Allergy diseases are becoming more prevalent over the past decades. Atopy, the predisposition towards allergic diseases, is complex and occurs as a result of individual genetic susceptibility, exposure to surrounding environmental factors and nutritional factors. Those who are at risk of atopy, can suffer from conditions such as allergic rhinitis, allergic asthma, food allergy and atopic dermatitis.
Understanding the effect of environmental factors such as the effect of vitamin D, may potentially affect a person's development of allergy. This allows a window opportunity to manage or 'improve' the environmental causes, in hope of delaying or even halting the process of developing allergy.
What does Vitamin D do to our body?
Vitamin D is a vitamin that dissolve in fat. Vitamin D is found in 2 forms- vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). The liver processes vitamin D into 24-hydroxyvitamin D, which is further metabolised by the kidneys into an active from known as 1,25-dihydroxyvitamin D. Vitamin D acts through vitamin D receptors to regulate the levels of calcium and phosphate, which are two important bone minerals.
Interestingly, various immune cells have vitamin D receptors, allowing vitamin D to alter immune cells, control immune response and suppress inflammation. By regulating one's immune system, vitamin D is postulated to play a role in the onset and progression of allergy.
Atopic Dermatitis
In atopic dermatitis, one suffers a chronic, repeated inflammation of the skin. Common symptoms include itchy, dry and sensitive skin secondary to abnormal skin barrier function and possible further sensitization to environmental stressors.
Many medical research studies show vitamin D level inversely correlates to atopic dermatitis severity. Patients with lower levels of vitamin D appear to have more severe eczema. Vitamin D deficiency at birth is associated with higher risk of developing atopic dermatitis in infants. Expectedly, those with vitamin D supplementation (with baseline vitamin D deficiency) have better eczema control during winter months (where sun exposure- source of vitamin D, is minimal).
Allergic Asthma
Allergic asthma is a chronic, recurring inflammation of the airway leading to obstruction of breathing. One can present with recurring cough, wheezing, shortness of breath, chest tightness and difficulty in breathing.
Most medical studies suggest there is a link between vitamin D deficiency and asthma severity.
Vitamin D helps in remodeling the airway tissues in asthma. Vitamin D improves the function of smooth muscles of the lungs, aids lung function, reduces lung inflammation, changes immune response, even improves lung function response to steroid treatment (Steroid- is the backbone treatment in asthma condition), hence complements allergic asthma treatment!
During pregnancy, vitamin D is believed to play a role in fetal lung structure development. This suggests a possible impact on developing chronic lung diseases such as asthma in later life in those with vitamin D deficiency. Low vitamin D is also associated with respiratory infection in infants, which can subsequently increase the risk of developing asthma.
Intriguingly, the gut microbiome plays a role in the development of asthma. At the same time, vitamin D can affect both the gut and the lungs. Those with low vitamin D can have gut barrier dysregulation, leading to changed gut microbiome which can in turn affect the lung immune function, leading to risk of developing asthma.
Allergic Rhinitis
Allergic rhinitis patients present with repeated sneezing, snorty nasal fluid, blocked nose, itchy nose following exposure to certain inhaled allergens in the environment.
Most medical research reports that patients with allergic rhinitis tends to have lower vitamin D level compare to those without allergic rhinitis. However, the medical evidence on the correlation between vitamin D level and allergic rhinitis remains conflicting. The effect of vitamin D on allergic rhinitis can be confounded by other factors such as a person's age, gender, race and etc.
Food Allergies
Food allergy occurs when the body inadvertently recognizes the food protein as an allergen/ a dangerous protein and mount an exaggerated immune response against the food protein. Food allergy symptoms can affect various organs of the body- with respiratory, gut, skin symptoms. In severe cases, food allergy can cause anaphylaxis and death.
Although there is a postulated association of vitamin D deficiency and food allergies, the link remains unclear due to confounding factors such as gender, ethnicity, etc.
