Why vitamin D is crucial:
T cells rely on vitamin D to become active. Or they’ll remain dormant and unaware of an infection if vitamin D is lacking in the blood.
“This means the T cell must have vitamin D or activation of the cell will cease. If the T cells cannot find enough vitamin D in the blood, they won’t even begin to mobilize.”
Almost half the world has low levels of vitamin D. The problem increases as we spend more time indoors. No daily dose studies are definitive. Experts say 25-50 micrograms.