In 1980, medical student Jerome Sullivan, now a pathologist at the Veterans Affairs Medical Centre in Charleston, South Carolina, noticed an apparent correlation between high iron levels (as ferritin) in the blood and increased risk of heart disease. Further research showed that iron levels were a better indicator of risk of heart disease than high cholesterol, but also that ingesting iron could lead to higher cholesterol levels.

Iron excess to requirements for making red blood cells is stored in the body. The only way it can be lowered is by losing blood, which women do through menstruation. Women's iron levels are consistently lower than those of men until after menopause, when women's average ferritin levels creep up to equal those of men. As their ferritin levels increase, their risk of heart disease also rises to match that of men.

Traditional heart specialists brought up on hypertension, smoking, cholesterol, inactivity, age and gender as causes of heart disease contested Jerome's hypotheses and the debate continues. Whilst the academics argue, it is simplicity itself to take control of your own health. A 'transferrin saturation blood test' is free on the NHS if you can persuade your GP to prescribe one, or around £32 privately if you cannot. Healthy levels of ferritin are:

• menstruating women: 12-40 milligrams/litre (mg/l)
• men and postmenopausal women: 70-150 mg/l

Ways to reduce iron/ferritin levels if necessary include: eating less red meat; avoiding iron supplements or breakfast cereals fortified with iron; giving blood. A Finnish study showed that giving blood four times a year can reduce ferritin levels to less than 50 mg/l in men, and down to 25 mg/l in women.

Ed.- Research funded by the then Ministry of Agriculture, Food and Fisheries (MAFF, now Defra) and confirmed by the British Institute of Food Research suggested that a high intake of iron in capsule form can stimulate the production of free radicals - the cells suspected of triggering cancer - and may increase people's risk of colon cancer. The research subjects took 100mg of iron in capsule form a day for two weeks. The researchers do not recommend stopping iron supplementation, but that a safe level needs to be established.

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