Written by Dr. Antonia Repollet
Licensed Clinical Psychologist
Certified School Psychologist
GI Psychology
We often think of Crohn’s disease and ulcerative colitis as conditions driven by inflammation, immune dysregulation, and medication management. But another side of IBD is rarely talked about, one that can quietly worsen symptoms, mimic anxiety or depression, and contribute to flare-like fatigue even when inflammation is controlled: nutrient deficiencies.
Many people with IBD assume that if their bloodwork is “normal”, they’re nutritionally fine. Yet research shows that vitamin and mineral deficits are extremely common in IBD, even when a person is in clinical remission, eating well, and/or absorbing enough calories (Weisshof & Chermesh, 2015).
These deficiencies don’t just affect physical health; they affect mood, cognition, energy, and the gut–brain axis itself.
Let’s break down what you need to know!
“Normal” Bloodwork Doesn’t Always Mean Nutrient Sufficiency
Standard labs often measure red blood cell size or hemoglobin to evaluate anemia. But a person can have normal hemoglobin and still be deficient in iron, B12, and/or folate — especially if they’re absorbing less due to inflammation, altered gut anatomy, or diarrhea (Niepel et al., 2018).
This is why a proper IBD lab panel should include tests like ferritin, iron saturation, magnesium, B6 and B12, vitamin D, calcium, folate, and zinc— not just CBC (Issokson, 2017).
Common Deficiencies in IBD (& The Symptoms They Mimic)
Iron
- Common in both Crohn’s & UC.
- Can be low even without anemia.
- Hard to absorb during inflammation.
Symptoms that overlap with anxiety or fatigue:
- Racing heart
- Breathlessness
- Dizziness
- Cold intolerance
- Hair loss
- Chronic tiredness that isn’t relieved by sleep
Tip: If hemoglobin is normal, ferritin may still be low — ferritin under 100 suggests iron deficiency and under 30 is an even clearer sign of deficiency (Abitbol et al., 2015).
Vitamin B12
Often low in Crohn’s affecting the ileum or after surgery. Also depleted by metformin and some heartburn medications (Pan et al., 2017).
Symptoms:
- Brain fog
- Numbness/tingling in hands/feet
- Low mood
- Memory issues
- Fatigue
Vitamin D
Malabsorption, inflammation, and limited sunlight all contribute.
Symptoms:
- Fatigue
- Low mood or irritability
- Weakened immunity
- Bone pain
Vitamin D also plays a role in immune regulation, meaning deficiency may contribute to flares (Fletcher et al., 2019).
Zinc
Diarrhea rapidly depletes zinc. Low zinc can impair digestion and immune function (Siva et al., 2017).
Symptoms:
- Worsened diarrhea
- Delayed healing
- Altered taste/smell
- Poor appetite
- Skin changes
Other Nutrients “At-Risk”
- Folate
- Magnesium
- Copper
- Selenium
- Calcium
Each affects cellular repair, absorption, and gut motility (Balestrieri et al. 2020).
When Fatigue Isn’t (Just) Depression
Fatigue in IBD is often dismissed as stress, anxiety, or “being run down”. While the emotional impact of IBD absolutely matters, nutrient deficiency is a biologically driven cause of exhaustion that behavioral tools alone cannot fix.
Here’s where psychology and medicine intersect: Fatigue that doesn’t improve with rest should be evaluated for nutrient deficits — not automatically labeled as depression, IBS, or burnout.
Patients deserve clinicians who treat both the emotional and biological contributors to symptoms.
Advocating for Proper Testing
Ask your Gastroenterologist or Primary care Provider (PCP) about ordering:
- CBC + Ferritin + Iron Panel
- Vitamin B12
- Folate
- Vitamin D
- Zinc
If you have chronic diarrhea, low weight, Crohn’s ileitis, or fatigue out of proportion to your inflammation markers, testing may need to be repeated every 3-6 months (Maaser et al., 2019).
What About Supplementing?
Supplements are not one-size-fits-all. Too much iron, B12, zinc, or vitamin D can also cause problems.
