Mouth pain? All due to vitamin D deficiency

In brief

• The sensation of burning or tingling in the tongue and mouth (burning mouth syndrome, BMS or glossodynia) can have multifactorial causes: local iatrogenic, metabolic, neurological, and psychological.
• Clinical studies and reviews have found that a proportion of patients with BMS have low vitamin D levels, but the evidence does not definitively prove that the deficiency is the primary cause of oral pain.
• Vitamin D is important for bones, muscles, and certain aspects of immune function; the association with oral symptoms is plausible but remains largely observational.
• Clinical evaluation of BMS requires screening for local and systemic causes (including blood tests) and a multidisciplinary approach; correction of any deficiencies can be considered in the clinical context, not as a guaranteed treatment for pain.

Abstract: what does science say?

Burning Mouth Syndrome (BMS) is a chronic intraoral pain characterized by burning, tingling, or altered taste, often without objective clinical signs. Recent literature shows that a significant percentage of patients with BMS present altered blood test results, including reduced levels of 25-hydroxyvitamin D. However, most available evidence is observational or descriptive: cohort studies, case-control studies, and narrative reviews report associations, while the quality and heterogeneity of research limit causal inferences. There are also extensive reviews on the importance of vitamin D for bone health, muscle function, and immunological modulation; solid evidence regarding fracture prevention indicates benefits when vitamin D and calcium are administered together in selected populations. For BMS, evidence of the effectiveness of vitamin supplementation as a primary treatment for oral pain remains scarce. In summary: vitamin D deficiency is a plausible factor observed in subsets of patients with oral burning, but it cannot be considered the sole cause of the disorder in the absence of robust experimental data.

What is Burning Mouth Syndrome (BMS)?

BMS is defined as a chronic burning or discomfort sensation in the mouth, often localized to the tip or edges of the tongue, lips, or palate, typically lasting hours per day for months. It can be classified as primary (idiopathic) or secondary when local or systemic causes can be identified. Prevalence is higher in women in peri- and post-menopausal age.

What evidence links vitamin D and oral symptoms?

Several observational clinical studies and reviews report that a proportion of patients with BMS have hypovitaminosis D compared to control populations or reference thresholds. These studies report associations but differ in design, sample, and diagnostic criteria, which makes it prudent to interpret the results as indications of association rather than proof of causality.

What it means in practice

For a person experiencing burning, numbness, or tingling in the tongue and mouth, it is helpful to know that clinical evaluation is the first step. The doctor or dentist will assess the history, medications, presence of irritating prostheses or restorations, and potential local causes. The doctor may suggest laboratory investigations to rule out known systemic conditions associated with oro-facial symptoms: vitamin deficiencies (B12, folate, iron), alterations in calcium or vitamin D metabolism, thyroid disorders, diabetes, and opportunistic infections.

If tests show a documented vitamin D deficiency, correction (through controlled sun exposure, diet, or supplementation under clinical supervision) may be indicated for general health reasons: bone health, muscle function, and potential immunomodulatory effects [4][6][7]. However, normalization of vitamin D levels alone does not guarantee resolution of oral burning: studies on BMS are heterogeneous, and evidence of direct therapeutic efficacy of supplementation is limited [1][3].

In practice, the most prudent approach is this: consider searching for secondary causes in the presence of BMS; treat documented nutritional deficiencies for known systemic benefits; integrate the approach with specialist evaluations (dentistry, internal medicine, neurology, psychology) when indicated. The decision on supplementation must be personalized, based on laboratory values, risk factors, and patient preferences, and carried out under medical supervision [1][3][4].

