Iron Supplement Problems

According to the National Institutes of Health, three groups of people are most likely to benefit from taking an iron supplement: those with a greater need for iron, those who lose more iron and those who have a problem absorbing iron normally. These groups typically include pregnant women, preemies, toddlers, teenage girls, women in their childbearing years, people who have kidney problems and those with gastrointestinal disorders. High doses of iron supplements, and taking the wrong kind of iron, can cause serious problems, however. It's always best to have your doctor advise you on the type of iron you should take and the proper amount.

Stomach Upset and Changes in Stool

Your doctor will generally only advise you to take iron supplements when you can't get the required amount of iron your body needs in a reasonable amount of time through diet alone. In regular use, iron supplements can cause serious, sometimes painful gastrointestinal upset. For example, you may experience constipation, nausea, vomiting and diarrhea. These symptoms are more pronounced if you take your supplement on an empty stomach. In addition, iron supplements can make your stools appear darker, even black. Though disturbing to look at, if you are following your doctor's advice, this is not a symptom to worry about. If you take an iron supplement in liquid form, it can also temporarily stain your teeth, but diluting it helps.

Interaction with Calcium and Other Nutrients

Taking your iron supplement with a meal that contains calcium can reduce how much iron you will absorb, according to the Linus Pauling Institute. Calcium supplements also shouldn't be taken at the same time as iron supplements for the same reason. In addition, the institute reports soy protein, such as tofu, may have a similar effect in reducing iron absorption.

Iron Overload and Toxicity

Because little iron is excreted from the body, with supplementation, iron can accumulate in your body, according to The National Institute of Health. You mostly lose iron when you lose blood. When your normal iron storage sites are full, iron can accumulate in tissues and organs. This is yet another reason why taking iron supplements should only happen under the direction of your health care provider. Too much iron accumulation can be toxic. According to Colorado State University Extension, as little as 20 to 60 mg of iron per kilogram of body weight can cause death. According to the Linus Pauling Institute, accidental overdose of iron-containing products is the biggest cause of poisoning fatalities in children younger than age 6. Iron overdose is a serious problem that requires emergency care.

Other Health Problems

Some people are born with conditions, such as hemochromatosis, which makes them very efficient at absorbing iron. With a condition like this, taking an iron supplement can lead to iron overload. Moreover, if you have a blood disorder, or require frequent transfusion, you are also more susceptible to iron overload, making supplementation dangerous. If your supplementation causes an overload, you may begin experiencing abdominal pain, rapid pulse, low blood pressure and difficulty breathing. It can also induce a coma. The Linus Pauling Institute reports that if it's not immediately fatal, symptoms may go away only to return some hours after you take iron again, bringing along failures to your kidneys, liver, blood and central nervous system.