can study cell division by looking at yeast, for example. We
can study the way a human neuron works by looking at the
nearly identical giant neuron of a squid. And we can study
the development of the fetal brain by looking at fruit flies.
These processes are so important that they differ very little
from species to species, thus enhancing our confidence in
the translation of the results.
As we delve into the study of the intestinal lining, we
can infer much from animal studies, as the cells lining and
surrounding our guts are very similar in all mammals.^34 Is it
certain that industrial chemicals have the same effect in
humans as they do in mice? It will be years before the
human science is settled, but we must make decisions about
the foods we ingest today.
Gluten is a good example of a protein that some people
may be able to tolerate in small, infrequent doses, but that
irritates the gut lining in the context of the Western diet,
which is low in fiber and high in bread, pasta, and packaged
products. Packaged foods are full of emulsifying agents,
which are used to create tasty mixtures of otherwise
insoluble foods and ensure a smooth texture. These are
commonly found in salad dressing, ice cream, nut milk,
coffee creamer, and other processed foods. In animal
studies, adding even a small amount of emulsifiers to the
diet caused a profound change in the gut microbiota,
eroding the mucosa and reducing the average distance
between gut bacteria and intestinal cells by more than half.