We need iron to live. Without it, our red blood cells wouldn’t be able to carry oxygen through our blood. Iron plays essential roles in energy metabolism, hormone synthesis, growth, development, brain function, immune activity, and cellular function.[1, 2] However, you only need trace amounts of this important nutrient to maintain proper iron balance. Excess iron intake can quickly become dangerous.
Iron toxicity is an overdose caused by ingesting too much iron. It can be either gradual or acute. Acute iron poisoning is very dangerous and requires immediate action.
What Is Iron Poisoning?
The term “iron poisoning” generally refers to a sudden, acute iron overdose rather than a slow, gradual buildup of iron. It usually occurs when a person greatly exceeds the recommended dosage of iron pills. Excessive iron is corrosive to the digestive system, making the symptoms traumatic and hard to miss. The symptoms of iron poisoning come in several distinct stages.
Stage 1: This stage occurs in the first six hours after ingestion. Initial symptoms of iron poisoning include abdominal pain, nausea, drowsiness, diarrhea, and bloody vomiting. Continuous vomiting may cause dehydration. In more extreme cases the patient may lose consciousness or lapse into a coma.
Stage 2: The second stage typically lasts a day or two. In this stage, symptoms seem to improve. Many people assume this means that the danger has passed, but this is still a very dangerous time. The initial symptoms appear to ease because the iron has moved from the digestive system. However, it is now in the bloodstream, where it can do even more damage.
Stage 3: Over the course of the next few days, iron will circulate throughout the body, slowly damaging organs and tissues. This leads to seizures, shock, internal bleeding, severe liver damage, and dangerously low blood pressure, any of which could be fatal.
When to Seek Help for Iron Poisoning
If you suspect that yourself or a loved one are currently experiencing acute iron poisoning, call your local poison control center immediately! If you’re anywhere in the United States, you can dial 1-800-222-1222 to contact the free poison helpline. Operated by the U.S. Department of Health and Human Services, this national helpline is available 24 hours a day, seven days a week, 365 days a year.
While anyone can suffer from acute iron overload, children are particularly vulnerable. The FDA requires that all iron supplements include the following warning directly on the label:
“WARNING: Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6. Keep this product out of reach of children. In the case of accidental overdose, call a doctor or poison control center immediately."
Iron pills often take the form of small, bright red disks that could be mistaken for candy by a curious child. Take steps to make sure that children can’t get a hold of your iron supplements.
- Use child-resistant containers, but remember that there is no such thing as “child-proof.” Given time, a sufficiently determined child can get into anything. A child-resistant container should slow them down, but don't rely on it as your sole means of deterrence.
- Keep all vitamins and supplements out of the reach and sight of children. Like child resistant containers, this is just one precaution, not a complete solution. Children can and will climb on anything. Putting your pills on a tall shelf doesn’t mean that they’re entirely out of reach. If possible, keep your supplements in a locked cabinet.
- Make sure that all purses and bags that contain vitamins and supplements are also out of a child’s reach. This includes any guests' bags as well.
- Never put disposed-of medications in an open trash container where children can reach them.
- Be aware of all medications, vitamins, and supplements in your own home, and any home where your child spends time, like grandma’s or a friend’s house.
Iron Poisoning in Pets
Like children, pets also have a habit of eating things they shouldn’t. The symptoms of iron poisoning in dogs are very similar to that of humans — vomiting, bloody diarrhea, lethargy, and abdominal pain. Symptoms can progress to tremors, cardiac distress, liver damage, and severe shock.
You can keep pets safe from iron poisoning by following the same precautions you would with children. Keep your supplements well out of the reach of your furry family members. Some pets seem to regard the garbage can as a type of buffet, so be extra aware of what goes in the trash. Iron can also be found in chemical hand warmers, fertilizers, and oxygen absorbers (those little “do not eat” packets found in some prepackaged foods and consumer goods). Be sure to keep these items away from pets.
What Is Gradual Iron Toxicity?
Slow, chronic iron toxicity is usually referred to as iron overload disease, ferrotoxicity, or iron buildup. While not as immediately life-threatening as acute iron poisoning, it nonetheless carries its own severe health risks.
Once absorbed, the human body doesn’t have a mechanism for getting rid of excess iron. While trace amounts of iron are lost through urination and excretion, you mostly lose iron only when you lose blood. This includes menstruation, which is one reason why women have higher iron needs than men. Excess iron damages your organs and tissues and increases oxidative stress throughout your body.
What Is Hemochromatosis?
Hemochromatosis is a hereditary condition that can exacerbate iron toxicity. Normally, a liver hormone called hepcidin regulates the absorption, use, and storage of iron in the body. In those with hemochromatosis, a genetic mutation disrupts hepcidin, causing the body to absorb iron indiscriminately, regardless of iron status. It can increase the risk of joint issues, diabetes, liver damage, coronary issues, and reproductive abnormalities.
