Dear Dr. Cannell:
I’ve been taking 2,000 – 5,000 IU of Vit D and when I was tested recently, it was only at 21. I live in New England, so there is not much sun although this summer, I sat outside in the sun for 20 mins once or twice a week. How can I get my level up?
I read that if you have gut dysbiosis, your body cannot absorb the Vit D. Is that true?
Without knowing how long you took 5,000 IU per day before your blood test, and without knowing when you went into the sun and with how much clothing, and what your baseline level was, it is difficult to answer your first question. It may be malabsorption, it may be a very low initial level, it may be genetics, it may be unproductive sun exposure, and it may be an error in the test.
For whatever reason, you are still apparently deficient and need to take 5,000 IU every day and test again in three months. Also, take your vitamin D with your largest meal of the day for better absorption. I have written some mixed advice in the past on whether you need to take with a meal, as the research is inconsistent. However, if you’re having malabsorption issues, there is no reason not to try taking vitamin D with largest meal of day.
I am unaware of any evidence that intestinal dysbiosis is associated with malabsorption of vitamin D, but I would be surprised if that were not the case. Dysbiosis (unhealthy imbalance in intestinal flora) is associated with a number of intestinal and immune maladies. As vitamin D is involved in signaling between the gut microbes and the immune system both, treating both dysbiosis (with probiotics and prebiotics) and your vitamin D deficiency may help your dysbiosis.
Ly NP, Litonjua A, Gold DR, Celedón JC. Gut microbiota, probiotics, and vitamin D: interrelated exposures influencing allergy, asthma, and obesity? J Allergy Clin Immunol. 2011 May;127(5):1087-94; quiz 1095-6. Epub 2011 Mar 21. Review.
Finally, please write again in three months with the results of your vitamin D blood test, so we know how you are doing.
John Cannell, MD