Understanding What Vitamin Deficiency Causes Recurrent Aphthous Stomatitis

October 22, 2025 •

4 min read

Affecting up to 25% of the global population, recurrent aphthous stomatitis (RAS) can be a painful and frustrating condition. While its exact cause remains elusive, a significant body of research points toward specific nutritional shortfalls as a predisposing factor. For those wondering what vitamin deficiency causes recurrent aphthous stomatitis, the answer often involves a closer look at key hematinics and other vital micronutrients essential for oral mucosal health.

Quick Summary

Nutritional deficits, including vitamin B12, folate, iron, and vitamin D, can be contributing factors in recurrent aphthous stomatitis (RAS). Addressing these underlying deficiencies through proper diet or supplementation may help reduce the frequency and severity of canker sores. An accurate diagnosis and effective management strategy for RAS requires a comprehensive nutritional and medical evaluation.

Key Points

Vitamin B12 Deficiency: Low levels of vitamin B12 can impair cellular repair in the oral mucosa, increasing the risk of recurrent aphthous stomatitis (RAS).
Folate (B9) Deficiency: Inadequate folate can disrupt epithelial cell renewal, a process vital for a healthy mouth lining and potentially contributing to RAS.
Iron Deficiency: Iron is necessary for proper epithelial cell growth and oxygen transport; a deficiency can lead to mucosal atrophy and make the mouth more susceptible to ulcers.
Vitamin D's Role: Emerging evidence suggests that low serum vitamin D levels may be a risk factor for RAS due to its involvement in immune function and mucosal health.
Diagnosis is Key: Blood tests are recommended to identify specific nutritional deficiencies before initiating supplementation, as effective treatment depends on correcting the exact imbalance.
Comprehensive Approach: Managing RAS often involves a multifactorial strategy that includes dietary adjustments, supplementation, and addressing other triggers like stress and trauma.

The Connection Between Nutritional Deficiencies and RAS

Recurrent aphthous stomatitis (RAS), commonly known as canker sores, is characterized by painful, recurring ulcers in the mouth. While a definitive single cause has yet to be identified, research suggests that it is a multifactorial condition influenced by genetics, immune function, stress, and, importantly, nutritional status. Deficiencies in certain vitamins and minerals, often referred to as hematinics, can compromise the integrity of the oral mucosa, making it more susceptible to ulceration. When the epithelial lining of the mouth is weakened, minor trauma or other triggers can more easily result in the characteristic lesions of RAS.

Several studies have noted a higher prevalence of nutritional deficiencies in patients with RAS compared to the general population. The presence of an underlying deficiency may allow an existing tendency for ulceration to manifest more frequently or severely. Conversely, correcting these shortfalls through replacement therapy has been shown in some cases to lead to a significant reduction or even complete remission of aphthous ulcers. This highlights the critical role that proper nutrition plays in managing and potentially preventing the recurrence of these painful lesions.

Key Vitamin and Mineral Deficiencies Implicated in RAS

Vitamin B12 (Cobalamin)

Vitamin B12 is essential for DNA synthesis and the formation of red blood cells, as well as maintaining proper neurological function. A deficiency in B12 can impair cellular repair and mucosal integrity, leading to an increased susceptibility to oral ulcers. Research has linked low serum B12 levels to the prevalence of RAS. Studies have explored the effects of vitamin B12 in managing RAS symptoms. Possible causes of B12 deficiency include dietary inadequacy (especially for vegetarians and vegans), malabsorption issues like pernicious anemia, and other gastrointestinal conditions.

Folate (Vitamin B9)

Folate works closely with vitamin B12 in DNA and RNA synthesis, supporting the rapid cell turnover needed for a healthy oral mucosa. A lack of folate can disrupt this renewal process, potentially contributing to the formation of oral ulcers. Studies have indicated that patients with RAS may have lower dietary intake and blood levels of folate compared to control groups. Conditions affecting nutrient absorption, such as celiac disease or inflammatory bowel disease, can also lead to folate deficiency.

Iron and Ferritin

Iron is crucial for numerous bodily functions, including cellular respiration, energy production, and the proper growth and function of epithelial cells. A deficiency can lead to anemia, which reduces the oxygen-carrying capacity of the blood and can cause atrophy of the oral epithelium, making it vulnerable to ulceration. Some studies have found lower levels of serum iron and ferritin (an iron-storage protein) in patients with RAS. Correcting iron deficiency anemia can lead to improvement in RAS symptoms for some individuals.