Hemochromatosis most heavily affects people of European descent; approximately one in 10 are potential carriers of the gene that causes this disorder. Most people who carry this gene are asymptomatic, but the condition is active in about four out of every 1000. Hemochromatosis is far less common in other ethnic groups. If you have hemochromatosis, avoid iron supplements and monitor your intake of Vitamin C.
Does Iron Interact With Other Supplements or Medications?
High-dose iron supplements can react poorly with many types of medication. Possible interactions can occur with thyroid replacement hormones, birth control, antibiotics, blood pressure medication, and prescriptions that treat ulcers and other stomach issues. Check with a healthcare professional before starting iron supplements if you take any kind of medication, vitamins, or supplements.
There are two main types of dietary iron — heme and nonheme. Heme iron comes from animal sources, while nonheme comes from plants. Heme iron is absorbed by the body more quickly, so it is often mistakenly thought that vegans and vegetarians are more at risk for iron deficiency. Research, however, has found that those who follow a plant-based diet are no more likely to suffer from iron deficiency anemia than anybody else.
In fact, nonheme iron provides a safer and more stable iron absorption rate. Nonheme iron is associated with significantly lower rates of metabolic syndrome, heart disease, diabetes, stroke, and cancer than its meat-based counterpart. For every milligram of heme iron you consume, your risk of heart disease increases by 27%. The cancer risk also increases significantly.
This may be because iron acts as an oxidant in the human body, adding to your free radical load and causing oxidative damage. Nonheme iron is often found in foods that contain potent antioxidants, like vitamin C. These antioxidants inhibit oxidation and terminate the chain reactions that produce free radicals.
Find the Right Balance
Iron is a double-edged sword. If your iron levels are low, you may face the health risks of iron deficiency anemia; too high, and you’ll have to deal with acute or chronic iron toxicity. Ultimately, like many things in health and life, iron is all about finding the right balance. Try getting your iron from food sources instead of pills; this reduces the risk of overdose drastically. Food, particularly plant-based food, is the safest way to incorporate iron into your diet. Fortunately, there are plenty of excellent, plant-based, iron-rich foods.
Supplementation may be beneficial in some cases, such as iron deficiency anemia or during pregnancy. If you do supplement with iron, I advise caution. Some people approach supplements with the assumption that "if some is good, then more must be better." This is a reckless attitude that can have serious, possibly dangerous, health consequences. Consult your trusted health care advisor before taking an iron supplement, and take only as directed.
Never give iron supplements to a child unless under the supervision of a health care professional. A healthy adult should only need between 18 and 27 mg of iron each day. Pregnant women should aim for somewhere between 27 and 45 mg total. Except in cases of extreme deficiency, iron doses higher than that are unwise and unhealthy.
If you choose supplementation, be sure to do your research. Avoid elemental iron supplements. I recommend a nonheme supplement with no more than 18 mg of iron per serving.
Have you had an experience with iron toxicity? How do you make sure you have the right iron balance? Let us know in the comments!
- "Dietary Supplement Fact Sheet: Iron." National Institutes of Health. U.S. Department of Health and Human Services, 11 Feb. 2016. Accessed 17 Apr. 2017.
- Higdon, Jane, Ph.D., et al. "Iron." Linus Pauling Institute Micronutrient Information Center. Oregon State University, May 2016. Web. 02 May 2017.
- Heller, Jacob L. "Iron Overdose." MedlinePlus Medical Encyclopedia. U.S. Department of Health & Human Services, 13 Oct. 2015. Web. 02 June 2017.
- Shander, A., M. D. Cappellini, and L. T. Goodnough. "Iron Overload and Toxicity: The Hidden Risk of Multiple Blood Transfusions." Vox Sanguinis 97.3 (2009): 185-97. Web. 2 June 2017.
- "Hemochromatosis." National Institute of Diabetes and Digestive and Kidney Diseases. U.S. Department of Health and Human Services, Mar. 2014. Web. 02 June 2017.
- "Possible Interactions With: Iron." University of Maryland Medical Center. University of Maryland Medical Center (UMMC), 14 May 2007. Web. 02 June 2017.
- "Iron in the Vegan Diet." The Vegetarian Resource Group (VRG), The Vegetarian Resource Group, Accessed 17 Apr. 2017.
- Hooda, Jagmohan, Ajit Shah, and Li Zhang. "Heme, an Essential Nutrient from Dietary Proteins, Critically Impacts Diverse Physiological and Pathological Processes." Nutrients 6.3 (2014): 1080–1102. PMC. Web. 2 June 2017.
†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.