Can You Take Too Much Iron?
Unlike some supplements, when the subject is iron, more is definitely not better. Adults shouldn't take any more than 45 mg of iron a day unless they are being treated with iron under close medical supervision.
For children, iron overdose can be especially toxic. "Iron supplements have killed young children because their needs for iron compared to an adult's are relatively low," Thomas says. If you take iron supplements, it is very important to keep them in a high, locked cabinet, far out of your children's reach. Symptoms of iron poisoning include severe vomiting, diarrhea, abdominal pain, dehydration, and bloody stool in children.
It's difficult for adults to overdose on iron just from food and supplements, because an adult body has systems in place to regulate the amount of iron it absorbs. However, people with the inherited condition hemochromatosis have trouble regulating their iron absorption.
Although most people only absorb about 10% of the iron they consume, people with hemochromatosis absorb up to 30%. As a result, the iron in their body can build up to dangerous levels. That excess iron can deposit in organs such as the liver, heart, and pancreas, which can lead to conditions like cirrhosis, heart failure, and diabetes. For that reason, people with hemochromatosis should not take iron supplements.