Effect of Vitamin D on Treatment Outcome of Allergy Conditions
Current systemic reviews and meta-analysis suggest that vitamin D supplement can be beneficial in reducing severity of atopic dermatitis and allergic rhinitis in children. In asthma children with vitamin D deficiency, vitamin D supplement may reduce asthma flare up as well, reducing the use of oral steroids or even hospitalization due to asthma exacerbation.
Sufficient vitamin D in pregnant mother can be potentially beneficial for infant from developing airborne allergies, asthma and allergic rhinitis- though medical evidence are inconclusive.
Potential Role of vitamin D and Immunotherapy
Allergen specific immunotherapy has been a useful desensitisation treatment for allergies towards house dust mites, grass, pollens, etc. Immunotherapy works by re-educating and re-challenging a person's immune system against a particular allergy to progressively reduce the exaggerated allergic response over time.
The challenges commonly faced in immunotherapy treatment include financial burden, years of medication compliance and commitment to achieve the full effect of immunotherapy.
Given the promising benefits of vitamin D in altering the body's immune response, vitamin D may possibly be used as an enhancer alongside with immunotherapy to improve the overall effectiveness.
What are the limitations of current medical research on vitamin D and allergy?
Current medical studies are generally not long enough in duration to see the long term effect of vitamin D. Furthermore, most studies can be biased due to small sized studies, studies that include a certain population, certain ethnicity, particular age group or gender. These confounding factors may affect the generalisation of the research outcomes. Also, the majority of the studies also do not factor in dietary intake of vitamin D or natural vitamin D sources such as the amount of sun exposure in the patients in the study groups. There is also no standardisation on the optimal dose of vitamin D required in alleviating or benefiting allergy conditions.
Take home message...
- Aside from genetic susceptibility, environmental factors and nutritional states such as vitamin D can play a role in the development of allergy.
- Vitamin D can modulate various immune cells, regulate both immune and inflammatory responses in the body.
- There is a correlation between vitamin D and severity of allergic conditions such as atopic dermatitis and asthma. One tends to fair better with atopic dermatitis and asthma when their vitamin D level is adequate.
- The link between vitamin D, allergic rhinitis and food allergies remains inconclusive.
- Prenatal vitamin D supplementation may benefit in preventing infant from airborne related allergies and atopy conditions- though more conclusive medical research is required to support it.
- Vitamin D can potentially be used as a complement treatment when a person is undergoing immunotherapy.
- Despite current medical research limitations, vitamin D, a low-cost and low-side effect micro mineral, shows increasingly indisputable benefit in allergy conditions and can be considered as a complement treatment when managing allergy.
Understanding the link between vitamin D and allergy disease can support better decisions for your health. At Dr Ben Medical, allergy immunotherapy treatment is available for patients who would like to discuss treatment options for managing allergy symptoms.
References:
- Zhang P, Xu Q, Zhu R. Vitamin D and allergic diseases. Front Immunol. 2024 Jul 4;15:1420883.
- Kawada K, Sato C, Ishida T, Nagao Y, Yamamoto T, Jobu K, Hamada Y, Izawa Ishizawa Y, Ishizawa K, Abe S. Vitamin D Supplementation and Allergic Rhinitis: A Systematic Review and Meta-Analysis. Medicina. 2025; 61(2):355.
- Hidayati AN, Sawitri S, Sari DW, Prakoeswa CRS, Indramaya DM, Damayanti D, Zulkarnain I, Citrashanty I, Widia Y, Anggraeni S. Efficacy of vitamin D supplementation on the severity of atopic dermatitis in children: A systematic review and meta-analysis. F1000Res. 2023 Sep 25;11:274.
- Giannetti A, Bernardini L, Cangemi J, Gallucci M, Masetti R, Ricci G. Role of Vitamin D in Prevention of Food Allergy in Infants. Front Pediatr. 2020 Aug 18;8:447.
- Ibrahim, H.M., El-Taieb, M.A., Hassan, M.H. et al. Relations between vitamin D3, total and specific IgE for house dust mites in atopic dermatitis patients. Sci Rep. 2020;10,21000.