenium also seems to act to stop undue proliferation of cells which is inherent in the growth of cancer. It seems to prevent chromosome damage and poisoning with heavy metals.

Selenium is known as the silent protector because you only know that it is deficient when levels have gone so low that chronic diseases such as cancer, arterial disease and arthritis are triggered. There are no early warning signs.

Selenium works best in conjunction with vitamin E and so it is important to ensure that it is also present in the diet. It is found in nuts, seeds, soya, lettuce, eggs and good quality vegetable oils.

Although selenium is very important we only need it in small quantities. About 100 to 150 mcg per day. However, many of us do not get this amount and this is largely due to the variation of concentration in different soils. Soil in Europe, especially Finland, parts of north America, New Zealand and China all have low levels of selenium. Much work has been done in Finland where in some parts the soil is chronically depleted and there are very high rates of cancer and heart disease. Plants will grow quite well in depleted soils and not suffer so there has been little incentive to add selenium to fertilisers, and as a consequence many foods are very low in it. Foods that tend to have higher levels are whole grains, cereals, nuts, sea foods and organ meats.

Although selenium is essential for good health, too much is a bad thing and where soil levels are high, people suffer from selenium toxicity. A few plants thrive on toxic seleniferous soils and are recognised as 'indicator' plants because they accumulate quantities of selenium that are toxic to animals eating them. An example is the purple milk-vetch (Astragalus).

This issue covers 2 minerals whose actions are very dependant on each other, and where keeping a balance between them is crucial to life processes.

Sodium is the main mineral in all the fluids of the body outside the cells. Effectively the extra cellular fluid or plasma is a saline solution with other minerals and chemicals dissolved in it.

However inside cells the sodium level is very low and potassium is in high concentration. Sodium and potassium are very similar substances chemically and have similar properties.

All minerals dissolved in water will try to even out their distribution so that they are randomly and uniformly distributed throughout the fluid. Sodium will move into cells across the cell membrane as part of this action. Potassium will also diffuse down its concentration gradient out of the cell into the fluid. To maintain the concentrations of potassium inside the cells and sodium outside it cells have pumps to pump the two minerals back where they came from. The movement of these two minerals also drives other substances across the cell membranes so keeping the cell ‘fed’ with nutrients and ‘clean’ of cell rubbish. It is vital that these concentrations are maintained. There should be a ratio of 1 sodium atom to 7 potassium atoms throughout the body to maintain the balance.

We lose both minerals in urine, sweat, faeces, and with vomiting and they need to be replaced through our diet. Overall we need more potassium than sodium and our diets should reflect this. Early ‘stone age’ diets were very high in plant food which contains lots of potassium and not so much sodium. This is due to the fact that soils generally have high levels of potassium but very low levels of sodium. Meats have high potassium levels too, but sodium in the form of salt was rare unless the people lived by the sea. Our bodies have not developed a great deal since that time so we have good ways of preventing sodium loss but not of preventing potassium loss. We also have processes which allow us to get rid of excess potassium but not to get rid of excess sodium Now our diets tend to be high in sodium and low in potassium, the exact opposite of how they should be, ( especially as many people eat few fruits and vegetables), and so we are becoming increasingly sodiumised. This increase in sodium in tissues as well as low levels of potassium is one of the root causes of chronic illness. This is because many of the bodies metabolic processes rely on the different concentrations of sodium and potassium. Too much sodium in the body leads to sodium concentrations in the cells being too high which leads to high acidity and breakdown of cellular metabolism.

Hypertension is also a direct result of too much salt. This is because the body hangs on to excess water to dilute the sodium, swelling body fluids and producing high blood pressure. Hence reducing salt in the diet can lower blood pressure.

So how much sodium and potassium do we need?

There are no recommended daily allowances (RDA’s) for these two minerals. However 500 mg or less of sodium is adequate and about 3500 mg of potassium is ideal. This maintains the 1:7 ratio of sodium to potassium. The diet of the average US citizen is estimated to be about 7,500 mg of salt per day which equates to about 52,500 mg of sodium which is far too much. As well as being high in sodium, the ratio with potassium will not be healthy and potassium may even be deficient. It is likely that the British diet has a similar amount of sodium in it as it is added to most processed and prepared food. One can get an adequate amount of sodium just by eating natural foods without adding any extra salt. One can also get optimum amounts of potassium just by eating a diet of natural home prepared fresh vegetables, grains, meats, fruits and nuts. Fruits and vegetables are especially rich in potassium.

What about cramps?

People often think that the cramps they suffer from is due to sodium deficiency or lack of salt. This is mostly not true. Cramps do occur with sodium deficiency but only after severe prolonged sweating or vomiting when there has been a sudden loss of bodily fluids. Cramps are usually due to deficiency in magnesium, the mineral which helps muscles to relax after contraction.

So to keep healthy, eat lots of different types of vegetables and fruits, some natural proteins such as meat, pulses and nuts, and avoid salt and processed foods.

Cobalt

The first, cobalt, has a role in human health as part of vitamin B12, otherwise known as cyanocobalamine. The metal forms a central part of the molecule and without this mineral we would have pernicious anaemia, as it is vital for the formation of healthy red blood vessels. We receive most of our vitamin B12 from animal products, and vegans are known to be at risk of pernicious anaemia. However it is less well known that friendly bacteria, which should live in our guts (in the absence of anti-biotics), can produce vitamin B12 from the plant food we eat. More recent research shows that levels of cobalt are low in the hair samples taken from violent offenders, so it’s likely that there is a link with brain metabolism too.

