Clinical decision-support only. For use by licensed dental professionals. Not a substitute for professional judgment or a complete drug reference. Always verify with primary sources.
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Vitamin

Vitamin B12

Likelihood in at-risk patientsModerate

Likelihood of deficiency within an at-risk group, not the general population.

Evidence confidenceHigh

Strength of the peer-reviewed evidence.

Food sources

Meat, poultry, fish, Eggs and dairy, Fortified nutritional yeast, Fortified plant milks (for vegans)

Typical intake: 2.4 mcg/day for most adults; higher-dose supplementation if on metformin or a PPI long-term. Confirm with the physician. Requires intrinsic factor for absorption.

Upper limit: No UL established: water-soluble with no well-documented toxicity from oral intake.

Dental & oral effects of deficiency

  • Smooth, sore or burning tongue (atrophic glossitis)

    A smooth, red, painful tongue with loss of papillae is a classic early oral sign of B12 deficiency.

  • Cracked, sore mouth corners (angular cheilitis)

    Cracking and inflammation at the corners of the mouth.

  • Recurring canker sores (recurrent aphthous ulcers)

    B12 deficiency is an under-recognized cause of recurrent canker sores.

  • Pale oral mucosa

    Generalized pallor of the gingiva and mucosa, alongside oral candidiasis risk, from impaired red-cell formation.

Associated with deficiency

  • Megaloblastic (pernicious) anemia: Impaired DNA synthesis in rapidly dividing cells, including oral mucosa.
  • Peripheral neuropathy: Numbness/tingling; can include oral paresthesia/burning mouth.

Dental & oral effects of surplus / excess

No well-established oral-specific effect of excess intake on file.

Sources

  1. Position of the Academy of Nutrition and Dietetics: oral health and nutrition. Touger-Decker R, Mobley C, Academy of Nutrition and Dietetics. Journal of the Academy of Nutrition and Dietetics, 2013.
  2. Vitamins and oral mucosal diseases: From bench to the bedside. Yesudian RI, Yesudian PD. Clinics in dermatology, 2026.
  3. Common Oral Conditions: A Review. Stoopler ET, Villa A, Bindakhil M, et al. JAMA, 2024.
  4. A Prescription for Change: Food as Medicine & the Vital Role of Nutrition in Patient Care. teethFirst. Continuing education course material, 2025.