How does being used to spicy foods work?

Question

More specifically:
Why, when a person from a region that typically eats spicy food eats something you think is hot, do they say “this isn’t spicy” even if there’s like 5 jalapenos (exaggeration.) Can they taste the spice but they’re just used to it and are being mean to my caucasian tastebuds, or can they literally not register any spice. If the second one, how does this work? If the prior, how does being used to spicy things work?

Edit: on reflection, 5 jalapenos clearly isnt an exaggeration.

Edit 2: I’m talking MY caucasian tastebuds. Me being from Europe where spice is not everywhere. I’m not saying white people can’t be used to spice. (That’s sort of what I was asking anyway, is spice tolerance nature or nurture)

In: Biology

Answer 1

I think the desensitization occurs in the brain, at least to some extent. I know a person whose mouth became numb on one side due to a brain injury. At first, the numb half of the mouth could tolerate pretty much any level of spiciness because it couldn’t feel anything. Meanwhile, the other half was normal, able to tolerate something hotter than jalapeños but not quite as hot as habañeros.

Over time, the numb half of the mouth slowly regained sensations. Early in the process, mild spices like black pepper or mild hot sauce were enough to be uncomfortable to this half of the mouth despite it still being generally numb. But in the same bite of food, the normal half of the mouth couldn’t detect much spiciness at all.

After a couple of years, the numb side of the mouth became increasingly capable of detecting other sensations like texture, temperature, etc. However, as more and more spicy food was eaten, that side of the mouth was slowly able to handle more spiciness. AFAIK it still hasn’t reached the heat levels of the other half of the mouth.

It was the same tongue, mouth, and nerve endings, but there was different brain matter interpreting the signals. The brain’s capacity to handle heat seemed to evolve just like a baby or child’s does.

PS – Of course, this is just an anecdote, but interesting nonetheless.