Can IBD cause low folate? Understanding nutrient deficiencies in inflammatory bowel disease

October 13, 2025 •

4 min read

According to a 2017 meta-analysis, the average serum folate concentration in patients with inflammatory bowel disease (IBD) is significantly lower than in healthy controls. The chronic intestinal inflammation, dietary restrictions, and certain medications associated with the condition can cause or worsen this deficiency.

Quick Summary

Inflammatory bowel disease can lead to low folate levels through a combination of impaired nutrient absorption, dietary limitations, and drug interactions. This deficiency can cause symptoms like fatigue, anemia, and mouth ulcers. Managing folate status involves regular monitoring, dietary adjustments, and strategic supplementation under medical supervision.

Key Points

Inflammation impairs absorption: Chronic inflammation in the small intestine, especially with Crohn's disease, can directly damage the intestinal lining and prevent proper folate absorption.
Medications block folate: Some IBD treatments, like sulfasalazine and methotrexate, are known to interfere with folate metabolism and absorption, necessitating supplementation.
Dietary habits contribute to low levels: Many IBD patients restrict their diets during flare-ups, leading to lower intake of folate-rich foods like vegetables and legumes.
Symptoms mimic IBD flares: Folate deficiency can cause fatigue, weakness, and mouth ulcers, symptoms that can easily be mistaken for an IBD flare-up.
Supplementation is often necessary: Due to malabsorption and other factors, oral folic acid supplementation is often required, and dosage may need adjustment, particularly for those on specific medications.
Regular monitoring is critical: Healthcare providers should regularly test folate levels in IBD patients, especially those with small bowel involvement or on relevant medications, to catch and treat deficiencies early.
Dietary caution is key: While supplementation helps, IBD patients can introduce easily digestible, folate-rich foods during remission with a dietitian's guidance.

The Connection Between IBD and Low Folate

Inflammatory bowel disease (IBD) is a group of chronic inflammatory conditions affecting the gastrointestinal (GI) tract, including Crohn's disease (CD) and ulcerative colitis (UC). The chronic nature of the disease, often characterized by periods of flare-ups and remission, makes individuals susceptible to a range of nutritional deficiencies, with folate being a prime example.

Folate, or vitamin B9, is a water-soluble vitamin essential for the synthesis of DNA, the formation of red blood cells, and overall cellular health. Given that it is primarily absorbed in the small intestine, it is especially vulnerable to disruption when inflammation is present.

How IBD disrupts folate levels

There are several interconnected reasons why IBD patients are at a high risk for developing low folate levels:

Malabsorption: The inflammation associated with IBD can damage the intestinal lining, particularly in the duodenum and jejunum where folate is primarily absorbed. In Crohn's disease, inflammation in the small intestine can directly impair this absorption process.
Dietary Restrictions: Many IBD patients adopt restrictive diets to manage their symptoms, often avoiding certain foods that are rich in folate, such as leafy green vegetables and beans, which they may find difficult to tolerate during flare-ups.
Medication Interference: Some common IBD medications are known to disrupt folate metabolism. Sulfasalazine, for instance, is a medication known to impair the absorption of folic acid. Similarly, methotrexate, another drug used to treat IBD, is a folate antagonist that interferes with its utilization.
Increased Utilization: The constant inflammatory process and high cellular turnover in IBD can increase the body's demand for folate, which is needed for rapid cell division and tissue repair. The body's reserves can become depleted more quickly than in a healthy individual.

Symptoms and consequences of folate deficiency

The symptoms of low folate in IBD can be subtle and may overlap with general IBD symptoms, making them easy to miss. Common signs include:

Fatigue and Weakness: One of the most prevalent symptoms, caused by the resulting macrocytic anemia, where red blood cells are abnormally large and fewer in number.
Mouth Sores and Glossitis: Inflammation of the tongue (glossitis) and mouth ulcers are tell-tale signs of a deficiency.
Neurological Symptoms: While more common with B12 deficiency, low folate can cause symptoms like poor concentration, low mood, and irritability.
Increased Homocysteine Levels: Folate is crucial for breaking down the amino acid homocysteine. When folate levels are low, homocysteine can build up, potentially increasing the risk of cardiovascular complications.

