Iron willed

Dietary supplements serve a valuable purpose but beware of the side-effects. Dr John Briffa spells out the risks

One nutrient that has managed to establish itself firmly in mainstream medical practice is iron. Even doctors who view nutritional supplements with some scepticism are generally comfortable about firing off prescriptions for this blood-building mineral. Yet, while iron undoubtedly has the ability to do much good in the body, taking it is not without risk: iron therapy often gives rise to tummy trouble and might increase the risk of certain conditions such as heart disease.

Iron is essential for the manufacture of haemoglobin. Contained within the red blood cells, haemoglobin transports oxygen to the tissues, where it sparks life into the body's metabolic processes. If haemoglobin levels become low - the medical term for which is anaemia - fatigue, reduced capacity for exercise and low moods are often the result. Anaemia can be caused by many underlying factors, but iron deficiency is the most common.

Iron is also an essential ingredient in the production of adenosine triphosphate (ATP) - the basic currency of energy in the body. Because of this, iron deficiency can sap vital energy, even in the absence of anaemia. This is more common in vegetarians, during pregnancy and in women prone to heavy periods, as significant quantities of iron are lost in the menstrual blood.

Although popular in the form of a tonic and energy booster, iron does need to be handled with care. It is an oxidising agent, having the opposite effect of antioxidant nutrients such as vitamins C and E, which have disease-protective properties. Japanese research published last year suggested that high doses of iron induced changes which, at least theoretically, could increase the risk of heart disease.

This study supports previous evidence of increased risk of heart disease in Finnish men with high levels of iron in their bodies. To my mind, those considering taking an iron supplement should make sure they really do need it first.

The conventional way of determining iron levels in the body is with blood tests. The most useful test is to measure the level of a substance called ferritin. When levels are low, increased iron intake is quite likely to improve energy and well-being.

The most absorbable form of iron in the diet is found in animal products such as red meat, oysters and fish. For vegetarians, sources of iron include dried fruit, molasses and green leafy vegetables.

Iron is available over the counter and on prescription. A commonly prescribed form is ferrous sulphate, though this can cause constipation. Other forms include ferrous gluconate and ferrous succinate. Vitamin C enhances the absorption of iron, and taking 250-500mg with each dose can help prevent unwanted side-effects, too.

Dear John

My three-year- old son suffers from constipation. I encourage him to eat plenty of fruit and vegetables, but with limited success. The doctors can find nothing wrong. Do you have any advice?
Pauline Moore, Aberystwyth

There are many causes of constipation in children, and persistent cases do require a medical opinion. However, many will resolve with a simple, dietary approach. I appreciate that it is not easy to get children to eat fruit and vegetables, so why not try this? If you have a blender, make your son a fruit smoothie (eg banana and strawberry) each day - most children will quite happily drink blended soft fruit passed off as regular fruit juice.

The other essential ingredient in relieving constipation is fluid, so make sure your son drinks plenty.

An important factor in childhood constipation is milk. One study found that excluding it from the diets of children with severe long-term constipation (one motion every three to 15 days) led to a normal bowel habit in most cases. Try your son on a milk-free diet to see if this helps. Soya and rice-based milks make good alternatives to cow's milk and are widely available.

Nutrition news

Eczema is a common condition characterised by reddening and scaling of the skin. Conventional treatment uses steroid creams. Yet while these may help to dampen down the inflammation believed to be at the root of the condition, they do not generally bring long-term relief and may permanently damage the skin.

A recent study examined whether the skin-healing nutrient vitamin E might be of value in treating eczema. Researchers gave eczema sufferers aged between 10 and 60 400IU of vitamin E or placebo (inactive medication) each day for eight months. Sixty per cent of those taking vitamin E reported a great improvement in their eczema, compared with just 2 per cent of those taking the placebo. This suggests that long-term use of vitamin E may provide effective relief for many eczema sufferers.

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Leading nutritionist Dr John Briffa reveals the recipe for good health