How are the small intestines like your brain?

Dr. Michael Roizen, MD
Internal Medicine
From a purely physiological standpoint, your small intestines function as your second brain. They contain more neurons than any organ but your brain (and as many as your spinal cord), and the physical structure of the small bowel most resembles that of the brain. In addition, next to your brain, your small intestines experience the greatest range of emotions—in this case, your feelings manifest themselves in the form of gastrointestinal distress.

In your brain, you react to actions—you feel love when your spouse holds your hand, mad when he forgets an anniversary, humiliated when he takes off his shirt at the Bears game and thumps his densely forested chest for a shot at being on SportsCenter. Your intestines do the same thing. They react to the actions of foods that enter their pathway through their anti- or pro-inflammatory effect. Depending on what actions you take in the form of what food you eat, your small intestines can feel mild annoyance (a little bloating), anger (gas), stubbornness (constipation), and even have all-out temper tantrums (a thar-she-blows case of diarrhea).

And because your small bowel is your second brain and 95 percent of your body's serotonin is in your gut (serotonin is what helps control depression in your brain), how you feel influences how you eat, and how you eat influences how you feel. When you eat food that makes you feel bad, you self-medicate with food that may make you feel good in the short term, but will actually contribute to both inflammation and weight gain. Ultimately, when you're caught in a cycle of feeling bad and eating worse, you'll create a chemical stress response in your body—one that's handled by your parking lot of fat.

The best way to tell how stressed you are: Take a look how much belly fat you have. The larger your waist, the higher your stress.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.