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.