Dr. Michael F. Holick, Ph.D., M.D.
Dr. Michael F. Holick

Cancer and Vitamin D

Posted by admin on under Cancer, Vitamin D | 8 Comments to Read



As early as 1941, it was observed that people living at higher latitude were at higher risk of dying of cancer.  In the 1980’s and the 1990’s, several reports surfaced revealed that living at higher latitude and being at higher risk of vitamin D deficiency increased risk of developing and dying of cancers of the colon, rectum, prostate, breast, ovary.  More recently, vitamin D deficiency has been associated with increased risk of developing many other cancers including cancer of the esophagus, pancreas and leukemia.   Read more of this article »


Posted by admin on under Obesity, Vitamin D | 16 Comments to Read

Obesity is associated with vitamin D deficiency.  The reason is that the vitamin D is trapped within the fat and cannot easily exit.  As a result, obese patients need at least twice as much vitamin D as a normal weighted individual in order to maintain a normal vitamin D status with a 25(OH)D between 30-60 ng/ml.    

Wortsman J, Matsuoka LY, Chen TC, Lu Z, Holick MF. Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr 2000;72: 690-693. 


Vitamin D2 vs. D3

Posted by mfholick on under Vitamin D | 12 Comments to Read

Vitamin D2 and Vitamin D3 Are They Equally Potent?

During the past several years, there have been two studies Trang et al, (Am J Clin Nutr 68:854-858, 1998); and Armas et al, (J Clin Endocrinol Metab 89:5387-91; 2004) that have raised questions about whether vitamin D2, which is found in some supplements, used in some fortified foods and is the pharmaceutical form of vitamin D that doctors prescribe for their patients, is as effective as vitamin D3 in maintaining a person’s vitamin D status, i.e., blood level of 25-hydroxyvitamin D.  Trang et al 1998 gave healthy adults Read more of this article »

Vitamin D Status

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I typically prescribe 50,000 IU of vitamin D2 once a week for eight weeks to fill the empty vitamin D tank. Since patients present with vitamin D deficiency, treatment will not prevent reoccurrence, and, therefore, after correcting their vitamin D deficiency, I place patients on 50,000 IU of vitamin D2 once every two weeks forever. I have reviewed my medical charts and patients who have been on this program for up to 64 months continue to remain vitamin D sufficient with blood levels of 25-hydroxyvitamin D between 30 and 90 ng/ml. 

An alternative method is to purchase a vitamin D supplement from a reputable manufacturer and to take 2,000 to 4,000 IU of vitamin D a day for 60 days to correct the vitamin D deficiency. To maintain vitamin D sufficiency, a minimum of 1,000 IU of vitamin D a day is necessary for both children and adults. Our recent data suggests in the winter in Boston that 1,000 IU of vitamin D a day was still unable to raise blood levels above 30 ng/ml, and, thus, in the winter when the sun is unable to provide any vitamin D, ingesting 2,000 IU of vitamin D a day should be effective in maintaining a normal serum 25-hydroxyvitamin D above 30 ng/ml.

The one caution is that patients with any type of chronic granulomatous disorder such as sarcoidosis, tuberculosis, histoplasmosis, etc. need to be maintain their 25(OH)D levels between 20 and 30 ng/ml otherwise the granulomatas can activate vitamin D resulting in an increase in the urine and blood calcium levels. You should seek a physician’s advice about this. 

Holick, M.F. Resurrection of vitamin D deficiency and rickets. J Clin Invest 2006, 116(8):2062-2072.

Holick, MF. Vitamin D Deficiency. N Engl J Med 2007;357:266-281.

Holick, MF, et al. Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D. JCEM December 18, 2007 [Epub ahead of print].

Malabanan A., Veronikis I.E., Holick M.F. Redefining vitamin D insufficiency. Lancet 1998; 351: 805-806.

A 65 year old female with osteopenia

Posted by admin on under Case Files | 3 Comments to Read

I was referred a 65 year old white female who on bone mineral density analysis was found to be osteopenic and had a history of 2” height loss.  She entered menarche at the age of 13 and had regular periods until menopause at the age of 52.  She was on hormone replacement therapy and developed breast cancer at the age of 61.  She underwent lumpectomy and radiation therapy, and initially was put on tamoxifen and placed on an aromatase inhibitor for the past four years.  She has limited her calcium intake because of concerns about vascular calcification and kidney stones.  There was no previous history of premature graying (which can increase risk of having osteopenia and osteoporosis) nor was there a history of kidney stones.   Read more of this article »

Welcome to VitaminDHealth.org

Posted by mfholick on under Vitamin D | 95 Comments to Read

 Michael F. Holick, PhD, MD
 Professor of Medicine, Physiology and Biophysics
 Director of the General Clinical Research Center
 Director of the Vitamin D, Skin and Bone Research Laboratory
 Director, Biologic Effects of Light Research Center
 Boston University Medical Center

               Help spread the word about Vitamin D deficiency in 2013:

Dr. Holick’s new book The Vitamin D Solution is now available! Click on the book cover for more information on how to order.

Vitamin D is not a vitamin but a hormone. It is unique in that it is made in the skin as a result of exposure to sunlight. Photosynthesis of vitamin D has been occurring on earth for more than 750 million years. Some of the earliest life forms that were exposed to sunlight for their energy requirement were also photosynthesizing vitamin D. Both children and adults have in the past depended on adequate sun exposure to satisfy their vitamin D requirement. It is well documented that at the turn of the last century upwards of 80% of children in the industrialized, polluted cities of northern Europe and northeastern United States suffered from the devastating consequences of vitamin D deficiency rickets. The skin has a large capacity to make vitamin D. Exposure of a person in a bathing suit to a minimal erythemal dose of sunlight, which is typically no more than 15-20 minutes on Cape Cod in June or July at noon time, is the equivalent to taking 20,000 IU of vitamin D orally. It is now well documented that in the absence of any sun exposure 1,000 IU of vitamin D3 a day is necessary to maintain healthy levels of 25-hydroxyvitamin D in the circulation. An analysis of the NHANES III data has demonstrated that neither children nor adults are receiving an adequate amount of vitamin D from their diet or from supplements.

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