You know, I think there really is something to it.
I used to get sick on a fairly regular basis before switching to a plant based diet, but now I never do. I mean really, I never do. I can't remember a single cold in the few years I've been vegan now.
As for allergies, I recall that years back, some days outside would leave me running for the antihistamines... but it just occurred to me that that hasn't happened for about just as long.
Whether it's the plant based diet or just a coincidence, it sure is nice.