South Korean Researchers Say Vitamin D Deficiency Can Cause Allergic Rhinitis, Suggest Moderate Exposure To The Sun To Reduce Vulnerability

A team of researchers at Seoul National University Hospital have a link between vitamin D deficiency and allergic rhinitis, which is a common allergy during autumn.

According to a study led by Prof. Kang Hye Ryun at Seoul National University Hospital, the likelihood of experiencing allergic rhinitis increases by 80.6 percent in people who have low levels of vitamin D, Korea Times writes Oct. 4.

Allergic rhinitis is a hypersensitive reaction to antigens such as pollen, fungus, animal hair, or dust mites.

Chosun Ilbo reports Thursday patients suffering allergic rhinitis experience spasmodic coughing, blocked nose, sneezing and clear nasal discharge. They also complain of itchy eyes, sore throat, headache, and problems involving smelling.

Cases of allergic rhinitis have seen a steady increase since 1960, also due in part to environmental pollution.

Kang's study analyzed the correlation between levels of vitamin D and allergic rhinitis in 8,012 adults. The results show that 11.1 percent of respondents who had lower levels of vitamin D had allergic rhinitis. Lower levels of vitamin D showed a higher corresponding ration of allergic rhinitis in patients. More specifically, those with less than 15ng/mL vitamin D in their blood had 80.5 percent more incidence of allergic rhinitis as compared to those with at least 25ng/mL vitamin D.

"Vitamin D has been shown to inhibit differentiation, maturation, activation and survival of dendritic cells, leading to impaired T-cell activation," the researchers states in their paper.

They add, "Recent studies have reported that patients with asthma have lower serum Vitamin D levels than normal individuals, and extremely low levels have been related to severe asthma and more frequent exacerbations. An association between Vitamin D deficiency and atopic dermatitis also has been reported."

Kang also suggests that moderate exposure to the sun could help lessen a person's vulnerability to allergic rhinitis.

"We get most of our Vitamin D through the sun, but staying indoors and too much use of sunscreen may lead to insufficient levels of it. In fact, many Koreans have low vitamin D levels," Kang says.

Kang adds that exposure for at least 20 minutes between 10a.m. to 2p.m. is generally sufficient.