Every day I start off with a nice glass of liquid extract of the fruit of the orange tree
So orange juice?  I'm a low-carb person so no juice for me, but I do take vitamin C
I also take Vitamin C even though Evidence does not support use in the general population for the prevention of the common cold
I take it because I don't want to get scurvy - LOL!  I don't get much eating keto (meats and green veggies)
Scurvy is nasty. When I start feeling the early symptoms I take more Vitamin C.