Why Does Vitamin D work?

Asthma sufferers may benefit more from inhaling vitamin D than the steroids usually prescribed for the condition.  And besides, aren’t we all concerned with side effects from steroids? A new study from the U.K. identifies a mechanism through which the vitamin can significantly reduce asthma symptoms and suggests it may offer a new method of treatment. The research was noted in Stone Hearth Newsletters.

The number of asthma cases has more than doubled since 1980, according to the National Institutes of Health. According to the Centers for Disease Control and Prevention, 18.9 million adults and 7.1 million children have asthma. Approximately 5,500 persons die from the condition each year, and rates have increased over the past 20 years.

The new study focused on IL-17A, a natural chemical the helps defend the body against infection but also tends to exacerbate asthma and reduce responsiveness to steroids when produced in large amounts. Researchers found that patients with asthma had much higher levels of IL-17A than those without asthma, and patients with steroid resistant asthma expressed the highest levels of IL-17A. Further research showed that vitamin D significantly reduced the production of IL-17A in cells from all patients studied.

“The results therefore demonstrate that vitamin D could potentially provide an effective add-on treatment for all asthma sufferers, reducing the amount of steroid-based medicines prescribed,” according to a release.

“These findings are very exciting as they show that vitamin D could one day be used not only to treat people with steroid resistant asthma but also to reduce the doses of steroids in other asthma patients, reducing the risk of harmful side effects,” said Catherine Hawrylowicz, lead researcher and King’s college professor.  “The results are so positive that we are testing this in a clinical trial in steroid resistant asthma patients to further research the possibilities of Vitamin D as a potential treatment.”  If Vitamin D is able to modulate potent mediators such as IL-17A, its effect on asthma sufferers could be quite dramatic. 

If this potential benefit is this strong for asthma, I wonder how Vitamin D can improve the health of your vocal cords?

The study, published this month in the Journal of Allergy and Clinical Immunology, adds to the body of research touting vitamin’s powers. Recent studies have suggested vitamin boosts immunityimproves muscles and is a key to healthy kidneys.

Here’s the full citation if interested.  J Allergy Clin Immunol. 2013 May 15. pii: S0091-6749(13)00526-5.
Enhanced production of IL-17A in patients with severe asthma is inhibited by 1α,25-dihydroxyvitamin D3 in a glucocorticoid-independent fashion.
Nanzer AM, Chambers ES, Ryanna K, Richards DF, Black C, Timms PM, Martineau AR, Griffiths CJ, Corrigan CJ, Hawrylowicz CM.

Source

MRC and the Asthma UK Centre for Allergic Mechanisms in Asthma, King’s College London, London, United Kingdom; Centre for Primary Care and Public Health, Blizard Institute, Queen Mary, University of London, London, United Kingdom.

Abstract

BACKGROUND:

TH17 cells are proposed to play a role in the pathology of asthma, including steroid-resistant (SR) disease. We previously identified a steroid-enhancing function of vitamin D in patients with SR asthma in restoring the impaired response to steroids for production of the anti-inflammatory cytokine IL-10.

OBJECTIVE:

We sought to investigate the production of the TH17-associated cytokines IL-17A and IL-22 in culture in patients with moderate-to-severe asthma defined on the basis of their clinical response to steroids and the susceptibility of this response to inhibition by steroids and the active form of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25[OH]2D3).

METHODS:

PBMCs were stimulated in culture with or without dexamethasone and 1,25(OH)2D3. A cytometric bead array, ELISA, and intracellular cytokine staining were used to assess cytokine production. The role of CD39 in inhibition of the TH17 response was studied by using quantitative real-time PCR, flow cytometry, and addition of the antagonist POM-1 to culture.

RESULTS:

Asthmatic patients synthesized much higher levels of IL-17A and IL-22 than nonasthmatic control subjects, with patients with SR asthma expressing the highest levels of IL-17A. Glucocorticoids did not inhibit IL-17A cytokine expression in patients and enhanced production in cultures from control subjects. Treatment with 1,25(OH)2D3 with or without dexamethasone significantly reduced both IL-17A and IL-22 levels. An antagonist of the ectonucleotidase CD39 reversed 1,25(OH)2D3-mediated inhibition of the IL-17A response.

CONCLUSION:

Patients with severe asthma exhibit increased levels of TH17 cytokines, which are not inhibited by steroids. 1,25(OH)2D3 inhibits TH17 cytokine production in all patients studied, irrespective of their clinical responsiveness to steroids, identifying novel steroid-enhancing properties of vitamin D in asthmatic patients.

Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

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