Interview with MICHAEL HOLICK, M.D.

Michael Holick, M.D.


Andrew W. Saul Interviews Vitamin D Expert



“The population of the world has been brainwashed by the American Academy of Dermatology and the sunscreen industry, for 30 years, with the unrelenting message that you should never be exposed to direct sunlight because it is going to cause serious skin cancer and death.”

(Michael Holick, MD)


Editor’s 2006 introduction: Born 60 years ago in Jersey City, New Jersey, Michael Holick published his first scientific paper in 1970. Hundreds would follow, and now, he is arguably the world’s leading authority on vitamin D. Yet Dr. Holick’s advocacy of what he calls “sensible sun exposure” is so controversial that he was fired from Boston University Medical Center’s dermatology department. Controversy being no stranger to this Newsletter, we were pleased when Dr. Holick agreed to an interview, which follows in edited form.


DOCTOR YOURSELF NEWS: Dr. Holick, What are some of the research-based benefits of more vitamin D?


DR. MICHAEL HOLICK: You can reduce cancer risk by 30 to 50% by increasing vitamin D in the diet, or by sensible sun exposure. We gave mice colon cancer, and followed them for 20 days. Tumor growth was markedly reduced simply by having vitamin D in the diet. There was a 40% reduction in tumor size. And, casual sun exposure actually decreases your risk of melanoma. In Finland, back in the 1960’s, children that received 2,000 IU of vitamin D each day reduced their risk of getting Type 1 diabetes by 80%. Every tissue and every cell in your body has a receptor for vitamin D. Every tissue and every cell of your body requires vitamin D to function properly.


DY NEWS: Exactly how much vitamin D, and how much sun, do we need?


HOLICK: Vitamin D deficiency is less than 400 IU per day along with no sun exposure. If you take 400 IU daily, you would still have an inadequate amount of vitamin D. Humans need 1,000 IU each day, or to be exposed to sunlight. Five to ten minutes, arms and legs, three times a week, is adequate.


DY NEWS: What is you opinion of the official US RDA/DRI recommendations?


HOLICK: I was on the committee that set them (National Academy of Sciences, Panel on Calcium and Related Nutrients, 1996-1997). We have made some progress in increasing the recommendations. They are now 200 IU/day for children and adults up to age 50; 400 IU for adults over 50; and 600 IU/day for adults over 70.


DY NEWS: Would you have liked to have set the recommendations higher?


HOLICK: Yes. At the time, we were obligated to base our recommendations on the published literature before 1997. Based on new evidence, I think infants, up to one year of age, need 400 IU/day. Canada recommends 400 IU already. Then, from age one, and all through adulthood, I’d recommend 1,000 IU/day. Everyone needs 1,000 IU of vitamin D3 each day.


DY NEWS: And how are we doing?


HOLICK: In Boston, 50% of adolescent boys and girls are vitamin D deficient. 70% of moms and 80% their babies are vitamin D deficient at birth. These infants have no vitamin D stores, and the moms have none to give them.


DY NEWS: And that means rickets?


HOLICK: Rickets is only the tip of the vitamin D deficiency iceberg. If you are vitamin D deficient in childhood, you are 2.4 times more likely to develop Type 1 diabetes.


DY NEWS: And for people of color?


HOLICK: Skin pigment is a natural sunscreen. African American children require two to three times as much sun exposure, without sunscreen, to satisfy their requirement for vitamin D.


DY NEWS: What are the consequences of not getting enough sunlight?


HOLICK: If you live above 35 degrees north latitude, you are twice as likely to develop multiple sclerosis. Living in higher latitudes also means higher risk for Crohn's disease, rheumatoid arthritis, and high blood pressure.


DY NEWS: What are some examples of “high latitude” cities?


HOLICK: Anything above Atlanta, Georgia.


DY NEWS: I’ve been to Atlanta. To a Yankee like me, that’s pretty far south. Now you know I’m going to quote you on this. . .


HOLICK: That’s fine. Anywhere above about 35 or 37 degrees latitude, that is, anywhere north of Atlanta, Georgia, you basically cannot make vitamin D in your skin during the wintertime.


DY NEWS: And in the summer, should we tan?


HOLICK: I do not believe in tanning.


DY NEWS: That seems a rather moderate position.


HOLICK: I was fired from my position as Professor of Dermatology at Boston University Medical Center because I have been promoting sensible sun exposure, and had written the book, “The UV Advantage.” I had held that position for nearly ten years.


DY NEWS: Who fired you, and when?


HOLICK: Dr. Barbara Gilchrest, BU Medical Center Chief of Dermatology, in February 2004. She and I remain personal friends. I’m still full Professor of Medicine, Physiology, and Biophysics, and have been for 20 years. Dr. Gilchrest has been quoted as saying that to suggest that vitamin D deficiency is a significant health problem is “weak and absurd.” She has also been quoted as saying that linking vitamin D deficiency to medical illness is “schlock science.” I have never heard her rebut those statements.


DY NEWS: Were you fired entirely because of your stance on vitamin D and for no other reason?


HOLICK: No question about it. The American Academy of Dermatology is very uncomfortable about sensible sun exposure, and anyone who recommends it.


DY NEWS: You’re telling us that the American Academy of Dermatology does not believe in sensible sun exposure?


