We all have an intestinal microbiome. It is the totality of the intestinal microflora living in our intestines, such as bacteria, viruses, fungi and other living creatures. It also includes the genetic composition of the microflora and their interactions with the body, especially the immune system. It has been shown that microbiome serves important functions in immunity, inflammatory signaling, metabolism, and maintenance of normal barrier functions.
A dysregulated or dysfunctional microbiome (a condition termed dysbiosis) has been implicated in obesity, diabetes, inflammatory bowel disease, irritable bowel syndrome, and colorectal cancer. There is evidence that decreased vitamin D intake may be associated with changes to the microbiome. The vitamin D receptor in the gut has been shown to be critical in regulating intestinal function, preventing pathogenic bacterial invasion, inhibiting inflammation and maintaining cell integrity.
A probiotic is a hopefully benign bacterium that is supposed to help dysbiosis by instilling beneficial bacteria into the intestine.
So what’s new about that? What’s new is that a group of scientists at McGill University in Canada have discovered that one can raise vitamin D levels by giving patients a probiotic.
Jones ML, Martoni CJ, Prakash S. Oral supplementation with probiotic L. reuteri NCIMB 30242 increases mean circulating 25-hydroxyvitamin D: a post-hoc analysis of a randomized controlled trial. J Clin Endocrinol Metab. 2013 Apr 22.
The authors, Doctor Mitchell Lawrence Jones working with senior author Doctor Satya Prakash, did a secondary analysis of their randomized controlled trial of a Lactobacillus probiotic or placebo in 127 patients. They measured the serum levels of several fat soluble vitamins before and after the intervention.
While they found no differences in the blood levels of other vitamins, they found the probiotic group increased 25(OH)D by 25% (6 ng/ml) over the time of the 13 week intervention period, which was a significant mean change relative to placebo (p= .003), which increased by 22.4% (7 ng/ml). There was no difference in the seasonality of the placebo or probiotic groups. About one-third of subjects receiving the probiotic did not show increased 25(OH)D over the intervention period, indicating the changes were even more dramatic in those patients who responded with elevated 25(OH)D levels.
The authors had no firm explanation of why or how this occurred.
- One possibility is that the probiotic changed the acid base balance in the intestine toward acidic, and acidic environments help vitamin D3 absorption.
- Another possibility is the probiotic increased activity of one of the enzymes that metabolize cholesterol, positively affecting 25(OH)D levels.
- The third possibility is that the microbiome somehow directly affects circulating vitamin D levels.
This was an interesting study and highlights that there is still much research to be done about the microbiome and vitamin D.