One of the more popular theories for what’s underlying many health problems is intestinal permeability. I’ve heard Cordain talk about this in a radio interview. Yet the other day I came across a new study that looked at the gut and obesity.
This study found that obese patients with low-grade inflammation had altered gut bacteria but normal intestinal permeability. Now it could be the case that altered gut bacteria often precedes intestinal permeability. However, in this situation the subjects were already obese and already had inflammation without any alteration in intestinal permeability. Therefore, the simplest explanation is that the altered gut bacteria is the driving force here.
I’ve seen this same parallel with autism reseach. Some subjects with autism have abnormal intestinal permeability, but others do not. Yet this new thesis(pdf) shows that subjects with autism do have altered gut bacteria. You also have some anecdotal evidence that probiotics can help with autism.
If intestinal permeability was the universal mechanism behind all these health issues, it would be present in all subjects, not just a portion of them. The only constant I’ve seen in what lies behind health issues is altered gut bacteria. Unfortunately, it looks like each generation is starting with a weaker mix of gut bacteria, which predisposes a person to a variety of health problems.