Did you know that more than 100 million nerve cells line your gastrointestinal tract from esophagus to rectum? These cells are collectively known as the enteric nervous system, which regulates the gut and is sometimes referred to as our “second brain.” Why? Because the ENS is in constant communication with your actual brain.
While not capable of thought — at least not as we currently understand it — the ENS controls swallowing, digestion, absorption and excretion, and helps transmit feelings of hunger and fullness. Ever felt butterflies before a performance? Or had stomach issues the night before a big event? That’s your second brain speaking up. Today we understand much more about how nutrition influences this conversation — positively or negatively.
Fiber, Fiber, Fiber
Your gut contains a lot of microbes. When you eat fiber-filled foods, your human enzymes are not actually digesting that — instead you’re feeding the bacteria in your gut. Those microbes break up and ferment fiber to produce components that boost immunity, maintain blood-sugar control, protect your intestinal health, influence appetite regulation and prevent disease.
Some good examples of fiber you want to consume regularly: whole grains, nuts, seeds, fruits and vegetables. These also help produce stress-reducing hormones — a good example of the gut-brain connection in action, since stress is connected to mindset.
Other foods also influence this connection. Oily fish — salmon, tuna, sardines — can help reduce the risk of brain disorders. Cocoa, green tea, olive oil and coffee are digested by gut bacteria and improve cognition. Compounds found in turkey, eggs and cheese help produce the mood-booster serotonin. Fermented probiotics like yogurt, kefir, sauerkraut and some cheeses can improve mood and reduce anxiety and depression.
Widespread Effects
Studies increasingly show that the brain and gut influence one another. When we experience stress, anxiety or depression, that can cause diarrhea or constipation, particularly for people with conditions like irritable bowel syndrome. On the flip side, people with bowel conditions are more likely to experience issues with emotion and mood.
Researchers also are beginning to find evidence linking ultra-processed foods — typically, foods packaged with long lists of ingredients you don’t recognize and can’t pronounce — with poor mental-health and cognitive decline, one more reason to be sure highly processed foods make up only a small part of your diet, if you consume them at all.
There’s also research to suggest your gut bacteria may influence your response to cancer treatments like immunotherapy, the aging process, and resistance or sensitivity to insulin, a hormone that becomes elevated in conditions like type 2 diabetes.
Your weight also may be affected. If hunger and fullness hormones produced in the gut don’t function properly, cues between the nervous systems could be skewed, impacting food intake. New weight loss medications that slow down gastric emptying and increase fullness may also be supporting those hormones in the digestive tract.
What You Can Do
It’s pretty clear that taking care to feed your fiber-loving gut microbes will help them take better care of you. Diets high in sugars, processed grains and saturated fats won’t do that — worse, those foods actually can contribute to an increase in hormones associated with inflammation and disease. It’s not necessary to entirely ban foods you love — instead focus on balance, variety and moderation as you move toward a diet that is good for your gut and satisfying to you.
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