Your body needs iron to function properly, and a well-balanced diet should allow you to meet your needs. If your iron level gets too low, your physician may recommend iron supplements. All supplements can have side effects and it is best to discuss these with your physician before starting to take the supplement. Since there are many causes of unexplained weight gain, your doctor can run tests to determine if it is from the iron supplement or from another cause.
Iron's primary role is to help your body transport oxygen. However, it also must be present for your immune system to function correctly and it plays a role in cognitive development, regulating your body's temperature and energy metabolism, says the Ohio State University. Iron can be obtained through eating animal meats and many foods such as beans, breads, cereals and others are fortified with iron. A lack of iron can lead to many health problems, so if you are unable to get enough through your diet, your physician may recommend supplements. Iron supplements can cause side effects and too much iron in the body can be dangerous, so it is best to take supplements under medical supervision.
Everyone's sensitivity to iron varies, so your side effects may be different, more severe or less severe then someone else taking the same amount. The most common side effects of iron supplements are nausea, vomiting, constipation, diarrhea, dark colored stools and abdominal distress, notes the Office of Dietary Supplements. Less common side effects include muscle pain, dizziness, irregular heart rate and skin rashes. Weight gain is not a common side effect of iron supplements, but if you experience a change in weight while taking them, speak with a health-care provider.
High amounts of iron in the blood can lead to organ damage, including to the liver, heart, and pancreas. Most cases of iron overload are caused by underlying medical conditions, but it can also occur from taking large doses of iron, reports the National Woman's Health Information Center. A high level of iron in the body can cause many symptoms, including weight loss, fatigue, joint pain, palpitations and changes in skin color. Weight gain is usually not associated with too much iron in the blood.
The most common cause of weight gain is eating more calories than the body burns. However, in rare cases, sudden weight gain can be due to medical conditions such as a thyroid disorder, polycystic ovary syndrome, Cushing syndrome, heart disease or lung disease, according to MedlinePlus. There are also some medications that cause the body to retain fluid, which can lead to an increase in weight. A physician can run tests to determine what is contributing to your weight gain while taking iron supplements.