Vitamin D, Vitamin A, and Riboflavin are crucial for maintaining physical barriers against infections.

“so i guess if you go structurally if you go to physical barriers like mucous membranes epithelial endothelial barriers then vitamin d vitamin a and riboflavin are your three key stars for your physical barriers tight junctions things like that right so you know viruses and bacteria have to get through mucous membranes and physical barriers first in order to even infect you so if you have a poor vitamin d vitamin a riboflavin you're probably at a much higher risk of the virus actually getting into your cell and infecting you”