Iron overload is usually not caused by eating too many iron-rich foods. Instead, it is triggered by a combination of factors: first, a genetic prosperity and, second, years of overdoses of iron from repeated blood transfusion or iron supplementation.

The body stores iron in the liver. The danger is, if levels go too high, they can overload and harm the liver, conditions referred to as hemosiderosis (iron overload) and hemochromatosis (overload to the point of damage). Symptoms of these disorders include bronzing of the skin, diabetes, enlarged heart, heart arrhythmias, loss of libido, abdominal pain, and arthritis. Hemosiderosis used to be quite rare, but in recent years, scientists have found that it is increasingly prevalent ad that cases may be aggravated by iron supplementation.

Not everyone is susceptible to iron overload. People have different abilities to absorb iron. Caucasians of Northern European extraction may be the most susceptible. A small but significant number of them carry a gene that allows for absorption of too much iron. Early studies had indicated that this tendency was quite rare, but now it is estimated that about 2 to 3 per 1000 people in the United States may carry this genetic susceptibility. Up to 10 percent of Caucasians of Northern European extraction are at risk.