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Vitamin D status and sun exposure in India

Background: Little if any cutaneous production of vitamin D(3) occurs at latitudes above and below 35° N and 35° S during the winter months. It was postulated that those residing in tropics synthesize enough vitamin D(3) year round. Several studies have documented the effect of latitude, season and...

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Autores principales: Harinarayan, Chittari V., Holick, Michael F., Prasad, Upadrasta V., Vani, Palavali S., Himabindu, Gutha
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Landes Bioscience 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897581/
https://www.ncbi.nlm.nih.gov/pubmed/24494046
http://dx.doi.org/10.4161/derm.23873
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author Harinarayan, Chittari V.
Holick, Michael F.
Prasad, Upadrasta V.
Vani, Palavali S.
Himabindu, Gutha
author_facet Harinarayan, Chittari V.
Holick, Michael F.
Prasad, Upadrasta V.
Vani, Palavali S.
Himabindu, Gutha
author_sort Harinarayan, Chittari V.
collection PubMed
description Background: Little if any cutaneous production of vitamin D(3) occurs at latitudes above and below 35° N and 35° S during the winter months. It was postulated that those residing in tropics synthesize enough vitamin D(3) year round. Several studies have documented the effect of latitude, season and time of the day on the cutaneous production of vitamin D(3) in an ampoule model. Studies from India have shown high prevalence of vitamin D deficiency despite abundant sunshine. Methods: We studied the influence of season and time of the day on synthesis of previtamin D(3) in an ampoule model in Tirupati, (latitude 13.40° N and longitude 77.2° E) south India, between May 2007 to August 2008. Sealed borosilicate glass ampoules containing 50 μg of 7-DHC in 1 ml of methanol were exposed to sunlight hourly from 8 a.m. until 4 p.m. The percent conversion of 7-DHC to previtamin D(3) and its photoproducts and the percent of previtamin D(3) and vitamin D(3) formed was estimated and related to solar zenith angle. Results: The percent conversion of 7-DHC to previtamin D(3) and its photoproducts and formation of previtamin D(3) and vitamin D(3) was maximal between 11 a.m. to 2 p.m. of the day during the entire year (median 11.5% and 10.2% respectively at 12.30 p.m.). Conclusions: Therefore at this latitude exposure to sunlight between the hours of 11 a.m. and 2 p.m. will promote vitamin D production in the skin year round.
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spelling pubmed-38975812014-02-03 Vitamin D status and sun exposure in India Harinarayan, Chittari V. Holick, Michael F. Prasad, Upadrasta V. Vani, Palavali S. Himabindu, Gutha Dermatoendocrinol Short Communication Background: Little if any cutaneous production of vitamin D(3) occurs at latitudes above and below 35° N and 35° S during the winter months. It was postulated that those residing in tropics synthesize enough vitamin D(3) year round. Several studies have documented the effect of latitude, season and time of the day on the cutaneous production of vitamin D(3) in an ampoule model. Studies from India have shown high prevalence of vitamin D deficiency despite abundant sunshine. Methods: We studied the influence of season and time of the day on synthesis of previtamin D(3) in an ampoule model in Tirupati, (latitude 13.40° N and longitude 77.2° E) south India, between May 2007 to August 2008. Sealed borosilicate glass ampoules containing 50 μg of 7-DHC in 1 ml of methanol were exposed to sunlight hourly from 8 a.m. until 4 p.m. The percent conversion of 7-DHC to previtamin D(3) and its photoproducts and the percent of previtamin D(3) and vitamin D(3) formed was estimated and related to solar zenith angle. Results: The percent conversion of 7-DHC to previtamin D(3) and its photoproducts and formation of previtamin D(3) and vitamin D(3) was maximal between 11 a.m. to 2 p.m. of the day during the entire year (median 11.5% and 10.2% respectively at 12.30 p.m.). Conclusions: Therefore at this latitude exposure to sunlight between the hours of 11 a.m. and 2 p.m. will promote vitamin D production in the skin year round. Landes Bioscience 2013-01-01 2013-01-01 /pmc/articles/PMC3897581/ /pubmed/24494046 http://dx.doi.org/10.4161/derm.23873 Text en Copyright © 2013 Landes Bioscience http://creativecommons.org/licenses/by-nc/3.0/ This is an open-access article licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. The article may be redistributed, reproduced, and reused for non-commercial purposes, provided the original source is properly cited.
spellingShingle Short Communication
Harinarayan, Chittari V.
Holick, Michael F.
Prasad, Upadrasta V.
Vani, Palavali S.
Himabindu, Gutha
Vitamin D status and sun exposure in India
title Vitamin D status and sun exposure in India
title_full Vitamin D status and sun exposure in India
title_fullStr Vitamin D status and sun exposure in India
title_full_unstemmed Vitamin D status and sun exposure in India
title_short Vitamin D status and sun exposure in India
title_sort vitamin d status and sun exposure in india
topic Short Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897581/
https://www.ncbi.nlm.nih.gov/pubmed/24494046
http://dx.doi.org/10.4161/derm.23873
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