A Bright Future
The more we learn about the gut, the more we’re coming to
understand the role it may potentially play in the
development of various diseases. At the same time, we’re
starting to see how tending to it might help treat those
conditions as well.
Many neurological and even psychiatric conditions are
associated with intestinal inflammation, and are preceded by
symptoms in the gut. Autism spectrum disorder (ASD) has
been closely linked with gut inflammation, which coincides
with inflammation in the brain.^45 Many autistic children
have intestinal problems such as inflammatory bowel
disease and an excessively permeable gut lining. In a test of
intestinal permeability (called the lactulose-mannitol test),
37 percent of ASD children tested positive, compared to less
than 5 percent of control group kids—that’s a sevenfold
increased incidence. This effect size certainly suggests a
possible causal link, with either intestinal permeability
causing autistic behavior, autism causing increased intestinal
permeability, or some third factor, such as an environmental
exposure, causing both.
At the other end of the age spectrum, Parkinson’s
disease, a neurodegenerative condition, has also been
strongly linked to gut health. One of the earliest, and often
overlooked, signs of the disease is constipation. Though
scientists are still working to understand this, a significant
clue was revealed in a recent study involving fifteen
thousand patients with severed vagus nerves. The vagus
nerve sends messages from the GI tract directly to the brain,