What Happens if You Take Too Much Iron?
You need iron to form proteins and to form red blood cells that carry oxygen throughout your body. High levels of iron in the blood can be dangerous, so only take iron supplements if your doctor prescribes them. Although it is easy for children to take too many iron supplements, since they sometimes confuse these pills with candy, it isn’t common to get too much iron from foods unless you have a hereditary condition called hemochromatosis.
Iron is an essential mineral in the diet, and is a crucial component of hemoglobin, the protein in red blood cells that carries oxygen throughout the body. Dietary iron is present in two forms. Heme iron is bound within a ring-shaped molecule called porphyrin. It is found mainly in red meat. Non-heme iron is found in both plants and animals. Its absorption is aided by vitamin C.
The hormone hepcidin regulates the body’s balance of iron. The function of hepcidin is to suppress absorption of iron. When the body’s iron stores are high, levels of hepcidin increase, and iron absorption decreases. When iron stores are low, iron absorption increases. For this reason, it is uncommon to suffer from too much iron in the diet. However, there are some situations where iron toxicity or iron overload can occur.
Iron toxicity can be caused by taking high doses of iron supplements for prolonged periods of time, or by taking a single overdose. Single doses as low as 10 to 20 mg/kg can cause some symptoms of iron toxicity. Medical attention is required at doses greater than 40 mg/kg, and more than 60 mg/kg can be lethal.
Excessive iron can be damaging to the gastrointestinal system. Symptoms of iron toxicity include nausea, vomiting, diarrhea and stomach pain. Over time, iron can accumulate in the organs, and cause fatal damage to the liver or brain.
Toxic cellular effects occur as well. Oxidative phosphorylation and mitochondrial function can be hindered by large amounts of iron, leading to death of cells. Iron toxicity primarily affects the liver, but other organs and the blood may also be affected.
Metabolic acidosis occurs due to fluid loss, dilation of the blood vessels and an anaerobic metabolism due to inhibition of oxidative phosphorylation.
Iron overload is a condition that can develop over time, particularly in people who receive many red blood cell transfusions, such as patients with myelodysplastic syndrome, thalassemia, or sickle cell disease.
When the body absorbs too much iron and its iron-binding proteins are saturated, the result may be a disorder of iron overload, known as hemochromatosis. The illness causes a bronze tint to the skin. However, it also brings about more serious effects of the disorder on the organs. Deposits of iron in the liver can cause cirrhosis, while in the pancreas, it may lead to diabetes.
Hemochromatosis is a genetic disorder of iron metabolism. It does not result from excess iron intake by a genetically normal individual. People with hemochromatosis can reduce the risk of illness due to iron overload by reducing their intake of iron-rich foods like red meat, and donating blood frequently. They should also avoid using iron cookware, and should not combine foods high in vitamin C with foods rich in iron.
High iron levels have been shown to cause cancer in humans and animals. High levels of heme iron in the diet are associated with an increased risk of colon cancer. Heme iron may lead to formation of carcinogenic N-nitroso compounds in the digestive tract.
There are two reasons why iron levels are tightly regulated within the body:
- Iron is an essential nutrient that plays a role in many basic body functions, so we must get a small amount.
- High levels of iron are potentially toxic, so we should avoid getting too much.
The body regulates iron levels by adjusting the rate of iron absorption from the digestive tract.
Hepcidin, the body’s iron-regulatory hormone, is responsible for keeping iron stores in balance. Its main function is to suppress the absorption of iron.
Basically, this is how it works;
- High iron stores -> Levels of hepcidin increase -> Iron absorption decreases.
- Low iron stores -> Levels of hepcidin decrease -> Iron absorption increases.
Most of the time, this system works quite well. However, a few disorders that suppress hepcidin production can lead to iron overload.
On the other hand, conditions that stimulate hepcidin formation may cause iron deficiency.
Iron balance is also affected by the amount of iron in our diet. Over time, diets low in iron may cause a deficiency. Likewise, an overdose of iron supplements may cause severe iron poisoning.
The rate of iron absorption from the digestive tract is tightly regulated by the hormone hepcidin. However, several iron overload disorders may disrupt this fragile balance.
Iron toxicity can be either sudden or gradual.
Many serious health problems may be caused by accidental overdoses, taking high-dose supplements for a long time, or chronic iron overload disorders.
Under normal circumstances, very little free iron circulates in the bloodstream.
It is safely bound to proteins, such as transferrin, which keep it from causing harm.
However, iron toxicity can significantly increase the levels of “free” iron in the body.
Free iron is a pro-oxidant – the opposite of an antioxidant – and may cause damage to cells.
Several conditions may cause this to happen. These include:
- Iron poisoning: Poisoning can occur when people, usually children, overdose on iron supplements
- Hereditary hemochromatosis: A genetic disorder characterized by excessive absorption of iron from food
- African iron overload: A type of dietary iron overload caused by high levels of iron in food or drinks. It was first observed in Africa, where homemade beer was brewed in iron pots.
