Did You Know You Have A Second Brain? I Didn’t…

…or maybe I should say WE didn’t know (yuk-yuk :)).

But apparently it is real and it resides in and communicates from your gut. “There are more neurons in the GI tract than anywhere else except the brain”, says psychiatrist Dr. James Greenblatt. Dr. Greenblatt has been successfully treating patients with severe mental disorders, such as ADHD, OCD and eating disorders by prescribing probiotics supplements… and the results have been “miraculous”.

While researching a previous blog post concerning gut bacteria and obesity I developed an intense interest in the apparent connection between gut bacteria and almost every aspect of human health and immunity. I began by looking into the heady (and seemingly controversial) concept that certain bacteria are responsible for cancer (more on this later…) but somehow stumbled into the realm of the “gut-brain axis”.

It began with a tweet by Mark Sisson of Mark’s Daily Apple calling attention to a recently published case study: “In a kid suffering from sleep seizures and cortical malformation, a paleo ketogenic diet led to complete resolution.” I learned from the paper that ketogenic diets have been used for at least 90 years to treat epilepsy and the researchers proved that an animal fat-meat based diet (“paleolithic ketogenic diet”) was just as effective in this severe case. The fact that the diet was applied as an effective treatment for a mental disorder itself is fascinating (to me) and I am aware of the numerous other health effects of a “Paleo” or “Primal” diet but call me dense, it wasn’t clicking with me what the mechanism is that would have such a dramatic effect on a person’s mind. Is it reduced brain inflammation from not eating grains? Is it better absorption of certain nutrients, such as critical fats (after all the brain is 90% fat)? Well, maybe…

I kept looking and I think my other brain’s new obsession with gut bugs guided me to some EXTREMELY fascinating reading. Besides the elimination of grains and legumes, the elimination of gluten seems to be especially good for healthy gut flora. (Gluten causes a negative good bacteria to bad bacteria ratio, which leads to inflamation and leaky gut syndrome). Dr. Perlmutter, neurologist and author of Grain Brain and Brain Maker, says there is a strong correlation between an imbalance in gut bacteria and various neurologic conditions, such as depression, ALS, Alzheimers and Autism. I came across another article that surveyed 37 microbiologists asking (among other things) on a scale of 1 to 10 (1 = Strongly Disagree and 10 = Strongly Agree) if they believe a ‘Paleo’ or ‘Primal’ diet is a strategy for a healthy microbiome. The result for this question was 9.1.


I cited several great sources below but there are many more out there, especially from recent work in the field of psychiatric medicine. Researchers are saying they have just touched the surface of this vast ocean of bacterial mystery but what they have discovered so far is:

  • Certain gut bacteria are connected to specific personality types. When they swap the gut bacteria of two different personality types, they swap personality traits as well. (Experiments with transplanting gut bacteria from outgoing mice to the guts of timid mice results in outgoing mice and vice versa.)
  • Bacteria communicate from the gut to the brain (the one in your skull) via the vagus nerve. (Experiments where they sever the vagus nerve confirm that doing so stops the effect of gut bacteria on personality, mood, etc.)
  • A team of biologists at MIT found that a specific probiotic strain, Lactobacillus reuteri, improved mood, restored a youthful appearance to the skin, and promoted general health by increasing levels of oxytocin, the love hormone.
  • The probiotic L. rhamnosus markedly affects GABA levels in certain brain regions and lowers the stress-induced hormone corticosterone, resulting in reduced anxiety- and depression-related behavior.
  • A number of microbes can produce other neurotransmitters, such as norepinephrine, serotonin, and dopamine. For example, Bifidobacterium infantis, taken as an probotic, alters serotonin levels – just like Prozac but without the undesirable side effects.
  • At least 50 percent of the body’s dopamine and more than 90 percent of the body’s serotonin, our feel good neurotransmitters, come from within the gut.

Here is an excellent video explaining the human microbiome and its importance (cartoons always help me understand complex concepts):


It gives new meaning to the phrase “gut feeling” huh?

Sources: