Myth busting: foreigners can't digest nori

I remember watching a TV program in Japan last year in absolute incredulity. A doctor, an actual certified doctor, made a statement along the lines that 'foreigners can't digest nori because they lack the gut bacteria necessary'. This is untrue, but it is based on a real scientific finding that has been misunderstood.

Researchers discovered that some Japanese people have gut bacteria that help break down certain seaweed components. This led to the oversimplified idea that only Japanese people can digest seaweed. But in reality, gut bacteria adjust over time. Moreover, digestion varies from person to person, not by nationality. There are some Japanese people who often don't have the gut bacteria. In addition, the study was more about kombu and wakame, rather than nori sheets. Kombu and wakame are widely regarded as being a bit tougher on the stomach, initially. 

Nori is generally easy to digest, but people who didn’t grow up eating seaweed may need a little time to adjust. Some people have mild iodine sensitivity and / or difficulty digesting high‑fiber foods, but these aren't 'foreigner' specific issues, just normal variations in digestion. Some people (Japanese or not) may get mild bloating from high-fiber sea vegetables. In reality, most foreigners' digest nori perfectly fine.