Vitamin D

Emerging evidence suggests a link between low serum vitamin D levels and an increased risk of RAS. Vitamin D plays a crucial role in regulating immune responses, and its deficiency has been associated with various autoimmune and dermatological diseases. Several meta-analyses have found significantly lower vitamin D levels in RAS patients compared to healthy individuals. While the exact mechanism is not fully understood, it is thought to involve vitamin D's influence on the innate and acquired immune systems and its role in maintaining mucosal health.

The Role of Diet and Malabsorption in RAS

Inadequate dietary intake is a common cause of nutritional deficiencies that can trigger RAS. Those on restrictive diets, particularly vegetarian or vegan diets, are at higher risk for vitamin B12 deficiency since it is primarily found in animal products. However, deficiencies are not limited to specific diets and can also result from poor overall nutritional habits. Malabsorption conditions are another significant factor. Celiac disease, Crohn's disease, and other intestinal disorders can prevent the body from properly absorbing key nutrients, even when they are present in the diet. For this reason, comprehensive diagnostic testing is essential to uncover the root cause.

Diagnosis and Management

Proper management of RAS requires an accurate diagnosis of any underlying nutritional deficiencies. This is best achieved through a consultation with a healthcare professional, who can order specific blood tests to measure levels of B12, folate, iron, ferritin, and vitamin D. If deficiencies are identified, the healthcare provider may recommend dietary changes and/or supplementation. For severe cases or malabsorption issues, other interventions may be necessary.

Comparison of Key Nutritional Deficiencies and RAS


Nutrient	Role in Oral Health	Potential Impact on RAS	Food Sources
Vitamin B12	DNA synthesis, cell repair, mucosal integrity	Impairs mucosal healing, increases ulcer risk	Meat, fish, eggs, dairy, fortified cereals
Folate (B9)	Cell renewal, DNA repair	Disrupts epithelial cell turnover	Leafy greens, legumes, whole grains
Iron	Epithelial growth, oxygen transport	Causes mucosal atrophy, increases vulnerability	Red meat, poultry, beans, lentils, spinach
Vitamin D	Immune function modulation, tissue repair	Compromises immune response and mucosal integrity	Fatty fish, fortified milk, sunlight

Conclusion

While recurrent aphthous stomatitis is a complex condition with multiple potential triggers, addressing nutritional deficiencies is a crucial step in its management. Deficiencies in vitamins like B12, folate, and D, as well as minerals like iron, have been consistently linked to the onset and severity of oral ulcers. By identifying and correcting these underlying nutritional shortfalls through a balanced diet or targeted supplementation, many individuals can experience a significant reduction in the frequency and pain associated with canker sores. For those struggling with persistent RAS, a comprehensive nutritional evaluation by a healthcare provider offers a pathway toward effective relief and improved oral health.

Understanding Nutritional Deficiencies and Recurrent Aphthous Stomatitis

Frequently Asked Questions

While multiple deficiencies can contribute, vitamin B12 is one of the most frequently cited in research studies. Other key deficiencies include folate (vitamin B9) and iron.

For some individuals, correcting an underlying nutritional deficiency can significantly reduce the frequency, duration, and severity of aphthous ulcers, and in some cases, lead to complete remission.

RAS is multifactorial. Other potential causes include local trauma, stress, genetic predisposition, immune system abnormalities, hormonal changes, and food sensitivities.

A healthcare professional can order blood tests to check your levels of key hematinics and vitamins, such as B12, folate, iron, and vitamin D. This is the most reliable way to confirm a deficiency.

No. While supplementation is a direct way to address a deficiency, dietary modifications are also important. For underlying malabsorption issues, a healthcare provider may recommend additional interventions.

Not all cases of RAS are linked to nutritional deficiencies. A significant percentage of patients have an idiopathic form where no specific cause is identified.

Ensuring a diet rich in B vitamins, iron, and vitamin D can help. This includes consuming meat, eggs, dairy, leafy greens, legumes, and fortified foods. Identifying and avoiding food allergens may also be beneficial.