Many years ago, I was a lowly freshman graduate student, acting as a guinea pig for another graduate student in her last year. Sitting before my eyes, was a massive quantity of mayonnaise-laden tuna fish salad. For the experiment, I had to consume as much salad as I could, overfilling my stomach as fast as possible. I ate right up to the point of vomiting and couldn’t eat another spoonful. My classmate was elated. That is exactly the situation she needed to test out her hypothesis. Immediately, my friend took a sample of my blood. I looked pale and felt very nauseous.
Tuna, You Never Looked The Same After Graduate School
The experiment was looking for a hormone secreted from my intestines called cholecytokinin. They knew at that time, that the hormone was produced by the brain. In this study, my fellow graduate associate wanted to see if it was also produced in the intestines. She found it in my blood and proved that it was from the GI tract (intestines). This chemical messenger was sensing fullness, sending a signal up to the brain, getting me to stop eating.
Oh Boy, Clamp That Hinge!
Here, the intestinal tract is acting as a satellite brain. It stimulates a nerve highway that runs from the intestines to the brain called the vagus nerve. This sends the message to the brain and the entire nervous system to stop putting stuff in your mouth. If you ignore your body and continue eating, cholecytokinin will increase stimulation on that nerve/brain highway causing feelings of nausea and ultimately resulting in vomiting.
Cholecytokinin senses protein and fat in food. It then stimulates the gall bladder and the pancreas to secrete bile and pancreatic enzymes to start emulsifying and breaking down your meal. Our intestinal tract is very smart. It passes up information to the brain to fully update and notify the host that he/she may be about to blow lunch. It’s a strong sign to either stop eating or slow down.
Now what if I told you that probiotics, like the brain-like effects of cholecytokinin, may actually help us control how we feel? What if I said that researchers are discovering that the bacteria that make yogurt and other beneficial organisms may actually decrease anxiety and put us in a better mood?
Stay tuned for Humans, You Do Have More Than One Brain! Part Two, tomorrow, I will discuss why natural foodstuffs may ultimately replace anti-anxiety agents like diazepam (Valium) and antidepressants like sertraline (Zoloft).