It is well known that people with a condition called hemochromatosis, where the body absorbs and accumulates unusually high amounts of iron, are at a greater risk of developing diabetes. Recent medical research however suggests that there may be a link between iron levels and diabetes even among people that do not suffer from hemochromatosis.

A 2004 study published in the American Medical Association involving over 32, 000 women found that those with high levels of iron in their bodies were as much as three times more likely to develop diabetes than women with low iron levels.

A separate 2006 study found that women with high intakes of a type of iron known as heme, found mainly in meat, had a 28% higher risk of type-2 diabetes than those with a low intake. The study found no association between intake of the non-heme variety of iron and diabetes. Sources rich in non-heme iron include tofu, soybeans, spinach, potatoes and cashew nuts.

A third Finnish study of over 1000 men aged between 42 and 60 found that men with high iron stores were 2.4 times more likely to get diabetes compared to men with lower stores.

The findings raise the possibility that a simple iron blood test could determine whether an individual is at an increased risk of developing diabetes.

It is thought that iron may raise diabetes risk by increasing free radical production which increases inflammation levels n the body, possibly damaging the pancreas which is responsible for insulin production. Another possibility is that high iron levels cause cells to gradually become resistant to insulin, thus reducing the ability of insulin to reduce blood sugar levels.

The research suggests that both men and women considered at risk of developing diabetes should avoid iron supplements and consider limiting red meat consumption to a maximum of 2-3 servings a week.

While iron is an essential mineral in the body and is needed to prevent anemia, excess iron has been linked to various other diseases in the past such as an increased risk of atherosclerosis and heart disease, liver damage, some forms of cancer and even Parkinson's disease.

The current recommended daily intake (RDA) for iron is 8 milligrams a day for men and post-menopausal women while the RDA for pre-menopausal women is 18 milligrams. According to the National Health and Nutrition Examination Survey, most men generally exceed the RDA for iron although some women consume slightly less than the RDA.