Does Iron Cause Constipation?
Oral iron supplements may cause or worsen constipation
Medically reviewed by Kashif J. Piracha, MD
Some iron supplements can cause constipation. Iron is a mineral that your body uses to make hemoglobin, a protein found in red blood cells that carries oxygen from the lungs to every cell in your body. Because the human body does not produce iron, we must get this mineral from food.
Some people have a hard time keeping their iron at healthy levels. You may need an iron supplement if you can't increase iron levels through your diet.
This article will explore the link between iron and constipation.
Carol Yepes / Getty Images
Understanding the Link Between Iron and Constipation
Constipation is a frequent side effect of taking iron supplements, but the exact mechanism that links iron and constipation is unclear. Researchers believe that extra iron in the stomach may cause water to move into the intestines. This activity takes water away from the lower intestine, causing stools to become harder.
Tips for Managing Constipation While Taking Iron Supplements
If you're diagnosed with iron deficiency, increasing iron-rich foods may not be enough to get your iron to healthy levels. If you have to take iron supplements, some ways to prevent or alleviate constipation include:
Bowel training (training yourself to have a bowel movement at the same time daily).
Drinking plenty of liquids, like water, soups, and broths.
Eating fiber-rich foods like vegetables, nuts, beans, whole grains, and fruits.
Getting regular physical activity, such as brisk walking, swimming, or biking.
Additional Methods to Ease Constipation
Discuss other treatment options with a healthcare provider if diet, adequate liquids, and physical activity don’t help ease constipation. There are over-the-counter medications that help with constipation, including:
Lubricants (e.g., Fleet)
Osmotic agents (e.g., Milk of Magnesia or Miralax)
Stimulants (e.g., Correctol, Dulcolax)
Stool softeners
Iron is best absorbed on an empty stomach, which may cause gastrointestinal symptoms like constipation. Try taking your iron with a little bit of food. Consider alternative ways to take iron, such as intravenous (IV) iron, or talk to a healthcare provider about switching to an iron supplement that is gentler on your stomach.
Combating Iron Constipation for Different Use Cases
There are many reasons a healthcare provider may recommend iron supplementation. It's important to take iron as instructed by a healthcare provider since untreated iron deficiency can lead to other health problems.
If you experience constipation from iron supplementation, talk to a healthcare provider for strategies to combat constipation. They may recommend the following:
Increase your water intake.
Take the supplement with food.
Take a lower dose of the supplement.
Try a different type of iron supplement.
The following conditions and eating patterns commonly benefit from iron supplementation.
Iron-Deficiency Anemia
Iron-deficiency anemia is the most common type of anemia with various causes—heavy menstrual bleeding being the primary cause in people who menstruate. If you have this type of anemia, a provider may recommend incorporating iron-rich foods into your diet or including an iron supplement.
Pregnancy
Pregnant people often require additional iron since some of their blood supply is shared with the fetus. If you have iron deficiency during pregnancy, a healthcare provider may recommend diet changes, exercise, or a different iron supplement. In some cases, certain laxatives are beneficial, but it's crucial to consult a provider before taking them, as they can have adverse effects on your pregnancy.
Vegetarian or Vegan Diets
Nonheme iron—the type found in plants—is harder for the body to absorb and is available in smaller quantities per serving. If you follow a vegetarian or vegan diet pattern, you may require iron supplementation.
Related: 17 Iron-Rich Vegetarian Meals
Which Form of Iron is Least Constipating?
Iron supplements are made from different forms of iron. Each form offers a different amount of elemental iron, the amount of iron your body absorbs. Supplements with higher elemental iron are more likely to cause stomach issues like constipation. Below are some common forms of iron and the amount of elemental iron a dose of each contains:
Ferrous bisglycinate: 25 milligrams (mg)
Ferrous sulfate: 65 mg
Ferric citrate: 210 mg
Ferrous sulfate is the most commonly used form of iron in supplements.
When Not to Take Iron Supplements
Certain medications and supplements should not be taken with iron. Here are some common examples:
Levodopa (brand name Rytary): This medication is prescribed to people with Parkinson’s disease and restless legs syndrome. Taking iron with it can make it less effective.
Levothyroxine (brand name Synthroid): This medication is used to treat hypothyroidism, goiter, and thyroid cancer; iron can make it less effective.
Proton pump inhibitors (PPI): These include antacids like Prilosec and Prevacid. They lower the amount of acid in the stomach, which can reduce the amount of iron you absorb from supplements.
Calcium: Eating foods high in calcium or calcium supplements with iron supplements can prevent your body from absorbing iron.
If you need to take iron supplements, tell your healthcare provider about all medications and supplements you take. They will create the best treatment plan for you.
In addition, if you do not have iron deficiency, do not take iron supplements. Too much iron can cause health problems, such as stomach ulcers and decreased zinc absorption. Very high doses can lead to severe consequences, such as organ failure, coma, or death.
When to Contact a Healthcare Provider
Sometimes, constipation can be a sign of a serious health condition, like colorectal cancer. Make an appointment to see a healthcare provider if your symptoms haven’t improved within a week or you notice these symptoms:
Bleeding from your rectum or blood in your stool
Inability to pass gas
Losing weight without trying
Lower back pain
Severe stomach pains
Vomiting or fever
Summary
If you need to take iron supplements, eat fiber-rich foods, drink plenty of water, and stay physically active. Too much iron can lead to constipation. You may consider training yourself to have daily bowel movements. You can take stool softeners or fiber supplements if diet changes don't ease constipation.
Call your healthcare provider if your symptoms last longer than a week or if you have blood in your stool.
Read the original article on Verywell Health.
