My step-brother had this around 40. He's okay now, but it was a terrible process involving surgery, carrying around a bag, and chemo which aged him significantly during treatment (from no gray hair to all gray in a couple years).

You would have never guessed he was an unhealthy guy by looking at him, but I do assume it has something to do with foods we consider normal in the US. I've taken a page out of Bryan Johnson's book and started eating well over 100% of recommended daily fiber intake (easy and enjoyable if you make some chia seed porridge every morning), and I will say my digestion has never been better. Keeping the system clear seems like a sane first line of defense to preventing this kind of thing.