Side Effects of Iron Tablets

There can be some life threatening side effects with iron tablets.
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Iron tablets are available over the counter as individual supplements or in multivitamins. It's important that you monitor your dosage, as iron can cause long-term harm to your body if you ingest too much. Side effects can be severe, especially for children if they accidentally swallow iron pills.


Iron Benefits and Requirements

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Iron is a mineral that is essential to your health for efficient production of red blood cells. Almost two-thirds of the iron in your body is found in your hemoglobin. You need iron to help transport oxygen from your lungs to all tissues of your body, which affects everything from brain function to controlling your muscles. Iron is also needed to maintain a healthy immune system.

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The daily iron requirements your body needs for optimal health have been determined by the Institutes of Medicine according to age and gender. These amounts represent the total recommended intake from food, multivitamins and supplements.

  • Children 1 to 3 years: 7 milligrams; 4 to 8 years: 10 milligrams; 9 to 13 years: 8 milligrams
  • Teens 14 to 18 years: boys — 11 milligrams; girls — 15 milligrams
  • Adults 19 to 50 years: women — 18 milligrams; men — 8 milligrams
  • Adults 51 years and older: 8 milligrams
  • Pregnant and lactating women: 9 to 27 milligrams


Food Sources of Iron

You can get iron from many foods but the type found in animal foods, called heme iron, is more easily absorbed than iron from plant-based sources, or non-heme iron. Many foods are fortified with non-heme iron, such as breads and breakfast cereals. Some foods that are good sources of iron include:

  • Meat, including organ meat, beef, turkey, lamb
  • Fish and seafood including, tuna, oysters, clams, shrimp
  • Beans and legumes, including kidney beans, lima beans, lentils
  • Vegetables, including spinach and peas
  • Nuts and some dried fruits, such as raisins


To enhance the absorption of iron from foods, include vitamin C-rich foods or beverages with your meals.

Read more: Foods That Inhibit Iron Absorption

Do You Need Iron Tablets?

Although food is always the best way to get your nutrients, you may find that your diet cannot sufficiently supply your need for iron. Certain situations may put you at risk for iron deficiency, which might require your use of iron pills. Some of these include:


  • Being pregnant
  • Eating a vegetarian or vegan diet
  • Frequently donating blood
  • Having a medical condition or intestinal disorder that inhibits the absorption of nutrients, such as celiac disease
  • Experiencing heavy periods
  • Blood loss from conditions such as peptic ulcer, a colon polyp or hiatal hernia


If you have any of these conditions, you risk having a low iron level. A deficiency in iron may not be noticeable in the short term because your body can use stored iron. When your stores are depleted, it can result in iron deficiency anemia. Some symptoms of iron deficiency anemia are:


  • Extreme fatigue and weakness
  • Pale skin
  • Chest pain, fast heartbeat or shortness of breath
  • Headache or dizziness
  • Cold hands and feet
  • Inflammation or soreness of the tongue
  • Brittle nails
  • Cravings for unusual substances, such as ice, dirt or starch
  • Poor appetite, especially in infants and children

How to Take Iron Supplements

If you think you are deficient in iron, see your doctor for a diagnosis. You should not try to treat a deficiency with iron supplements on your own because an improper dosage can be dangerous. Excess iron can accumulate in your organs and may result in damage to your liver and cause other complications.


Because of the danger of overdosing with iron supplements, upper limits have been established as a guideline. Read the labels of your iron products to ensure you are within these safety ranges:

  • Children: 1 to 13 years — 40 milligrams
  • Teens: 14 to18 years — 45 milligrams
  • Adults: 19 years and older — 45 milligrams

Iron supplements are available by prescription or in over-the-counter multivitamins or stand-alone forms. These include tablets and liquids, some in a slow-release form. The various formulations can differ significantly in their iron content. The highest amount of iron content is typically found in prenatal vitamins.


Iron supplements can use different types of salts. The main types are:

  • Ferrous sulphate — high strength, typically contain 65 milligrams or 20 percent elemental iron per tablet.
  • Ferrous fumarate — tablets or syrup, typically contain 33 milligrams or 33 percent elemental iron per dose.
  • Ferrous gluconate — typically contains 36 milligrams or 12 percent elemental iron per tablet.


Children's vitamins may provide from 5 to 19 milligrams of elemental iron per tablet. Prenatal vitamins usually contain the most iron — 60 to 90 milligrams, making them potentially dangerous for young children who accidentally ingest them.

Iron tablets should be taken on an empty stomach and preferably an hour before a meal. Take your supplement with a glass of orange juice or other vitamin C-rich drink. Avoid eating food or drinking tea and milk one hour before taking your supplement so you don't reduce the absorption of iron. Also be aware of any medications you are taking, including antacids and antibiotics, which could inhibit absorption of the iron from your gut.

Read more: Are Supplements Safe? Here's What You Really Need to Know

Iron Supplement Side Effects

The severity of side effects from an overdose depends on the form of iron salts in the iron pill. Ingesting 20 to 60 milligrams per kilogram of elemental iron can cause some mild side effects; intake of more than 60 milligrams per kilogram can be life-threatening, according to the report from a study published in StatPearls in June 2019.

The side effects from taking too much iron can range from gastrointestinal discomfort to serious poisoning that is a medical emergency, depending on the individual and amount of iron ingested. The progression of symptoms most often occur in five stages:

Stage 1 symptoms: During the first six hours after ingestion, initial side effects may include:

  • Vomiting, often with blood
  • Diarrhea or bloody stools
  • Abdominal pain

Stage 2 symptoms: This is the latent period. Within six to 24 hours after an overdose, you may appear to recover and many symptoms can vanish.


Stage 3 symptoms: In six to 72 hours after ingestion, there may be a recurrence of gastrointestinal symptoms in addition to:

  • Shock
  • Metabolic acidosis
  • Excessive bleeding
  • Liver damage
  • Very low blood pressure
  • Renal failure

Stage 4 symptoms: In 12 to 96 hours after overdose, symptoms may be very severe and can include:

  • Liver failure

Stage 5 symptoms: Two to eight weeks after overdose, lasting symptoms from the consequences of healing the injured mucus membranes of your intestinal tract could include:

  • Gastric scarring
  • Obstruction or narrowing of the stomach or small intestines

Treatments and Prognosis

If you incur an iron overdose, the more quickly you receive treatment, the better the chance for survival. If the side effects disappear within 48 hours, the chances of recovery are good. However, severe liver damage is a concern if symptoms last two to five days after an overdose. Some people have died even up to a week later.

Getting emergency attention is vital if you or someone you know has accidentally or intentionally ingested an excessive amount of iron. Some treatments for iron poisoning include:

  • Intravenous fluids

  • Medication that

    helps remove iron from the body and treat symptoms

  • Endoscopy, which involves viewing the esophagus and stomach with a camera and tube

  • Whole bowel irrigation to flush the iron through the stomach and intestines

  • Breathing support, including by means of a ventilator




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