If you have ulcerative colitis (UC) and are experiencing fatigue, it could be a symptom of anemia. Anemia develops in up to one-third of people with inflammatory bowel diseases (IBD), often caused by bleeding ulcers in the colon, ongoing inflammation, and reduced nutrient absorption.
Here’s what to know about the connection between ulcerative colitis and anemia, the signs and symptoms of anemia, and how to treat it with medication and lifestyle strategies.
Ulcerative Colitis and Anemia: What's the Link?
Ulcerative colitis is a chronic condition that occurs when your immune system targets the tissue of your large intestine’s inner lining, causing inflammation. It’s a type of inflammatory bowel disease (IBD). Ulcerative colitis can cause blood loss, often leading to iron deficiency anemia.
Anemia develops when there aren’t enough healthy red blood cells to carry oxygen around the body. Iron deficiency is the most common cause of anemia and most often occurs because of blood loss resulting from injury or chronic disease. It is estimated that 20 to 54 percent of people with IBD have low iron levels.
But iron deficiency isn’t the only cause of anemia; it can also develop due to a vitamin B12 deficiency, inflammation, or genetics. According to a review published in 2021, vitamin B12 and folate deficiencies due to issues with nutrient absorption may also cause anemia in those with IBD.
In ulcerative colitis, ulcers can develop along the lining of the intestines. This, along with inflammation, can lead to chronic bleeding, which can result in anemia. IBD can also lead to flares of ongoing inflammation that prevent the body from making a healthy amount of red blood cells, a condition known as anemia of chronic disease (ACD).
People with IBD can have both iron deficiency anemia and ACD.
Low red blood cell levels might develop because of increased levels of a hormone called hepcidin, which increases in response to inflammation-linked proteins called cytokines. This hormone controls how much iron you absorb into the bloodstream, and high levels make iron absorption harder. High hepcidin is often a sign of anemias not related to iron deficiency, like anemia of chronic disease. Iron deficiency anemia may lead to low hepcidin levels as the body attempts absorb more iron.
5 Complications of Ulcerative Colitis
Ulcerative colitis is an autoimmune disease and a form of IBD. Complications from UC affect more than just the digestive track. Here are some things to watch out for.
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What Are the Signs and Symptoms of Ulcerative Colitis and Anemia?
UC can cause uncomfortable, sometimes debilitating symptoms. Most often, these symptoms include painful belly cramps and diarrhea. The stool may contain pus, mucus, or blood, and the blood loss can contribute to anemia. Other symptoms might include:
Nausea
Loss of appetite
Urgent need to have a bowel movement
Extreme tiredness
Fever
Rarely, ulcerative colitis can also impact the eyes, joints, skin, kidneys, and liver. Both UC and anemia can lead to fatigue, which is the hallmark symptom of anemia. Other anemia symptoms may include:
A rapid heartbeat
Breathlessness
Chest pain
Dizziness
Headaches
Paleness
A mild case of anemia may not cause any symptoms, at least at first.
“I was frequently passing blood with my bowel movements and I found myself getting increasingly tired,” Dr. Bhargava says. “I wasn’t surprised at all to find that I had iron deficiency anemia.”
UC can complicate diagnosing iron deficiency anemia. If UC is behind your anemia symptoms, it may be masking the condition, especially if you feel extremely tired.
Blood tests used to diagnose anemia include:
Complete Blood Count This test checks blood cell levels, with a close focus on red blood cells. A doctor may also check your iron levels, iron stores, and vitamin B12 levels.
Hemoglobin Test This checks the part of a red blood cell that carries oxygen. Doctors often use this to diagnose anemia.
Hematocrit Test This measures the amount of red blood cells in your blood.
Peripheral Blood Smear This checks the size and shape of blood cells under a microscope.
How Is Ulcerative Colitis-Related Anemia Treated?
The best treatment for anemia with UC depends on the cause. In general, managing UC-related anemia involves both medical management and lifestyle adjustments.
Medical Treatments
The best way to treat UC-related anemia is to manage ulcerative colitis. This can help control the bleeding in the large intestine to limit blood loss (and the resulting iron deficiency anemia) and reduce inflammation to treat ACD.
Medicines to treat UC include:
Aminosalicylates
Corticosteroids
Immunosuppressants
Biologics
Small-molecule medicines
People with severe bleeding or disease that doesn’t respond to medications may need surgery that removes part of the rectum and colon and alters the way the body processes stool, like an ileostomy or ileoanal reservoir surgery.
