I've been tangling with ghost and scorpion peppers lately and even for someone who likes hot food those things will wreck you. They're in the 1,000,000+ Scoville range and make Frank's Red Hot taste like salad dressing by comparison.
Does the heat matter, or is it just a property of the peppers themselves?
Everything in moderation also, too much vitamin c actually makes it an oxidant in the body. Beta-carotene in vegetables widely acknowledged to lower incidence of lung cancer. Beta-carotene pills given to smokers raised lung cancer rates so much they had to end the study early on ethical grounds.[1]
Nutrition is far from solved. It's naive to isolate a substance from a food and claim it alone causes an effect.
I'm a huge chilli fan, gone through a fair share of super hots and anecdotally don't think they can be good for your digestive system in ultra-large doses, have ruined meals and myself on a few occasions. What I get from the study is perhaps choose a vindaloo over a korma, rather than eat as many reapers as possible in 60 seconds.
[1] http://www.webmd.com/smoking-cessation/news/20041130/death-s...
Causality not necessarily the case here.
If by wreck you, you mean they will cause gastro distress, it is because they kill gut bacteria as well as other bacteria.
Capsaicin causes sweating and feels hot by forcing a cell channel open at abnormally low temperatures. This channel normally only opens when you genuinely are too hot.
So, the other reason I eat hot peppers is as a biohack to force my body to dump fluids. I have a genetic disorder that impairs the function of a different cell channel. People with my condition are prone to belly bloat, which I have pretty badly -- but not nearly as badly as I did before I began consuming hot peppers a few years ago.
My belly continues to shrink. The shrinkage correlates to overall improved functionality. I don't care if the belly bloat is merely a symptom of illness or a cause of illness or a little bit of each, I want it gone. I feel strongly that when it is gone, I will function much closer to normal. I don't give a rat's ass if that is because I need to fix things to get rid of it or if I need to get rid of it to fix things. Ongoing progress in reducing the belly bloat serves as an excellent benchmark for general progress.
I did discuss this with a guy with a phd in chemistry and some past a guy with a phd in biology to understand what was going on with my defective body when I accidentally discovered that hot peppers helped me a surprising amount and googling was failing to get me meaningful, useful information. So contrary to popular opinion, this is not just some former homemaker talking out her ass. I also read medical records as part of my job for over five years, etc.
fresh vs processed or dried also matters.
the key finding is to eat fresh red chili peppers everyday. It should be hot and mildly uncomfortable but not the point where it's burning and bleeding