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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Hi, I am a Vietnamese Pharmacist. Our country's doctors recommend that: we should have sun exposure at the time of early morning (before 9a.m) and after 3a.m. Our city's latitude (Hanoi, Vietnam) is 21.07. And I ever said to some doctors about the best time of the day for sun exposure in summer (from 10 a.m-2h p.m), but they said " You are crazy. We learned from Medical University that the middle time is dangerous for skin. I want to know that if: – Have any public guiline of time of the day for sun exposure? – May you have some supports for me to apply latest updates of the time in my country. Thank you very much!

Ask the Vitamin D Council

Asked by  pharmhuong66719183600 on September 19, 2015

  • Amber Tovey
     Amber Tovey on

    Hi pharmhuong66719183600,

    That’s a great question. This topic poses quite the debate. However, the Vitamin D Council recommends sun exposure in moderation. We do not recommend that anyone burns or tans their skin; we recommend that people go out in the sun for about half the time that it takes for their skin to burn or tan. This may only be 10 minutes.

    As you may already know, vitamin D production is dependent on time of the day and your location. Therefore, things can get a little tricky when trying to determine the best time to receive sun exposure. We have a rule to make things simpler called the shadow rule. If your shadow is shorter than you are tall, then the sun is at the right angle for your body to make vitamin D (this is typically midday).

    I suggest taking a look at the sunshine calendar from the Vitamin D Day website. The calendar tells you an approximation of how much time you need in the sun to make adequate vitamin D dependent on the month and location. Here is the link: http://www.vitamindday.net/wp-content/uploads/2014/10/Sunshine-Calendar.pdf

    In addition, here is a link to the VDC’s first podcast that discusses the controversy regarding sun exposure along with recent research that has found benefits associated with sun exposure. https://www.vitamindcouncil.org/blog/vitamin-d-council-podcast-01-sun-exposure-and-health/

    I hope this somewhat helps. IAW provided some great resources and valuable information.



    • This reply was modified 1 year, 1 month ago by  Amber Tovey.
    Answered by  Amber Tovey on

  • IAW
     IAW on

    Please check back over the next week to see if there are other answers posted to your question.

    I would think the first thing you need to establish is that the current, minimum level for Vitamin D at 20ng/ml (50nmol/l) is far too low. We at the Vitamin D Council promote 50ng/ml (125nmol/l). Maybe the following information will help in that respect at http://www.vitamindcouncil.org/further-topics/for-health-professionals-position-statement-on-supplementation-blood-levels-and-sun-exposure/. An excerpt from this is “Regular and sensible sun exposure is a healthy practice.” “Significant vitamin D production occurs when your shadow is shorter than you are.”

    Next the following is one thing you could show them that comes from a study in Vietnam. “Maternal vitamin D status and infant outcomes in rural Vietnam: a prospective cohort study”. This can be found at http://www.ncbi.nlm.nih.gov/pubmed/24967813 or http://www.vitamindcouncil.org/blog/vitamin-d-status-during-late-pregnancy-may-relate-to-infant-language-development/. An excerpt from this is “It also illustrates the high prevalence of vitamin D deficiency in a region of abundant sunlight, highlighting the increasing importance that lifestyle and urban development have on vitamin D status.”

    Since you are closer to the equator, I am not sure how that factors in to the time of day for Vitamin D production. I am hoping someone else will answer that question. (I think it will still be 10-2 p.m.) At the latitude of 32 degrees in the USA, you can still make vitamin d in winter but you need to be out at 12:00p.m.for this to occur.

    Answered by  IAW on