If the cause of anemia is iron deficiency, treatment will involve iron supplementation in the form of an oral supplement. Those who have an active UC flare or don’t tolerate oral supplements well may receive iron intravenously; iron delivered via an IV is more easily absorbed and can raise your iron stores quicker. A healthcare provider may also prescribe vitamin B12 and folic acid supplements if necessary.
Blood transfusions, or the replacement of a specific volume of blood with healthy donated red blood cells, may be necessary for people with severe ACD or in those with severe rectal bleeding.
Bhargava says the key to treating his iron deficiency was getting his ulcerative colitis under control so his body could absorb iron properly.
Although the hospital treatment helped his ulcerative colitis symptoms, Bhargava continued to be deficient in iron. “It was challenging just to get up in the morning and go to work,” he says. “And because the tiredness was getting worse, the frequency of bowel movements would get worse, and I’d lose more blood with every bowel movement.”
After speaking with an hematologist at the hospital in New York City where he worked, Bhargava tried intravenous iron infusions and vitamin B12 injections, treatments commonly used to counteract chemotherapy side effects.
“It almost instantaneously helped my energy levels,” he says. “And it also helped my colitis symptoms.”
If your symptoms improve and your UC stays in remission, you’ll likely be tested for anemia every 6 to 12 months. Those with active disease and symptoms should undergo screening every three months. People living with UC should also receive annual screening for vitamin B12 and folic acid, as low levels of these can also cause anemia.
Lifestyle Factors
In addition to medical treatments, dietary modifications can help manage UC flare-ups. These include:
Identifying and avoiding trigger foods, like dairy or high-fiber foods
Drinking fluids often
Limiting or avoiding drinks containing alcohol and caffeine
Physical exercise and managing stress can also prevent flares and preventing flares may help decrease likelihood of developing iron deficiency.
Bhargava became a vegetarian and started practicing pranayama, a form of yoga breathing. He also takes ayurvedic herbal supplements and remains free of both UC and iron deficiency symptoms.
After your body’s iron stores are back up, eating iron-rich foods such as the following can help maintain them:
Iron-fortified cereals
Oysters
Beans
Beef
Beef liver
Spinach
Tofu
Sardines
Canned or stewed tomatoes
The Takeaway
Anemia is a common complication of ulcerative colitis, caused by bleeding in the colon, inflammation, or issues with nutrient absorption.
Both conditions cause fatigue, but anemia may not have symptoms at all, making it hard to detect in people with ulcerative colitis. Regular anemia screening is crucial, so ask your doctor about options.
Anemia treatments involve controlling ulcerative colitis inflammation through trigger avoidance, medications, or surgery, and replenishing iron, vitamin B12, or folate levels, depending on the deficiency.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resál T et al. Iron Deficiency Anemia in Inflammatory Bowel Disease: What Do We Know? Frontiers in Medicine. July 1, 2021.
Lopes AI et al. Portuguese Consensus on Diagnosis, Treatment, and Management of Anemia in Pediatric Inflammatory Bowel Disease. Portuguese Journal of Gastroenterology. January 10, 2020.
Yuying Luo, MD, is an assistant professor of medicine at Mount Sinai West and Morningside in New York City. She aims to deliver evidence-based, patient-centered, and holistic care for her patients.
Her clinical and research focus includes patients with disorders of gut-brain interaction such as irritable bowel syndrome and functional dyspepsia; patients with lower gastrointestinal motility (constipation) disorders and defecatory and anorectal disorders (such as dyssynergic defecation); and women’s gastrointestinal health.
She graduated from Harvard with a bachelor's degree in molecular and cellular biology and received her MD from the NYU Grossman School of Medicine. She completed her residency in internal medicine at the Icahn School of Medicine at Mount Sinai, where she was also chief resident. She completed her gastroenterology fellowship at Mount Sinai Hospital and was also chief fellow.
Adam is a freelance writer and editor based in Sussex, England. He loves creating content that helps people and animals feel better. His credits include Medical News Today, Greatist, ZOE, MyLifeforce, and Rover, and he also spent a stint as senior updates editor for Screen Rant.
As a hearing aid user and hearing loss advocate, Adam greatly values content that illuminates invisible disabilities. (He's also a music producer and loves the opportunity to explore the junction at which hearing loss and music collide head-on.)
In his spare time, Adam enjoys running along Worthing seafront, hanging out with his rescue dog, Maggie, and performing loop artistry for disgruntled-looking rooms of 10 people or less.
