Can SIBO cause vitamin deficiencies?

Yes, SIBO commonly causes vitamin deficiencies because the bacterial overgrowth in the small intestine consumes essential nutrients before your body has a chance to absorb them. This is particularly true for Vitamin B12; SIBO bacteria actively consume B12-intrinsic factor complexes, making them unavailable for absorption. Additionally, the excess bacteria deconjugate bile acids, which impairs the digestion and absorption of dietary fats and fat-soluble vitamins (A, D, E, and K). Iron deficiency is also highly common, driven by localized mucosal inflammation and the fact that bacteria feed on dietary iron. If you suspect these nutritional gaps are affecting your health, read about the full range of [SIBO symptoms](/sibo-symptoms) to identify other warning signs.

Disclaimer: This content is reviewed and fact-checked by Daryl Stubbs, Certified Holistic Nutritional Consultant (C.H.N.C), for educational purposes. It does not constitute medical advice or a doctor-patient relationship.