Iron is a mineral responsible for the production of hemoglobin and the transfer of oxygen through the body. Iron is contained in animal- and plant-based foods. People who have an iron deficiency may have to take iron supplements to increase their iron levels in addition to eating iron-rich foods. Iron supplements and multivitamins that contain iron may cause stomach pain in some people.
Multivitamin Side Effects
Multivitamins contain several vitamins and minerals, often including iron. When taking multivitamins, some people may experience stomach upset or headaches. Taking an iron supplement in addition to a multivitamin may cause stomach pain, nausea or constipation. Constipation may also cause stomach pains.
Prenatal Vitamin Side Effects
Prenatal vitamins contain the same vitamins and minerals as a daily multivitamins; however, the recommended daily allowance of certain vitamins may increase during pregnancy. There is an increased need for iron intake during pregnancy, so prenatal vitamins contain more iron than do regular multivitamins. Women who take prenatal vitamins may experience symptoms such as stomach upset, nausea, headache or stomach pains.
Warning Signs
Do not take more than the recommended amount of multivitamins that contain iron. Taking iron in excess may lead to iron poisoning, which in some cases can be fatal. If you take more than one supplement that contains iron within a 24-hour period and you experience symptoms such as headache, nausea, extreme stomach pain or dizziness, get emergency treatment immediately.
Considerations
Any form of multivitamin, including prenatal vitamins that contain iron, is best absorbed when taken on an empty stomach, according to the Drugs website. If you experience stomach pains or nausea while using these products, take the supplement with food or with a glass of juice.