HOLICK: That is correct. They are believers in abstinence from all sun exposure. They have been pretty firm about this. In May 2004, three months after I was fired, I was asked to defend myself in front of all the staff.


DY NEWS: How successful was it?


HOLICK: I got people’s attention.


DY NEWS: Who is most opposed to you?


HOLICK: The “unenlightened” dermatologists of the American Academy of Dermatology.


DY NEWS: Yet it seems to be particularly difficult to kill yourself with vitamin D.


 HOLICK: True. One man took 1,000,000 IU of vitamin D per day, orally, for six months. Of course, he had the symptoms of severe vitamin D intoxication.


DY NEWS: But he lived to tell the tale?


HOLICK: Yes. His treatment was hydration (lots of water), and no more vitamin D or sunshine for a while. He’s perfectly happy and healthy. This was published in the New England Journal of Medicine. (Koutkia P, Chen TC, Holick MF. Vitamin D intoxication associated with an over-the-counter supplement. N Engl J Med. 2001 Jul 5;345(1):66-7.)


DY NEWS: How many people have died from vitamin D or other vitamins?


HOLICK: I have no experience of anyone dying from vitamin exposure. In thirty years, I’ve never seen it.


DY NEWS: And in the medical literature?


HOLICK: Not as far as I know.


DY NEWS: About how many people get too little vitamin D?


HOLICK: In the US and Canada, about 50%. About one billion people, worldwide, are vitamin D deficient. This is true even in sunny climates, because of lack of sun exposure.


DY NEWS: What advice do you wish to offer our readers?


HOLICK: The most important thing is to increase your vitamin D intake.


DY NEWS: What’s yours?


HOLICK: I take 1,100 IU of vitamin D every day.


DY NEWS: Do you use sunblock?


HOLICK: I do, but only after some sensible sun exposure.


DY NEWS: Do you wear a floppy hat?


HOLICK: Yes, after sensible sun exposure.


DY NEWS: You are one consistent person. So what’s the bottom line?


HOLICK: The population of the world has been brainwashed by the American Academy of Dermatology and the sunscreen industry, for 30 years, with the unrelenting message that you should never be exposed to direct sunlight because it is going to cause serious skin cancer and death. People are really quite surprised by the new message that sensible sun exposure, in moderation, is very important for good health. We should appreciate the sun for its benefits, and not abuse it.




Holick, MF and Jenkins, M.  The UV Advantage, iBooks: New York, 2004.

Saul AW. Vitamin D: Deficiency, Diversity and Dosage. Journal of Orthomolecular Medicine, 2003; Vol. 18, Numbers 3 and 4, p. 194-204. Posted at



“A PubMed database search yielded 63 observational studies of vitamin D status in relation to cancer risk, including 30 of colon, 13 of breast, 26 of prostate, and 7 of ovarian cancer, and several that assessed the association of vitamin D receptor genotype with cancer risk. The majority of studies found a protective relationship between sufficient vitamin D status and lower risk of cancer. The evidence suggests that efforts to improve vitamin D status, for example by vitamin D supplementation, could reduce cancer incidence and mortality at low cost, with few or no adverse effects.” (Garland CF, Garland FC, Gorham ED, Lipkin M, Newmark H, Mohr SB, Holick MF. The role of vitamin D in cancer prevention. Am J Public Health. 2006 Feb;96(2):252-61. Epub 2005 Dec 27.)   
”Inadequate photosynthesis or oral intake of Vitamin D are associated with high incidence rates of colorectal cancer . . . Prompt public health action is needed to increase intake of Vitamin D(3) to 1000IU/day, and to raise 25-hydroxyvitamin D by encouraging a modest duration of sunlight exposure.” (Gorham ED, Garland CF, Garland FC, Grant WB, Mohr SB, Lipkin M, Newmark HL, Giovannucci E, Wei M, Holick MF. Vitamin D and prevention of colorectal cancer. J Steroid Biochem Mol Biol. 2005 Oct;97(1-2):179-94. Epub 2005 Oct 19.)



“Vitamin D inadequacy has been reported in approximately 36% of otherwise healthy young adults and up to 57% of general medicine inpatients in the United States, and in even higher percentages in Europe. Recent epidemiological data document the high prevalence of vitamin D inadequacy among elderly patients . . . Supplemental doses of vitamin D and sensible sun exposure could prevent deficiency in most of the general population.” (Holick MF. High prevalence of vitamin D inadequacy and implications for health. Mayo Clin Proc. 2006 Mar;81(3):353-73.)    



”The conditions with strong evidence for a protective effect of vitamin D include several bone diseases, muscle weakness, more than a dozen types of internal cancers, multiple sclerosis, and type 1 diabetes mellitus. . . The current vitamin D requirements in the United States are based on protection against bone diseases. These guidelines are being revised upward in light of new findings, especially for soft-tissue health.” (Grant WB, Holick MF. Benefits and requirements of vitamin D for optimal health: a review. Altern Med Rev. 2005 Jun;10(2):94-111.) 


EXCELLENT (AND FREE) VITAMIN D E-NEWSLETTER is yours for the asking available from John Cannell and the Vitamin D Council: .


[You might also enjoy reading DOCTOR YOURSELF ( and FIRE YOUR DOCTOR! (]

Interview and comments copyright 2006 and prior years by Andrew W. Saul.


Andrew W. Saul


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