Vitamin D oversupplementation-to-Colitis connection

Since posting my last bit about vitamin oversupplementation in general, I came across this 2009 study from India:

J Clin Immunol. 2009 Jul;29(4):470-8. doi: 10.1007/s10875-009-9277-9. Epub 2009 Feb 14.

Plasma 1,25 dihydroxy vitamin D3 level and expression of vitamin d receptor and cathelicidin in pulmonary tuberculosis.

Selvaraj P1, Prabhu Anand S, Harishankar M, Alagarasu K.

Author information

Abstract

INTRODUCTION:

Vitamin D(3), which exerts its effect through vitamin D receptor (VDR), is known for its potent immunomodulatory activities. Associations between low serum vitamin D(3) levels and increased risk of tuberculosis have been reported.

STUDY SUBJECTS AND METHODS:

Plasma 1,25 dihydroxy vitamin D(3) levels (1,25(OH)(2) D(3)) and ex vivo levels of VDR protein from peripheral blood mononuclear cells were studied in 65 pulmonary tuberculosis (PTB) patients and 60 normal healthy subjects (NHS) using enzyme-linked immunosorbent assay-based methods. Using real-time polymerase chain reaction (PCR), induction of VDR, cathelicidin, and CYP27B1 mRNA were studied in live Mycobacterium tuberculosis-stimulated macrophage cultures treated with or without 1,25 dihydroxy vitamin D(3). VDR and CYP27B1 (-1077 A/T) gene polymorphisms were studied using PCR-based methods.

RESULTS:

1,25(OH)(2) D(3) were significantly increased (p = 0.0004), while ex vivo levels of VDR protein were significantly decreased in PTB patients (p = 0.017) as compared to NHS. 1,25(OH)(2) D(3) levels were not different between variant genotypes of CYP27B1. A trend towards decreased levels of VDR protein was observed among NHS with BsmI BB and TaqI tt genotypes compared to NHS with other genotypes. Relative quantification of mRNA using real-time PCR revealed increased VDR mRNA expression in live M. tuberculosis-stimulated culture in PTB patients (p < 0.01) than normal healthy subjects. Cathelicidin mRNA expression was significantly increased in vitamin D(3)-treated cultures compared to unstimulated and M. tuberculosis-stimulated culture in both patients (p < 0.001) and NHS (p < 0.05).

CONCLUSIONS:

The present study suggests that PTB patients may have increased 1,25(OH)(2) D(3) levels, and this might lead to downregulation of VDR expression. Decreased VDR levels could result in defective VDR signaling. Moreover, addition of 1,25(OH)(2) D(3) might lead to increased expression of cathelicidin which could enhance the immunity against tuberculosis.

In combination with the information I posted about below--Vitamin D receptors are essential to avoiding colitis (inflammation and soreness in the intestines)--I think there's a very solid basis to suspect a connection between Vitamin D supplementation and the uptick in people suffering with intestinal problems in the USA.

It takes only 4 cups of milk to get all the Vitamin D you need. For adults. A tablespoon of cod liver oil has more than three times the RDA of Vitamin D. Again, that's for adults. Unless you have reason to think you need supplemental vitamin D, I recommend you don't take it. And be even more cautious when dosing a child.