Definitely depends where in China for this to be true. Shanghai or Beijing? Won't be much, if any, better than in the US. Countryside? Likely will be much better, but food is often scarce in general in these areas.

This was in a major city (Guangzhou). I think China has its own issues with food safety and additives. Very little regulatory action has led to some very nasty stories about adulteration and gastric problems.

I think when I was in China I was basically in a perpetual state of food poisoning for several years.

My assumption is that it could be multifactorial, societal and family integration along with diet and who knows what else. Life is stupidly complex