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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.

Why does the Vitamin D Council recommend 5,000 IU/day?

Where did the Vitamin D Council get its recommendation that adults take 5,000 IU/day of vitamin D3 for the rest of their life? The Institute of Medicine’s Food and Nutrition Board say 600 IU/day is enough for adults and the Endocrine Society says 2,000 IU/day is enough for most adults.

We think the safest thing to do while all the research is going on is to maintain natural vitamin D levels. By natural, we mean those levels obtained by those with natural sun exposure, such as lifeguards, some roofers and gardeners, and others who work in the sun and expose a lot of skin to sunshine. This is how our ancestors behaved throughout our evolutionary history.

The best study that examined the vitamin D levels of people who get plenty of sun exposure was published last year. Researchers discovered that free-living hunter gatherers living around the African equator (where humans evolved) have average vitamin D levels of 46 ng/ml (115 nmol/L).

Luxwolda MF, Kuipers RS, Kema IP, Dijck-Brouwer DA, Muskiet FA. Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l. Br J Nutr. 2012 Nov 14;108(9):1557-61.

Most people will not have their blood tested unless their doctor recommends it. So we needed a recommended dose that:

  • Is easy to obtain at most pharmacies.
  • Will get at least 97% of people above 30 ng/ml.
  • Will get most people above 40 ng/ml, and close to around 50 ng/ml.
  • Will not cause anyone to get toxic levels.

When we decided on a recommendation with the four goals above in mind, we also had to take into account body weight. Besides genetics, body weight is the single biggest determinate of vitamin D levels. The more you weigh, the more vitamin D you need to take.

Professor Robert Heaney of Creighton University details in the study below just how high vitamin D supplementation/input needs to be to reach the vitamin D level goals above.

Drincic AT, Armas LA, Van Diest EE, Heaney RP. Volumetric dilution, rather than sequestration best explains the low vitamin D status of obesity. Obesity (Silver Spring). 2012 Jul;20(7):1444-8. doi: 10.1038/oby.2011.404.

Together with his coauthors, Professor Heaney stated that for a normal weight adult, 5,000 IU/day of total input was needed to obtain a vitamin D level of 40 ng/ml. Of course the final vitamin D level obtained by any dose depends on baseline level, sun exposure and genetics. But he was speaking of the average adult.

For those who want a more careful calculation, he stated his data showed that 70-80 IU/day/kg of body weight total input is needed to obtain a 25(OH)D of 40 ng/ml. That works out to about 35 IU/day/pound. So a 100 pound woman would need 3,500 IU/day of total input but a 300 pound lineman would need 10,500 IU/day. Keep in mind this is total input, which includes sunlight, diet and supplements.

Taking all these factors into account, we conclude a recommendation of 5,000 IU/day is about right for the average adult.

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.

4 Responses to Why does the Vitamin D Council recommend 5,000 IU/day?

  1. Rita and Misty says:

    This is a great explanation.

    I’m certain that this piece would be really helpful for those readers (including the social network readers like FB followers) who have yet to discover the benefits of a VDC membership.

    Be well !

  2. I am truly amazed at the results after people taking D3 supplements for one year. The truth is people are thanking me . If you guide people who want to feel better to the truth and let them decide if D3 is the answer the feed back will be a positive one. They crowds need to be educated, on how critical D3 is to overall health. A person I know started supplementing the right amount of D3 and k2, mg etc. And he seems to manage his c.o.p.d. so much better.

  3. Rita and Misty says:

    @[email protected],

    I commend you for your efforts, and I marvel at your great luck.

    I’m on my 2nd year of serious D talking…and I can tell you that getting people to adhere to supplementation is a big (huge) big problem. They stop before they are replete; and therefore, they don’t get to experience the remarkable healing powers of vitamin D.

    Because I am appropriately stubborn, I continue to outreach. But I must admit that even someone as persistent as me eventually tires (just a bit).

    Be well,

  4. Rogerio Luz Coelho says:

    Have been taking 10.000 UI for a year now … I am a Physician, so the risc is on me … And have never felt better, exercise and weight loss are EASIER. No sign of burnout or depression, feeling fine

    Am now at 79 ng/mL

    Cheers !!