Are you feeling too exhausted to get off the couch? Catching every cold that’s going around? Feeling lethargic? It could be iron deficiency. Women are more likely to be low in iron during their reproductive years, but don't rule out the troubles of a deficiency if you are older or of the opposite sex. Iron deficiency can affect men or women of any age.
Why Do We Need Iron?
Iron is required to produce hemoglobin in our red blood cells, which is why iron-fortified foods matter. Red blood cells, via hemoglobin, carry oxygen through your cells to every part of your body and organ systems. If your blood lacks enough healthy red blood cells or hemoglobin, a condition called anemia can result. Anemia affects over 3 million Americans. If your blood cells are not healthy, your body can't produce enough oxygen. And when your tissues, muscles and organs, including your heart, do not receive a sufficient amount of oxygen, it will cause your body to work twice as hard. The reduced oxygen also causes you to feel tired, weak, faint, dizzy and short of breath. You may even get headaches or heart palpitations.
Iron is also needed to make adenosine triphosphate (ATP), the fuel for each cell. If the body is low on fuel, it won’t run optimally. Iron is also needed for a variety of enzymes involved in proper brain, liver, and thyroid function; synthesis of hormones such as estrogen and progesterone; and heart health. Your body relies on a protein called ferritin to regulate your blood levels of iron. Ferritin will help store iron in the blood and release iron if concentrations are low.
Your body continually loses iron through normal processes such as urination, defecation, sweating, and sloughing off skin cells. Conditions linking iron deficiency and stomach pain, such as menstruation, pregnancy, cancer, surgery, bowel disorders (diverticulitis, polyps, IBC, Crohns, ulcerative colitis), stomach disorders and uterine fibroids may also affect your iron levels.
Symptoms of Iron Deficiency
Symptoms of iron deficiency include:
Dark circles under the eyes
Fatigue and muscle weakness
Increased infections
Shortness of breath
Heart palpitations
Poor concentration
Low, listless mood
Dizziness
Cold hands and feet
Chest pain during exercise
Restless legs
Increasing Your Iron Intake
Increasing iron levels can be done with food and/or through supplements. There are two types of iron found in food: heme iron and non-heme iron. Heme iron is the most absorbable form of iron and is found in an iron-rich diet including meats, poultry and fish. Good sources of non-heme iron, foods high with iron in plant form, are dried fruits, dark green leafy vegetables, legumes and whole grains. To boost absorption of non-heme iron in foods, combine these foods with vitamin C-rich foods, such as citrus fruit, berries, melons, peppers and tomatoes. Cooking with cast-iron cookware can also increase the amount of non-heme iron in foods.
If you are diagnosed with anaemia, dietary measures alone are often not enough to treat iron deficiency anaemia, therefore supplements play a vital role in managing this condition. There are many types of iron, from tablets to liquids, and one may be better for you than another. How well your body absorbs iron depends on the source of iron you consume and how healthy your gut is (you need a healthy gut to absorb iron).
The most common iron supplement recommended is "ferrous iron" because it is cheaper, provides a high dose of iron per tablet, and gets absorbed by the body quicker. However, it does have potential side effects such as nausea, bloating, heartburn, abdominal pain, constipation, and black/tarry stools. The low iron constipation people report after taking “ferrous iron” is related to the imbalance of gut microbes that is caused by this particular form of iron. An imbalance in your gut microbes can slow down peristalsis (the movement of feces through the colon), which results in feces staying in the colon longer. This results in more water being absorbed by the colon (causing dryer feces), further resulting in constipation.
If you have trouble with constipation, consider a plant-based iron. MegaFood Blood Builder is made from real food sources (beets, oranges) with added nutrients and has been clinically proven to increase iron levels without common gastrointestinal side effects, such as nausea or constipation. It also includes folic acid and B12 for healthy red blood cell production, and vitamin C to support iron absorption.
Another option is Gaia Herbs Plant Force Liquid Iron®. It is made with with nourishing foods and botanicals including beet root, dandelion, and Gaia-grown™ nettle. This liquid is gentle on the stomach and a good choice for those who do not want to swallow a tablet and have trouble with constipation.
For best results, take iron supplements between meals, and do not take them with milk, calcium, tea or coffee, as this may reduce absorption.
A man needs about 8 mg of iron daily, while women aged 19 to 50 need 18 mg, increasing to 27 mg during pregnancy. And even though the iron found in plant foods is less easily absorbed than the heme iron found in animal products, studies have shown that iron absorption from plant foods can be significantly increased when eaten along with vitamin C.
How to Check Your Iron Level
To find out if you are anemic or iron deficient, you can have a Anemia Blood Panel done.
Before taking a supplement, please consult with your primary care practitioner.
Iron Deficiency and Your Digestive System
A common question we get here at Village Green: Can iron deficiency cause constipation? The quick answer: not directly. But iron supplements, particularly ferrous iron, are often linked to constipation and other changes in bowel function. Here’s why.
Frequently Asked Questions
Can iron deficiency cause constipation?
Iron deficiency isn't a classic cause of constipation. The supplements used to correct it can be. Ferrous iron in particular is linked to constipation, bloating, and abdominal discomfort. What happens is a shift in your gut microbes. That shift slows the movement of waste through your colon. Constipated after starting iron? A gentler plant-based form may help support regularity.
A lack of iron itself typically isn't the cause of constipation. The supplement you take to correct low iron often is, however. Ferrous iron in particular is linked to constipation, coming down to how that form impacts your gut bacteria and slows digestion. If this affects you, ask about a gentler plant-based iron.
Anaemia on its own doesn't typically cause constipation. What tends to cause it is the iron therapy used to help with iron deficiency anaemia, especially ferrous salts, which are associated with slowed peristalsis and dryer, harder stools. A food-based or liquid iron is often better tolerated for those who struggle with this.
Does anemia cause constipation?
Anemia on its own doesn't typically cause constipation. What tends to cause it is the iron therapy used to help with iron deficiency anemia, especially ferrous salts. These forms are associated with slowed peristalsis and dryer, harder stools. A food-based or liquid iron is often better tolerated for those who struggle with this.
Can low ferritin cause constipation?
The protein which is responsible for storing iron is called ferritin. If your ferritin is low then this means that your iron stores are depleted. However, a low ferritin level does not cause constipation. It is usually only when you start taking iron in supplement form, especially ferrous iron, that the constipation starts. Taking iron between meals and choosing a gentler form may help support your gut while you rebuild your levels.
Can low iron make you constipated?
Low iron in itself typically isn’t the cause of constipation. The iron supplement you take to combat low iron often is, however. Ferrous iron is linked to constipation and other GI issues. This comes down to how that form impacts your gut bacteria and slows digestion. If you’re affected by this, ask for a plant-based iron formulation that’s easier on the digestive tract.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
References
- NIH Office of Dietary Supplements - Iron Fact Sheet for Health Professionals
- PubMed - Nutritional iron deficiency (2007)
- PubMed - Interaction of vitamin C and iron (1980)
- PubMed - Effect of tea and other dietary factors on iron absorption (2000)
- PubMed - Iron deficiency and anemia in pregnancy: a call to action! (2025)
- PubMed - Nutritional Strategies for Managing Iron Deficiency in Adolescents (2024)
- PubMed - Iron requirements of infants and toddlers (2014)
- PubMed - Systematic review: influence of iron deficiency anemia on HbA1c (2021)
- MedlinePlus - Anemia
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