Yogurt contains probiotics so I'm assuming that is the niche he is talking about, i.e, fermented foods. Also I think a lot of the world does eat yogurt. It is very common in US, Canada, Australia, Europe and Asia. I'm not sure about Africa and South America. Apparently, more than 50% of the US population does (or at least yogurt and smoothies, which I'm assuming they meant yogurt based smoothies but who knows) https://www.statista.com/statistics/279748/us-households-con...