Key points to remember

• BMS is a complex and multifactorial clinical condition: there is no single cause common to all patients.
• Several studies have found an increased prevalence of low vitamin D levels among BMS patients; this suggests an observational association but does not prove causality [1][2][3].
• Vitamin D has established roles in bone metabolism, muscle function, and in modulating certain immunological aspects; these roles are relevant for general health and for groups at risk of hypovitaminosis [4][6][7].
• Vitamin D supplementation interventions show documented benefits for some outcomes (e.g., reduction in fracture risk, especially when combined with calcium) but there is no robust evidence that supplementation directly cures the oral pain of BMS [4][5].
• The clinical management of BMS requires a comprehensive diagnostic approach: evaluating local causes, reviewing medications, considering blood tests, and specialist consultations; correcting deficiencies must be integrated into this multidisciplinary context [1][3].

Limitations of the evidence

The literature on the association between vitamin D and oral burning is largely composed of observational studies, case reports, and narrative reviews: these designs can detect associations but do not demonstrate causal effects. The main limitations include sample size and selection, heterogeneous definitions of BMS, absence of standardized exposure measures, and variable thresholds for defining vitamin D deficiency. Randomized clinical trials evaluating supplementation specifically for BMS are scarce or absent; for this reason, therapeutic recommendations must remain cautious and personalized [1][2][3].

Editorial Conclusion

The comparison between clinical data and biological knowledge indicates that vitamin D deficiency is observed in a portion of patients with burning mouth syndrome, but the relationship is not sufficient to support absolute causal or therapeutic claims. Vitamin D is fundamental for systemic health, and its supplementation, when indicated by tests, can lead to established benefits (for example, in the prevention of certain fractures along with calcium). However, in the context of BMS, management should be holistic: diagnosing and treating any secondary causes, offering multidisciplinary specialist support, and considering the correction of documented deficiencies as part of a broader clinical pathway. Clear communication with the patient remains fundamental: explaining that normalizing vitamin levels is a general health goal, not a guarantee of immediate resolution of oral pain. Future research requires controlled clinical studies to evaluate if, how much, and in which subgroups the correction of hypovitaminosis D can affect BMS symptoms [1][3][4].

Editorial Note

This article has been updated to integrate available scientific evidence and improve clarity and transparency. The information provided is for informational purposes only and does not replace the advice of your treating physician. In case of persistent symptoms, consult a healthcare professional.

Scientific research

1. Burning mouth syndrome: results of screening tests for vitamin and mineral deficiencies, thyroid hormone, and glucose levels—experience at Mayo Clinic over a decade. International Journal of Dermatology. https://doi.org/10.1111/ijd.13634 [DOI verified]
2. Hypovitaminosis D, objective oral dryness, and fungal hyphae as three precipitating factors for a subset of secondary burning mouth syndrome. Heliyon. https://doi.org/10.1016/j.heliyon.2023.e19954 [DOI verified]
3. Micronutrients status as a contributing factor in secondary burning mouth syndrome: a review of the literature. Health Science Reports. https://doi.org/10.1002/hsr2.1906 [DOI verified]
4. Vitamin D and Calcium for the Prevention of Fracture: A Systematic Review and Meta-analysis. JAMA Network Open. https://doi.org/10.1001/jamanetworkopen.2019.17789 [DOI verified]
5. Association Between Calcium or Vitamin D Supplementation and Fracture Incidence in Community‑Dwelling Older Adults: A Systematic Review and Meta‑analysis. JAMA. https://doi.org/10.1001/jama.2017.19344 [DOI verified]
6. Vitamin D Regulation of Immune Function. The Journal of Clinical Investigation. https://doi.org/10.1172/JCI137244 [DOI verified]
7. Vitamin D and immune function: an overview. Nutrients. https://doi.org/10.3390/nu5072502 [DOI verified]
8. Trends of burning mouth syndrome: a bibliometric study. Frontiers in Neurology. https://doi.org/10.3389/fneur.2024.1443817 [DOI verified]
9. Effect of Vitamin D Supplementation on Risk of Fractures and Falls According to Dosage and Interval: A Meta-Analysis. Endocrinology and Metabolism (EnM). https://doi.org/10.3803/EnM.2021.1374 [DOI verified]