Nickel

Nickel acts as an anti-dote to the blood-pressure raising action of adrenaline, which constricts blood vessels and stimulates the heart. Although nickel is found in soil, our greatest exposure is to the metal in everyday objects. As well as jewellery and coins, nickel is also found in car keys, pocket knives, metal spectacle frames, hooks and eyes, zips, scissors and many other household items. Some people develop a sensitivity to nickel and have to stop wearing anything containing it. Such people also have an increased tendency to food allergies. So it would seem that with nickel, as with most things, a little does you good but too much is bad for you. People are unlikely to have a nickel deficiency as it is present in our environment to such a large degree.

Boron has only recently been discovered to have a role in human health. It is needed for healthy bone metabolism and in areas where there is boron deficiency in the soil, osteoporosis is more prevalent. It interacts with calcium, magnesium and vitamin D to make strong bones, and is necessary for growth too. Boron is found in dark green leafy vegetables, fruit, legumes and nuts, depending on soil levels.

Vanadium

Vanadium is probably a trace element for man and may be of value in protecting against heart disease and cancer. Much has yet to be learnt about vanadium, whose biochemistry is very complex. It has been found that vanadium deficiency results in increased blood cholesterol and triglyceride levels. It also has insulin-like effects and so helps to regulate blood sugar.

Silicon is actually present in very large quantities in some soils as many rocks have silicon as one of their constituents. It is very similar to carbon in behaviour and structure, but forms stronger bonds. So, structurally strong tissues such as arteries, tendons, skin, collagen, connective tissue, and cornea contain large amounts of silicon, whereas other tissues such as liver, kidney and blood contain very little. Deficiencies can occur if one eats a lot of food from silicon deficient soil. It is found in high fibre foods, grain husks, nettles, alfalfa and flaxseed

Flourine

Fluorine is present throughout the body and is best known for its ability to reduce tooth decay. It also seems to be important in the maintenance of normal bone structure. However too much fluorine and in the wrong form is bad for us. It can cause mottling of teeth and some studies have linked it to birth defects and cancer. Fluorine that is naturally present in water is in a different form from that artificially added to the water, which is usually aluminium hexafluoride, and does not seem to have the same detrimental effects. Fluorine is found in quite reasonable amounts in tea and people who drink a lot of tea and live in a fluoridated area may be consuming too much.

To conclude, there are many trace elements which we do not know much about, including others not mentioned here. Further research is necessary both on soils and on the impact of deficiencies to human health. As always there can be deficiencies and excesses, both of which are detrimental to health.

The way to ensure a good supply of all trace minerals is to have a very wide variety of foods, preferably grown in different places to ensure that deficiencies in one type of soil are compensated for in another. It is fine if you grow your own vegetables, as long as you buy in grains, seeds, nuts and/or animal products from different places too. Composting is very important to ensure minerals are returned to the soil for recycling.

For many centuries Oysters have been thought of as aphrodisiacs. While some people may think this is an 'old wives tale' there is some reason for it. Oysters contain some of the largest concentrations of zinc found in any food. Zinc is required for proper functioning of the male sexual organs. Hence zinc, and therefore oysters. will help men ‘perform’ but the response time is rather longer than a couple of hours. A man would need to eat oysters for several days to feel a noticeable effect! An increasingly common symptom of zinc deficiency in older men is an enlarged prostrate. This uncomfortable and embarrassing complaint can be helped by correcting any deficiency of zinc

Another complaint that often responds to zinc supplementation is that of poor digestion. The stomach needs zinc to produce secretions which are used to digest food. If there is not enough zinc in the body then the secretions will not be in sufficient amounts to digest food properly which results in bloating and cramps after food. In particular, a person may well feel more uncomfortable after a meat meal.

Other problems that are caused by zinc deficiency are lack of energy, anaemia, increased blood pressure, lack of. growth, depression and schizophrenia. People with blood group A seem to be particularly prone to zinc deficiency as they appear to have problems absorbing it. If you are blood group A make sure you have adequate zinc in your diet.

How do we prevent these problems and avoid becoming zinc deficient?

Ultimately we aquire zinc through our diet. Plants are the medium for this as they draw the zinc out of the ground. However, if the soil becomes depleted in zinc or we lose the biological mechanisms that help feed the plant then they will still grow but the amount in our diet will be less. If soil is fertilised with compost and the structure of the soil biology is maintained then we can expect to see zinc levels increase.

Some foods hinder the absorption of zinc and these include coffee, cow's milk, cheese, hamburgers and bran. Some foods are very rich in zinc. We have already mentioned oysters which are the richest (they absorb zinc from the sea), then in descending order; ginger root, muscle meats, pecan nuts, split . peas, brazil nuts, egg yolk, wholewheat, rye, oats, peanuts, lima beans, almonds, walnuts, chicken, buckwheat, hazelnuts, clams, green peas, shrimps, turnips, parsley, potatoes, garlic, carrots, beans, corn. Try to ensure that you eat at least one or two of these foods daily.