According to the NIH, it’s recommended that adults get no more than 45 mg of iron per day, though a doctor may prescribe a higher amount to people who have been diagnosed with an iron deficiency.
While iron is beneficial within normal ranges, it can have unpleasant or even severe effects at high levels.
Causes
“Iron overload typically happens from taking high amounts of iron supplements,” Gold Anzlovar says. For this reason, it’s important to consult a doctor before taking an iron supplement, and to take only the amount prescribed.
Iron toxicity can also be caused by hemochromatosis, a genetic condition that causes iron to build up in the body, according to the NIH. If left untreated, hemochromatosis can cause severe medical problems, including liver cirrhosis, liver cancer, and heart disease. These folks should steer clear of iron supplements and vitamin C supplements.
Signs and Symptoms
Iron can be dangerous in high amounts. According to MedlinePlus, overdosing on iron supplements can cause many symptoms, including:
- Vomiting (sometimes with blood)
- Diarrhea
- Nausea
- Low blood pressure
- Shock
- Coma
- Dizziness
- Fever
- Yellowing of the skin (jaundice)
- Flushing
- Convulsions
Some symptoms may go away in a few hours, but they will return again a day or so later. Seek emergency medical treatment if you notice any of these symptoms.
Consequences
In the short-term, high doses of iron can cause gastrointestinal (GI) symptoms, such as stomach upset, constipation, nausea, vomiting, abdominal pain, and diarrhea, per the NIH.
Over time, high doses of iron can reduce your body’s ability to absorb zinc, thereby increasing your risk of a zinc deficiency, says Gold Anzlovar. Zinc is another mineral, and it plays an important role in immune function, wound healing, and the creation of protein and DNA. Zinc deficiency can lead to loss of appetite, lowered immune function, weight loss, mental lethargy, delayed wound healing, diarrhea, and hair loss.
Taking in more iron than your body can absorb can also cause inflammation in the GI tract, which can lead to poor nutrient absorption, disruption to the gut microbiome (the bacteria and other microorganisms in your digestive tract), and greater inflammation elsewhere in the body, Bohnengel says. Any one of these scenarios could have long-term consequences for your health. Research suggests that chronic inflammation, for example, causes and worsens many common diseases, from cancer to heart disease to pancreatitis. Meanwhile, malabsorption can affect growth and development, or it can lead to specific illnesses, notes Johns Hopkins Medicine. Changes in the gut microbiome can also have negative effects, especially if the balance between helpful and potentially harmful bacteria gets thrown off. If that happens, you may face a greater risk of disease, according to Harvard Health.
At extremely high doses — in the hundreds or thousands of milligrams — iron can cause organ failure, convulsions, and death, notes the NIH.
Prevention
To avoid iron toxicity, don’t oversupplement. Be sure to work with your healthcare team before taking a supplement, and if they determine you need one, ask them what dosage you need to take. Getting your iron levels tested regularly via blood samples can also be helpful.
Treatment
Severe iron overdoses are typically treated at the emergency room. According to MedlinePlus, treatment may include:
- IV fluids
- Medicine that helps remove iron and treat symptoms (chelation)
- Endoscopy, when a camera and tube are run down the throat to view the esophagus and stomach and remove pills
- Whole bowel irrigation, in which iron is quickly flushed through the digestive system
- Breathing support
