How to get a kid used to spicy foods?

I'm from a culture that has a lot of spicy cuisine. The majority of my favorite dishes are spicy. I have 3 kids and we have served them spicy food since infancy. Two love spices but one started to complain of food being to spicy a couple years ago. Attempts to make it less spicy have been unsuccessful. He still claims that it is too spicy. I do most of the cooking in the family. We have started to let him make his own dinner if he doesn't want what we are having and he has a sandwich basically every night. We aren't happy about it since he's so frail but at least he's eating.This is more of a problem at my mom's house or when we travel back to my home country every year. He won't eat at my mom's house when she cooks him dinner and can't eat the same things we eat when on vacation. Even if want to go out to a local ethnic restaurant it's a problem.I know you can train your body to accept spices more. My wife isn't from my ethnic background and didn't like spicy food at first but she's okay with it now. I'm not sure how to do that with a kid though. Is exposure therapy the only way?I realize this may not be a big deal to a lot of people. That's totally cool but I would greatly appreciate it if responders could stick to the question being asked. If you trained yourself or your kid to love spicy foods, how did you do it? If you think this is unimportant or abusive, please hold your comments as I am not asking for opinions. Thanks. via /r/Parenting https://ift.tt/2NjlJU9