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Summary of Vitamin D Deficiency Issues
Vitamin D is essential for many important biological processes and most people get an adequate supply from exposure to sunlight. Long-term studies are needed to determine if low 25(OH)D in healthy individuals leads to disease. Evidence that vitamin D supplementation cures or prevents chronic disease is inconsistent. Despite increased supplementation chronic inflammatory diseases are on the rise. Attention to the alternate hypothesis - low 25(OH)D is a consequence of the chronic disease process, provoked by persistent intracellular infection - may be crucial to reversing this trend and needs further research.
The prevailing dogma that the level of serum 25(OH)D provides an accurate assessment of vitamin D status needs closer examination. Circulating levels of 25(OH)D may not be an accurate reflection of vitamin D status. In those with an autoimmune disease or chronic inflammatory symptoms, 1,25(OH)2D may be elevated. This can lead to osteoporosis and cause inhibition of innate immunity, which is contraindicated in the presence of infection. The resulting immunosuppression may promote persistent infection which has been implicated in chronic inflammatory diseases.
Human cells live in harmony with many types of microbes but some microbes may become pathogenic under commonly experienced conditions. The innate immune system is designed to kill pathogens via 1,25(OH)2D mediated VDR transcription of anti-microbial peptides but microbes may use strategies which down-regulate the VDR in order to live and reproduce within nucleated host cells. Studies using more advanced cell culture and molecular techniques are confirming the presence of previously undetected intracellular bacteria.
Defense mechanisms that intracellular bacteria use to persist and proliferate need to be investigated. Pathogen-induced VDR dysfunction which causes the release of pro-inflammatory cytokines appears to be at the root of chronic disease and low 25(OH)D. Improving VDR activation may be the key to reducing inflammatory diseases. Treatments that up-regulate the VDR to restore normal immune function, reduce inflammation and eradicate persistent bacterial infections require further research. An immunotherapy (Inflammation Therapy) which has demonstrated efficacy in reversing vitamin D metabolism dysfunction and reducing inflammatory symptoms is currently being used by clinicians and warrants formal study.
Key Points
Vitamin D is a steroid hormone which regulates immune system function.
Photosynthesis of vitamin D3 provides adequate vitamin D stores for most individuals.
Low levels of 25(OH)D are seen in healthy individuals, as well as those with chronic inflammatory conditions.
Studies are inconsistent regarding the health benefits of increasing vitamin D stores, vitamin D supplementation may have negative effects.
25(OH)D may not always reflect the level of 1,25(OH)D; accurate assessment of vitamin D status depends on measuring both metabolites.
Intracellular, cell wall deficient bacteria may cause dysregulated vitamin D metabolism and impaired immune system function.
A novel, non-vitamin D VDR ligand (an angiotensin receptor blocker) appears to reactivate the immune system, restore VDR competence, correct dysregulated vitamin D metabolism and reduce inflammatory symptoms.
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