Iron supplements should be used cautiously, only when required, and in accordance with recommended doses. Prolonged use of iron supplements or an excess of iron in the system can lead to adverse side effects.
Iron supplements frequently result in gastrointestinal discomfort, including symptoms such as nausea, abdominal pain, dark stool, heartburn, and constipation, and other side effects such as headache. This can be a significant challenge for individuals with IDA, who may find it difficult to adhere to their treatment recommendations.[1]
Although ferritin, hemosiderin, and transferrin play essential roles in regulating iron levels in the system, an excessive amount of free iron can trigger the production of free radicals and increase oxidative stress. This can potentially lead to damage to proteins and cells, and harm the body.[2][3] Diseases characterized by iron overload include hemochromatosis, a hereditary disease in which iron builds up to toxic levels in the body, which can lead to damage to organs such as liver, joints pancreas or heart.[4]
Additionally, multiple observational studies have reported that regular consumption of dietary iron, especially heme iron sourced from meat products, may predispose one to numerous diseases (e.g., type 2 diabetes, cardiovascular disease, coronary heart disease) and may increase the risk of some cancers (e.g., breast, colorectal, and esophageal cancer). However, the majority of these claims are based on self-reported food diaries or food questionnaires, and the level of evidence is weak. Furthermore, it’s important to highlight that processed meat does not only contain heme iron, but other potentially harmful substances (e.g., nitrite, nitrate, heterocyclic amines) which may be confounding factors that also raise the risk of some diseases.[4]
In children, low doses of iron may cause diarrhea, but they do not appear to increase the risk of infections at the recommended dosage. Nevertheless, the World Health Organization (WHO) advises monitoring children in countries at high risk of malaria when receiving iron supplementation, as it may both increase the risk of contracting the disease and potentially worsen its effects. The mechanism by which iron interacts with malaria is still not fully understood.[1][5]