Managing folate levels in IBD

Proper management of folate is crucial for IBD patients to avoid deficiency and its complications. This is a personalized process that should be guided by a healthcare provider, often involving a registered dietitian.

Comparison of Folate Sources for IBD Patients


Source Type	Examples	Bioavailability	Considerations for IBD
Dietary Folate	Leafy green vegetables (spinach, kale), legumes (lentils, chickpeas), asparagus, fortified grains	Variable and often lower than folic acid	May be poorly tolerated during flares due to high fiber content. Must be eaten consistently.
Folic Acid Supplements	Oral folic acid tablets	High (85–100%)	Generally well-absorbed. Dosage may need to be adjusted based on medication use, such as with sulfasalazine or methotrexate.
Fortified Foods	Fortified cereals, bread, pasta	Good, often higher than natural folate	Useful for consistent intake, but absorption may still be impacted by intestinal damage.
Methylated Folate Supplements	L-methylfolate supplements	Very high	Recommended for those with an MTHFR gene mutation who cannot properly metabolize folic acid.

The role of supplementation

For many IBD patients, dietary sources alone are not sufficient to maintain adequate folate levels. Supplementation with folic acid is often necessary, especially for those on specific medications or with extensive small bowel disease. Your doctor will determine the appropriate dose based on your individual needs and medication regimen. In cases of active inflammation or following bowel resection, supplementation is a crucial part of treatment.

Screening and monitoring

Regular blood tests are essential for monitoring folate levels in IBD patients. The European Crohn's and Colitis Organization (ECCO) recommends that folate concentration be tested frequently, especially in patients with small intestine involvement or after intestinal resection. These tests can help diagnose and track the deficiency, allowing for timely and effective treatment.

Proactive dietary strategies

When not in a severe flare-up, incorporating well-tolerated folate-rich foods is a key part of managing IBD. This can be done gradually under the guidance of a dietitian to minimize symptom aggravation.

Cooked, Tender Vegetables: Steaming or boiling leafy greens can make them easier to digest and absorb. Starting with small portions and gradually increasing can help determine tolerance.
Mashed Legumes: Well-cooked and mashed beans or lentils can be a gentle way to introduce these folate powerhouses into the diet.
Fortified Grains: Opting for fortified cereals, bread, or rice can provide a reliable and digestible source of folic acid.

The bigger picture: A comprehensive approach

While addressing low folate is important, it is part of a broader nutritional strategy for IBD patients. Other common deficiencies, such as vitamin B12, vitamin D, iron, and zinc, also need to be monitored and managed. A holistic approach that includes diet, supplementation, and regular medical check-ups is the most effective way to ensure optimal nutrient status and overall health.

Conclusion

Yes, IBD can absolutely cause low folate levels. This is a common and often overlooked complication of the disease, resulting from a combination of poor absorption due to inflammation, self-imposed dietary restrictions, and interactions with certain medications. Addressing this deficiency is vital for preventing anemia, fatigue, and other adverse health effects. By working closely with healthcare professionals to monitor folate status, tailor dietary intake, and provide appropriate supplementation, patients can effectively manage their condition and improve their quality of life. The proactive management of nutritional deficiencies is a cornerstone of comprehensive IBD care.

Frequently Asked Questions

The primary reasons are impaired absorption due to chronic intestinal inflammation, poor dietary intake from restricted eating, and the inhibitory effects of certain IBD medications like sulfasalazine and methotrexate.

Common signs include fatigue, weakness, shortness of breath, a sore tongue or mouth ulcers, and difficulty concentrating. These can be mistaken for IBD symptoms, so testing is crucial.

For many IBD patients, diet alone is insufficient due to malabsorption issues and food intolerances, especially during flare-ups. Supplementation with folic acid is often necessary in addition to dietary adjustments.

Sulfasalazine is a well-known medication that can interfere with folate absorption. Methotrexate, another IBD drug, also interferes with folate utilization.

Low folate is diagnosed with blood tests that measure serum or red blood cell folate levels. These tests should be performed regularly as recommended by your gastroenterologist.

Crohn's disease, particularly when it affects the small intestine (where folate is absorbed), is strongly associated with folate deficiency. However, it can also occur in ulcerative colitis.

Folate is the naturally occurring form of vitamin B9 found in foods, while folic acid is the synthetic form used in supplements and fortified foods. Folic acid generally has higher bioavailability.