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Where is our vitamin D coming from: Part 1

Posted on: April 5, 2013   by  John Cannell, MD


How much vitamin D comes from food, and how much vitamin D comes from sunlight? For most of the past 20 years, we were told that 90% of our vitamin D comes from skin production, given adequate full body sun exposure. For most members of the Vitamin D Council, who usually sunbathe or take 5,000 IU/day, the following paper is of academic interest only. It only applies to those who live the normal indoor life and do not adequately supplement, which is more than 90% of the population.

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5 Responses to Where is our vitamin D coming from: Part 1

  1. [email protected]

    I see many questions concerning the relationship of Vitamin D and Calcium as affected by vitamin K2. Some indication that heart and arteries may be cloged if Vitamin D and Calcium intake is high with our the vitamin K2 to aid in proper absorption into bones rather than heart valves and arteries. Is there any information you can make available on this subject?

    William D. Bassett

  2. SteveGilroy

    I can attest to your last comment in your article. As an indoor tanner in Canada my levels are at around 45ng/ml and I supplement with a multi vitamin that includes 400IU of vitamin D. I’ve been on the GrassRootsHealth research project for 5 years now. The first 2 years I stopped indoor tanning for spring and summer to see what would happen to my vitamin D blood levels. My vitamin D levels dropped 47%. UVB light is still the best place to get your vitamin d.

  3. Rita and Misty


    I share with you one of my favorite journal articles on the benefits of sunlight. I hope you enjoy it as much as I always do. It is an oldie but a goodie, for sure. I refer to it often.

    Be well! 🙂

    Environ Health Perspect. 2008 April; 116(4): A160–A167.
    PMCID: PMC2290997
    Benefits of Sunlight: A Bright Spot for Human Health
    M. Nathaniel Mead


  4. allometric24

    I suggest going to the following sites for K2 info.
    yourhealthbase.com March issue and http://www.vitaminK2.org

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