
Vitamin D has recently been acknowledged as an essential nutrient for proper immune system function. Before the pandemic, most doctors uneducated in vitamin D thought it
was necessary only for calcium balance and bone metabolism. However, integrative
doctors like myself have long recognized the multifunctional effects of vitamin D,
including:
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normal cell division (cancer prevention, wound healing)
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controlling inflammation
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blood pressure regulation
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insulin and glucose balance
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skin health (eczema and psoriasis)
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muscle health
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cognitive decline
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immune system regulation (autoimmune disease)
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immune response (infections)
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and other conditions.
Interestingly, vitamin D has its ultimate effect on the DNA (stored genetic information) in the cell nucleus. It modulates the expression of many genes that control cell activity.
Vitamin D Fine Tuned for The Immune System
Your immune cells have receptors for vitamin D. This includes the B cells, T cells, antigen-presenting cells, and lung cells. Adequate vitamin D levels support the healthy functioning of these immune cells. In addition, vitamin D stimulates the production of proteins known as cathelicidins that disrupt the outer coating of viruses and bacteria. In addition, vitamin D promotes the activity of proteins known as defensins, which attract immune cells to an area of infection. And lastly, vitamin D has the dual function of activating inflammatory chemicals known as cytokines (which in turn increase immune activity with infection) and reducing the excessive activity of cytokines that create too much inflammation, as seen with the current virus and variants.
Understanding Vitamin D
There are two inactive precursors of vitamin D known as cholecalciferol (from sunlight) and ergocalciferol (foods). The liver and kidneys convert these precursors into the active form. Therefore, people with diseases of these organs are more susceptible to vitamin D deficiency. The skin converts ultraviolet B rays (UVB) into vitamin D3 (cholecalciferol), which is then activated by the liver and kidneys into its active form.
Reasons for Vitamin D Deficiency
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Geographical location: northern latitudes mean people have less sun exposure
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Atmospheric conditions: clouds and air pollution influence the concentration of UVB reaching people
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Clothing: the more one is covered, the less skin is exposed to sunlight
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Sun protection practices such as protective clothing, hats, staying indoors, and sunscreen reduces skin vitamin D3 production
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Skin pigmentation: people with darker skin make less vitamin D3 with exposure to sunlight
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Genetic Variations: variations in one’s genetic makeup can make them more susceptible to low levels of D3 or activated vitamin D
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Obesity: increases risk of vitamin D deficiency by storing D3 in body fat
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Absorption problems: conditions such as Crohn’s disease increases vitamin D deficiency due to absorption problems
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Magnesium deficiency: people with low vitamin D have vitamin D metabolism problems