Vitamin D Newsletter


Increased Body Fat? More 'D' Needed

Doctor Philippe from Paris writes:

Dr. Cannell: I'm a physician and many of my patients have difficulty getting a normal 25(OH)D, even with 4,000 Units per day over 4 months. Did you read anything about resistance to vitamins D supplementation? Thank you for all your work. A bit of good news: in France the labs have put up the normal level of blood vitamins D from 20 ng/ml to 30 ng/ml.

Dr. Cannell replies:

The resistance is probably due to the relatively low dose and patient's body fat. Many larger adults need 5,000–10,000 IU  per day to get adequate levels. I'm glad they have increased the lower limit in France. However, it should be 40 and not 30. Remember Bruce Hollis, in a crucial paper, showed that the kinetics of vitamin D's metabolism is not normalized until levels are above 40 and often 50. His discovery is compelling evidence that levels of 40–50 represent the lower limit of the ideal human range.

Page last edited: 10 August 2010