Whenever possible, evaluation and supplementation should be:
- Guided by labs
- Coordinated with an nutritionist or registered dietician (RD) who specializes in IBD
The Gut–Brain Connection: Why Deficiencies Matter in Behavioral Health
Low nutrients can:
- Worsen cognitive fog
- Impact mood regulation
- Increase physical sensitivity to pain
- Reduce the body’s ability to feel energized
- Heighten anxiety responses due to physiological stress
When we treat IBD from a gut–brain perspective, nutrient status becomes part of mental health care, not just medical care.
Bottom Line
If you’re feeling exhausted, foggy, moody, or “not yourself”, it may not just be stress or gut symptoms. Nutrient deficits are a hidden, fixable contributor to daily life with IBD.
You deserve care that considers the whole picture.
If you’re a patient, advocate for proper testing. If you’re a clinician, include nutrition and lab evaluation as part of comprehensive treatment. If you live with IBD, remember: your body is working harder than most — and it needs support, not blame.
Adults who are ready to explore evidence-based tools to manage stress and IBD symptoms can enroll in our IBD Psychotherapy Group to explore how therapy, clinical hypnosis, and mind-body strategies can support their journey toward healing.
References
Abitbol, V., Borderie, D., Polin, V., Maksimovic, F., Sarfati, G., Esch, A., Tabouret, T., Dhooge, M., Dreanic, J., Perkins, G., Coriat, R., & Chaussade, S. (2015). Diagnosis of Iron Deficiency in Inflammatory Bowel Disease by Transferrin Receptor-Ferritin Index. Medicine, 94(26), e1011. https://doi.org/10.1097/MD.0000000000001011
Balestrieri, P., Ribolsi, M., Guarino, M. P. L., Emerenziani, S., Altomare, A., & Cicala, M. (2020). Nutritional Aspects in Inflammatory Bowel Diseases. Nutrients, 12(2), 372. https://doi.org/10.3390/nu12020372
Fletcher, J., Cooper, S. C., Ghosh, S., & Hewison, M. (2019). The Role of Vitamin D in Inflammatory Bowel Disease: Mechanism to Management. Nutrients, 11(5), 1019. https://doi.org/10.3390/nu11051019
Issokson, K. (2017). Common Micronutrient Deficiencies in IBD. The Crohn’s & Colitis Foundation. https://www.crohnscolitisfoundation.org/sites/default/files/legacy/science-and-professionals/nutrition-resource-/micronutrient-deficiency-fact.pdf
Maaser, C., Sturm, A., Vavricka, S. R., Kucharzik, T., Fiorino, G., Annese, V., Calabrese, E., Baumgart, D. C., Bettenworth, D., Borralho Nunes, P., Burisch, J., Castiglione, F., Eliakim, R., Ellul, P., González-Lama, Y., Gordon, H., Halligan, S., Katsanos, K., Kopylov, U., … Stoker, J. (2018). Ecco-ESGAR guideline for Diagnostic Assessment in IBD part 1: Initial diagnosis, monitoring of known IBD, detection of complications. Journal of Crohn’s and Colitis, 13(2), 144-164K. https://doi.org/10.1093/ecco-jcc/jjy113
Niepel, D., Klag, T., Malek, N. P., & Wehkamp, J. (2018). Practical guidance for the management of iron deficiency in patients with inflammatory bowel disease. Therapeutic Advances in Gastroenterology, 11. https://doi.org/10.1177/1756284818769074
Pan, Y., Liu, Y., Guo, H., Jabir, M. S., Liu, X., Cui, W., & Li, D. (2017). Associations between Folate and Vitamin B12 Levels and Inflammatory Bowel Disease: A Meta-Analysis. Nutrients, 9(4), 382. https://doi.org/10.3390/nu9040382
Siva, S., Rubin, D. T., Gulotta, G., Wroblewski, K., & Pekow, J. (2017). Zinc Deficiency is Associated with Poor Clinical Outcomes in Patients with Inflammatory Bowel Disease. Inflammatory bowel diseases, 23(1), 152–157. https://doi.org/10.1097/MIB.0000000000000989
Weisshof, R., & Chermesh, I. (2015). Micronutrient deficiencies in inflammatory bowel disease. Current opinion in clinical nutrition and metabolic care, 18(6), 576–581. https://doi.org/10.1097/MCO.0000000000000226