Iron overload: How tea, coffee, red meat and alcohol can affect absorption

Iron overload, a condition where too much iron accumulates in the body, can lead to serious health issues affecting organs like the liver, heart, and pancreas. This can result in scarring of the liver, weakened heart function, and impaired blood sugar regulation, potentially leading to diabetes. Recent research suggests that dietary habits, including consumption of tea, coffee, red meat, and alcohol, may influence iron absorption in the body.

Hereditary hemochromatosis, the most common inherited form of iron overload, is characterized by excessive iron absorption from food. Treatment typically involves regular removal of blood, a procedure known as phlebotomy. Another form, transfusion-related iron overload, occurs when individuals repeatedly receive blood transfusions. Certain medical conditions, such as thalassemia, can also increase iron absorption from food.

Certain foods and drinks have been found to impact iron absorption. Tea, for example, contains polyphenols that bind to non-heme iron, reducing its absorption. A small clinical trial showed that drinking black tea with meals could reduce iron absorption in individuals with hereditary hemochromatosis. Coffee, too, contains polyphenols and can decrease non-heme iron absorption when consumed with meals. However, its effects may be more pronounced than those of tea.

Heme iron, found in meat, poultry, and fish, is more readily absorbed than non-heme iron, which is more prevalent in plant-based foods. Individuals with hereditary hemochromatosis may be advised to limit red meat intake, including iron-rich offal like liver, while still maintaining a balanced diet. Regular consumption of vitamin C-rich foods is generally discouraged for those with iron overload, as it can increase non-heme iron absorption. However, small doses may be permissible under medical supervision.

Alcohol consumption can exacerbate liver damage in individuals with iron overload. A study found that heavy alcohol consumption significantly increased the risk of severe, permanent liver scarring in those with hereditary hemochromatosis. UK guidelines recommend limiting alcohol intake to 14 units per week, and abstaining altogether for those with liver damage.

Other lifestyle factors, such as avoiding raw or undercooked shellfish and being cautious with supplements, are also advised for people with iron overload. The effects of dietary changes on iron overload are not uniform across all individuals or conditions, and further research is needed to establish clear guidelines. Current recommendations include avoiding unprescribed iron or vitamin C supplements, limiting alcohol intake, and moderating red meat consumption for those with hereditary hemochromatosis.