Whenever one of us gets sick in the Franklin household, there’s always talking about going to the shops to buy some “placebo juice“, which is what we call orange juice, specifically the idea that the Vitamin C in orange juice somehow magically “boosts the immune system” to help fight off colds.
I’ve always been dubious as to the supposed ability for foods as immune system boosters–hence the “placebo” in “placebo juice”–but after reading this article, I’m now dubious as to the benefits of “immune boosting” in the first place.
Tl;dr, there are two types of immune system responses, and the feelings we normally associate with “being sick”–fever, headache, runny nose, etc.–are actually caused by one of them; it’s basically trying to burn out the infection while your other immune system tries to figure out how to actually defeat the problem. Think of it like the military in a monster film who come in and ineffectively shoot up everything in the second act, before the Lone Brilliant Scientist comes up with the actual solution in the denouement.
Basically, even if you could (you can’t), you don’t want to be giving those trigger happy body generals bigger weapons than they already have…