Tea and coffee may reduce the body's absorption of iron, while alcohol and certain supplements can increase it. Iron overload happens when iron builds up in the body over time, potentially causing serious health issues. Excess iron can accumulate in organs like the liver, heart, and pancreas, leading to liver scarring, heart weakness, and impaired blood sugar control, which can result in diabetes. In a recent scoping review, researchers looked at 40 sources, including 38 peer-reviewed studies and two grey literature sources, to examine how food, drinks, and supplements affect iron absorption. Their findings suggest that diet can complement medical treatments by influencing how much iron the body absorbs. However, the effectiveness of dietary changes depends on the underlying cause of the iron overload. Inherited iron overload, known as "primary" overload, is most commonly caused by a condition called hereditary haemochromatosis, which is particularly prevalent among people of northern European descent. This condition causes the body to absorb too much iron from food. The standard treatment involves regular blood removal, known as venesection or phlebotomy. In contrast, "secondary" iron overload results from illnesses or treatments, such as repeated blood transfusions. These transfusions introduce iron that the body cannot effectively remove, and treatment often involves iron chelators—medicines that bind to iron to help the body eliminate it through urine or stools. This type of overload is common in people with thalassaemia, a group of inherited disorders affecting hemoglobin, the protein in red blood cells that carries oxygen. Tea contains polyphenols—plant compounds that mainly bind to non-haem iron, the form found in plant-based foods and fortified products. This binding makes the iron harder for the body to absorb. A small clinical trial involving 18 people with hereditary haemochromatosis found that drinking black tea with meals reduced iron absorption. However, the difference between the tea-drinking group and the water-drinking group was not statistically significant, meaning the results could have been due to chance. A later study tested extracts of black tea, cocoa, and grape juice, finding that the supplement reduced non-haem iron absorption by about 40% during a single meal. However, this study only measured the immediate effect and did not assess whether the supplement reduced long-term iron accumulation or treatment needs. Coffee also contains polyphenols that can reduce non-haem iron absorption when consumed with meals. However, evidence supporting its effectiveness in people with iron overload is less strong compared to tea. Haem iron, found in meat, poultry, and fish, is absorbed more readily than non-haem iron. People with hereditary haemochromatosis are often advised to limit red meat and particularly iron-rich offal like liver, while still maintaining a balanced diet. They are also generally advised to avoid iron supplements and multivitamins containing iron unless prescribed by a doctor. In the UK, people with haemochromatosis are advised to avoid breakfast cereals fortified with iron. Vitamin C increases the absorption of non-haem iron, so people with hereditary haemochromatosis are usually advised to avoid vitamin C supplements. However, they can still consume fruits and vegetables containing vitamin C. For people with transfusion-dependent beta-thalassaemia, medical guidelines may allow small, prescribed doses of vitamin C if a deficiency is confirmed. Unsupervised supplements can increase harmful forms of iron in the blood. Alcohol is a particular concern because it and excess iron can both damage the liver. A study of 206 people with hereditary haemochromatosis found that 61% of those consuming at least 60g of pure alcohol daily had severe, permanent liver scarring, compared to 7% of those consuming less. UK guidance recommends that people who drink regularly should not exceed 14 units of alcohol per week. Those with liver damage may be advised to avoid alcohol altogether. People with hereditary haemochromatosis are also advised to avoid raw or undercooked shellfish, such as oysters and clams, which can carry Vibrio bacteria and cause severe infections in people with iron overload. The evidence does not support a single "iron overload diet" because the scoping review mapped available research without formally rating each source's quality or combining results. Most studies were small and short-term, focusing on immediate effects rather than long-term health outcomes. Therefore, dietary changes may help manage iron absorption but cannot reliably replace medical treatment. Current guidance for people with hereditary haemochromatosis includes avoiding unprescribed iron or vitamin C supplements, limiting alcohol and frequent red meat consumption, and possibly drinking tea or coffee with meals to reduce non-haem iron absorption. People with transfusion-related iron overload need personalized advice that considers their treatment and any vitamin or mineral deficiencies. Anyone diagnosed with iron overload should consult their doctor or a specialist dietitian about dietary changes and supplements. While diet can support treatment, it cannot safely replace it.