Great comment, MordenGeist. Plenty of additional supplements are also helpful especially if you're coming down with something -- NAC (cheap), lactoferrin (not cheap), mushroom extracts inc. beta glucans for immune function, and dozens of others -- but for everyday use, I like your list, and not just for preventing the flu. Those actions lower your chance of cancer, cardiovascular disease, dementia, and almost every other disease or harmful condition as well.