Acute iron poisoning happens when people overdose on iron supplements. Single doses as low as 10–20 mg/kg may cause adverse symptoms. Doses higher than 40 mg/kg require medical attention.
Similarly, repeated high-dose iron supplementation may cause serious problems. Make sure to follow the instructions on iron supplements, and never take more than your doctor recommends.
Early symptoms of iron poisoning may include stomach pain, nausea and vomiting.
Gradually, the excess iron accumulates in internal organs, causing potentially fatal damage to the brain and liver.
The long-term ingestion of high-dose supplements may gradually cause symptoms similar to iron overload, which is discussed more below.
BOTTOM LINE:Iron toxicity refers to the harmful effects of excess iron. It may occur when 1) people overdose on iron supplements, 2) take high-dose supplements for too long or 3) suffer from a chronic iron overload disorder.
Hemochromatosis (Iron Overload)
What is hemochromatosis?
Hemochromatosis, also called iron overload, is a condition in which your body stores too much iron.
What is iron, and why do I need it?
Iron is a mineral found in certain foods. Your body needs iron to:
- Help hemoglobin in blood cells carry oxygen throughout your body.
- Make red blood cells.
- Produce certain hormones.
Normally, your intestines absorb just the right amount of iron from the food you eat. But with hemochromatosis, the body absorbs extra iron and stores it in your organs, especially your heart, liver and pancreas.
Why is too much iron dangerous?
Too much iron can be toxic.
In the heart, it can cause:
- Arrythmia (irregular heartbeat).
- Heart failure.
Too much iron in the liver can lead to:
- Cirrhosis (scarring).
- Enlarged liver.
- Liver cancer.
- Liver failure.
In addition, iron overload can cause:
- Arthritis (joint damage).
- Problems with the spleen, adrenal glands, pituitary gland, gallbladder or thyroid.
- Problems with the reproductive system, such as erectile dysfunction in men and early menopause in women.
- Skin that may look noticeably more gray or bronze than usual.
If the condition isn’t treated, it can lead to death.
How common is hemochromatosis?
The condition is fairly common, affecting more than a million Americans.
SYMPTOMS AND CAUSES
What causes hemochromatosis?
There are two types of hemochromatosis, each with different causes.
An inherited genetic change is the most common cause. It’s called primary hemochromatosis, hereditary hemochromatosis or classical hemochromatosis. With primary hemochromatosis, problems with the DNA come from both parents and cause the body to absorb too much iron.
In secondary hemochromatosis, medical treatments or other medical conditions cause the iron overload. Examples include:
- Anemia (low amount of red blood cells).
- Blood transfusions.
- Iron pills or injections.
- Kidney dialysis over a long period of time.
- Liver disease, such as hepatitis C infection or fatty liver disease.
Are certain people more likely to have primary hemochromatosis?
The inherited form of hemochromatosis is more common in white people with ancestors from Northern Europe. It’s less common in people with African-American, Hispanic, Asian or American Indian descent.
Men have hemochromatosis more than women. Women lose iron when they get their periods or have babies. Their bodies also store less iron. Hemochromatosis is also more common in older people because iron toxicity takes years to develop.
Other factors that increase the chances of developing hemochromatosis include alcohol abuse and a family history of:
- Heart attack.
- Erectile dysfunction.
- Liver disease.
What are the symptoms of hemochromatosis?
Not every person with hemochromatosis develops symptoms. Some people with high levels of iron don’t have any problems, while others experience very serious symptoms.
Symptoms usually don’t appear until middle age, and they often look like signs of other conditions. These signs may include:
- Fatigue (feeling tired a lot).
- General weakness.
- Heart flutters or irregular heartbeat.
- “Iron fist,” or pain in the knuckles of the pointer and middle fingers.
- Joint pain.
- Stomach pain.
- Unexplained weight loss.
Both iron overload and iron deficiency appear to make people more susceptible to infection There are two reasons for this:
- The immune system uses iron to kill harmful bacteria, so some amount of iron is needed to fight infections.
- Elevated levels of free iron stimulate the growth of bacteria and viruses, so too much iron can have the opposite effect and increase the risk of infections.
Several studies indicate that iron supplementation may increase the frequency and severity of infections, although a few studies found no effects
People with hereditary hemochromatosis are also more susceptible to infections.
For patients at a high risk of infection, iron supplementation should be a well-grounded decision. All potential risks should be taken into account.
BOTTOM LINE:Iron overload and high-dose iron supplementation may increase the risk of infection in certain individuals.
Most people don’t need to worry about getting too much iron from food alone. Even the best food sources contain only about 5 milligrams per serving, and most foods contain less than 3 milligrams per serving. Iron deficiency is much more likely than iron toxicity from foods. Keep iron supplements out of reach of children, and call poison control immediately if you suspect a child has taken an overdose of iron supplements, since this is more likely than consuming too much iron from food. People with hemochromatosis need to regularly have blood drawn to rid their bodies of the excess iron they can’t absorb.