New research has shown that ingested vitamin D is immunosuppressive and may make some diseases worse, a problem that does not occur when vitamin D is generated by your body in response to sunlight.
The Vitamin D Nuclear Receptor (VDR) acts in the repression or transcription of hundreds of genes, including genes associated with diseases ranging from cancers to multiple sclerosis. However, ingested vitamin D can actually block VDR activation, the opposite effect from vitamin D generated by sun exposure. This means that ingested vitamin D can suppress the proper operation of your immune system.
According to the study’s author, Trevor Marshall, “We need to discard the notion that vitamin D affects a disease state in a simple way. Vitamin D affects the expression of over 1,000 genes, so we should not expect a simplistic cause and effect between vitamin D supplementation and disease. The comprehensive studies are just not showing that supplementary vitamin D makes people healthier.”