Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Jan 1;5(1):177-80.
doi: 10.4161/derm.23351.

Vitamin D: Light side and best time of sunshine in Riyadh, Saudi Arabia

Fahad M Alshahrani  1 , Mussa H Almalki  2 , Naji Aljohani  2 , Abdullah Alzahrani  3 , Yousef Alsaleh  4 , Michael F Holick  5
Affiliations

Vitamin D: Light side and best time of sunshine in Riyadh, Saudi Arabia

Fahad M Alshahrani et al. Dermatoendocrinol. .

Abstract

Low levels of 25-hydroxyvitamin D have been documented among inhabitants of the wider Middle East and North African countries. Sunlight has long been recognized as a major provider of vitamin D. In this study we aimed to determine the optimum time for sun exposure in the Central region of Riyadh, Saudi Arabia. Ampoules containing 7-dehydrocholesterol in ethanol were exposed to sunlight every hour starting from sunrise until sunset in July and December. Our results demonstrated that the time of the day has a major influence in vitamin D production. In this study, summer production of previtamin D3 was observed to occur between 8:00 PM to 4:00 PM with peak hours between 10:00 AM to 12:00 PM. During wintertime however, the conversion began later at around 9:30 AM and ended sooner at 2:00 PM, with peak hours at 10:00 AM to 12 noon. In conclusion, the optimum time to get sun exposure for vitamin D3 production in Riyadh, during summer is from 9:00 AM and before 10:30 AM, as well as after 2:00 PM until 3:00 PM, while during winter it's from 10:00 AM until 2:00 PM. These times are important on a public health perspective, as it's free, relatively safe and the most enjoyable. This strategy is a highly efficacious way for improving the vitamin D status for children and adults and preventing vitamin D deficiency.

Keywords: Riyadh, Saudi; Vitamin D; exposure; sun; time.

PubMed Disclaimer

Figures

None
Figure 1. Conversion of 7-dehydrocholesterol (7-DHC) to previtamin D3, lumisterol and tachysterol at various times throughout the day in July on a sunny day in Saudi Arabia.
None
Figure 2. Conversion of 7-dehydrocholesterol (7-DHC) to previtamin D3, lumisterol and tachysterol at various times throughout the day in December on a sunny day in Saudi Arabia.
None
Figure 3. influence of season on the synthesis of previtamin D3 and its photoproducts (% total).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. DeLuca HF. Overview of general physiologic features and functions of vitamin D. Am J Clin Nutr. 2004;80(Suppl):1689S–96S. - PubMed
    1. Mawer EB, Hayes ME, Heys SE, Davies M, White A, Stewart MF, et al. Constitutive synthesis of 1,25-dihydroxyvitamin D3 by a human small cell lung cancer cell line. J Clin Endocrinol Metab. 1994;79:554–60. doi: 10.1210/jc.79.2.554. - DOI - PubMed
    1. Schwartz GG, Whitlatch LW, Chen TC, Lokeshwar BL, Holick MF. Human prostate cells synthesize 1,25-dihydroxyvitamin D3 from 25-hydroxyvitamin D3. Cancer Epidemiol Biomarkers Prev. 1998;7:391–5. - PubMed
    1. Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer? Int J Epidemiol. 1980;9:227–31. doi: 10.1093/ije/9.3.227. - DOI - PubMed
    1. Garland C, Shekelle RB, Barrett-Connor E, Criqui MH, Rossof AH, Paul O. Dietary vitamin D and calcium and risk of colorectal cancer: a 19-year prospective study in men. Lancet. 1985;1:307–9. doi: 10.1016/S0140-6736(85)91082-7. - DOI - PubMed

LinkOut - more resources