Vitamin D as a Risk Factor for Multiple Sclerosis: Immunoregulatory or Neuroprotective?

Abstract

Vitamin D insufficiency during childhood has been linked to the development of multiple sclerosis (MS), typically an adult-onset inflammatory demyelinating disease of the central nervous system (CNS). Since vitamin D was known to have immunoregulatory properties on both innate and adaptive immunity, it was hypothesized that low vitamin D resulted in aberrant immune responses and the development of MS. However, vitamin D receptors are present on many cell types, including neurons, oligodendrocytes, astrocytes and microglia, and vitamin D has profound effects on development and function of the CNS. This leads to the possibility that low vitamin D may alter the CNS in a manner that makes it vulnerable to inflammation and the development of MS. This review analysis the role of vitamin D in the immune and nervous system, and how vitamin D insufficiency in children may contribute to the development of MS.

Vitamin D supplementation and immune-related markers: an update from nutrigenetic and nutrigenomic studies

“…In another study, a dose of 1000 μg/d oral cholecalciferol syrup significantly increased VDR mRNA expression in asthmatic Egyptian children (n 29) (40) . In addition, regular intake of vitamin D supplements among the asthmatic patients increased the serum 25OHD followed by a decrease of VDR mRNA expression (40,41) which was also observed in cancer (42) and multiple sclerosis patients (43,44) . The plausible reason for the increase in 25OHD followed by a reduced VDR expression could be that 25OHD arbitrates the binding of VDR-retinoid X receptor to the promoter sequence of CYP24A1 gene that degrades 25OHD as a negative feedback mechanism (45) .…”

“…Same dose on relapsing and remitting multiple sclerosis patients (n 31) (34) significantly upregulated TGF-β2 mRNA expression in the PBMC similar to those reported in other studies (54)(55)(56) . Yet, some studies reported no significant effect of vitamin D supplementation in multiple sclerosis patients (44,45,(57)(58)(59) showing mixed results.…”

Author response to comment on: Alopecia in multiple sclerosis patients treated with disease modifying therapies

“…The role of vitamin D insufficiency, mainly in childhood, is heavily studied as a risk factor for developing multiple sclerosis (MS). 2 Several mechanisms have been proposed, including the interaction with other risk factors, such as Epstein Barr Virus (EBV) infection. 2 , 3 In contrast, the role of vitamin D in MS progression and relapses is controversial.…”

“… 2 Several mechanisms have been proposed, including the interaction with other risk factors, such as Epstein Barr Virus (EBV) infection. 2 , 3 In contrast, the role of vitamin D in MS progression and relapses is controversial. Several studies have failed to show favorable effects of vitamin D supplementation on MS progression or relapse reduction while others suggested a possible inverse association with MS disability.…”

“…The association between vitamin D and the immune system is indisputable. Several lines of evidence support the benefits of vitamin D to the health of the immune system, and many lines of evidence support the notion that vitamin D insufficiency is a major risk factor for autoimmune diseases, including MS. 2 , 7 …”