Seasonal variation in flu and other viral infections, multiple sclerosis, heart attacks and cancer—higher incidence in winter, lower in summer—are all largely due to seasonal variation of vitamin D activation in the skin. Many diseases also follow a latitudinal gradient: increasing incidence the farther north or south from the equator associated with diminishing intensity of sunlight and vitamin D.
Vitamin D deficiency increases the likelihood of autoimmune misrecognition if triggers of the process and genetic predisposition are present. Among the autoimmune diseases best studied is type 1 diabetes, an autoimmune response that can be initiated by gliadin and related proteins of grains and damages beta cells of the pancreas. Children with type 1 diabetes have substantially lower 25-hydroxy vitamin D blood levels at diagnosis compared to children without type 1 diabetes (Franchi 2013). Accordingly, vitamin D supplementation reduces the incidence of type 1 diabetes by 30% (Dong 2013). An impressive 78% reduction in type 1 diabetes was observed with supplementation of 2000 units of vitamin D per day (Hyppönen 2001). A wide spectrum of autoimmune conditions have been associated with vitamin D deficiency, including primary biliary cirrhosis, alopecia areata, multiple sclerosis, Behçet’s disease, vitiligo, autoimmune hepatitis, Sjögren’s syndrome, systemic lupus erythematosis, Hashimoto’s thyroiditis, pemphigus vulgaris, immune thrombocytopenic purpura, Crohn’s disease, and ulcerative colitis (Yang 2013; AgmonLevin 2013).
Vitamin D deficiency is therefore a powerful “permissive” factor in allowing autoimmunity to develop: autoimmune triggers may be present, genetic susceptibility may be present, and vitamin D deficiency permits the process to manifest (Antico 2012). Vitamin D is readily restored using oil-based gelcap forms of cholecalciferol, or vitamin D3.
25-hydroxy vitamin D blood levels should be monitored, e.g., every 6 months, as dose needs vary and can change over time. In the Undoctored U program, we have used 60-70 ng/ml (150-180- nmol/L) as our target for 25-hydroxy vitamin D levels with excellent results and no toxic effects. This blood level is generally achieved with 4000-8000 units per day (most commonly 6000 units per day) of D3 in gelcap form when intestinal absorption is normal, higher if absorption is impaired. (The one relative contraindication to correction of vitamin D deficiency is sarcoidosis; correction in this condition requires additional insights, such as quantity of 1,25-dihydroxy vitamin D. However, this situation is exceptional and unique to sarcoidosis.)