D
C
Zinc
Quercetin
Ecgc
Aspirin
Famotidine
NAC
Horse paste
Etc.
All these just plain work. A combo pill would be great.
D3
C
Zinc
Eggs (farm raised if possible)
Fatty fish like sardines and salmon
I almost never get sick and have never had a prescription drug in my life (and I'm almost 60).
As for the fatty fish, yes, I've actually eaten a tin of sardines pretty much every day at lunch for the past quarter century. I eat them right out of the tin with a toothpick. You can take them anywhere.
In the morning, I'll fry up 2-3 eggs in butter and have a full-fat yogurt (which means little to no added sugar) with berries mixed in.