Your Guide to Digestive Health

Your digestive tract—a.k.a. “the second brain”—is a smart system that is acutely sensitive to your feelings. Here’s how to keep it healthy (and happy).

Photo by Jamie Chung

Your gut is essential for more than just instincts. It has to make sure that your body gets fed, which is a very complex job: The stomach churns food; the small intestine breaks the mixture (called chyme) into smaller molecules so that the body can absorb nutrients; and the large intestine converts what’s not needed into—well, you know. When the process works as it should, you’re happily oblivious. But when one part goes awry, so can your quality of life. For the good of your gut, here’s the full digest on what’s normal and what’s not.

The Psychology of Your Stomach

Why do we have so little control over what goes on in the digestive tract? Because the gut has a mind of its own.

Your Other Brain

The gut’s nervous system, sometimes called “the second brain,” is a network of more than 100 million neurons (cells that transmit information through electrical and chemical connections) that runs the length of the gastrointestinal tract. Of course, this “brain” doesn’t generate emotions or hold on to memories. But it can operate the digestive system independently of the brain in your head, deciding when to move food from the stomach to the small intestine, when to release hormones, when to expel waste, and even when to send food back from whence it came. (That’s why you can’t resist the urge to vomit when you’re sick.) “The brain doesn’t like to micromanage,” says Michael D. Gershon, M.D., a professor of pathology and cell biology at Columbia University and the author of The Second Brain ($15, “It leaves the details of digestion up to the gut.”

To make these gut decisions, the second brain uses many of the same tools that the regular brain uses—chief among them, the neurotransmitter serotonin. In fact, 95 percent of the body’s serotonin stockpile is in the gut. While the brain’s serotonin helps create feelings of well-being, the serotonin in the gastrointestinal tract is its “sword and shield” against hostile agents, such as bad bacteria. “Serotonin in the gut can mobilize inflammation, detect potential invaders, and essentially get the gut to mount a full-fledged defensive reaction,” says Gershon.

The Mind-Body Link

“If your stomach disputes you, lie down and pacify it with cool thoughts,” said the legendary baseball player Satchel Paige back in 1953. Turns out, he was on to something. The gut is intricately linked to your state of mind, as you know if you’ve ever had butterflies before a big date or felt sick before an exam. The primary connection is the vagus nerve, which starts at the base of the brain, travels down the neck and across the chest, then branches throughout the gut. Most of the messages that travel the vagus nerve go from the gut to the brain, not vice versa. In a healthy person, they are mostly unconscious: benign updates about routine gut activity so that the brain can maintain equilibrium in the body. But in people with digestive issues the messages aren’t so pleasant. Imagine that your gut is in distress—maybe you have painful bloating. “Now instead of sending nice messages that all is well, the gut is going to send the brain distress signals,” says Gershon. “It’s possible that these unconscious warning messages will become so overwhelming that they’ll materialize as anxiety and depression.” You know the expression “Which came first, the chicken or the egg?” It’s the same with digestive issues and anxiety. “We don’t know whether stress is causing the bowel to go wrong or the bowel going wrong is causing mental stress,” says Gershon. That said, there’s no question that “adding a singular stressful event on top of chronic stress makes chronic digestive symptoms worse,” says Yuri Saito, M.D., a gastroenterologist at the Mayo Clinic in Rochester, Minnesota.

The Butterfly Effect

This perpetual stress and distress is different from a plain old case of nerves. When you have a sudden bout of diarrhea before a big interview or presentation, your body is probably going into fight-or-flight mode. As your brain issues a surge of stress hormones, it signals the body to put all the focus on the problem at hand—leaving the regulation of digestion on the back burner. In response, your gut may go into overdrive (otherwise known as diarrhea or vomiting). Feeling butterflies in the stomach is just a milder version of the same reaction.


5 Healthy Gut Strategies

Often it’s the simple things that keep your system stable.

1. Commit to exercise. Exercise gets the colon moving, helping you maintain regularity. It’s also useful when dealing with irritable bowel syndrome, or IBS: A recent Swedish study published in the American Journal of Gastroenterology showed that people who exercised three to five times a week for 12 weeks had significant improvement in IBS symptoms; non-exercisers didn’t see the same benefits.

2. Chew your food. “To be happy, our gastrointestinal tract needs us to take time for our meals and chew our food thoroughly and slowly,” says J J Virgin, a certified nutrition specialist in Palm Desert, California, and the author of The Virgin Diet ($26, Smaller, more frequent meals may also help you to avoid overwhelming the digestive system.

3. De-stress. “Psychological interventions can be very helpful when it comes to treating gastrointestinal symptoms,” says Saito. She suggests training in mindfulness, a simple meditation technique that involves focusing on the present moment and reframing how you respond to stress. Talk therapy, yoga, and even hypnotherapy have also been known to help.

4. Take a probiotic. The gut is home to tens of trillions of bacteria, of which about 10 percent are “bad” (causing digestive distress) and 90 percent “good” (controlling the bad bacteria). Probiotics is just another word for “good bacteria.” Ingested regularly, they’ll help skew the ratio of bacteria in your gut to the good. Some forms of yogurt and kefir contain probiotics, but in nowhere near the amounts that supplements deliver. How to pick one? Shekhar Challa, M.D., a gastroenterologist in Topeka, Kansas, and the author of Probiotics for Dummies ($17,, recommends that you look for bottles with 5 billion or more CFU (colony-forming units) and at least five strains of bacteria (with tongue-twister names like Lactobacillus acidophilus). Each person’s gut is different, so if you’re taking a probiotic for relief from a squirrelly gut and nothing changes after a few weeks, it’s worth trying another one.

5. Keep an eye on it. This may not sound appealing, but one of the easiest ways to check your gut health is to peek into the toilet before you flush. Red can indicate blood in the lower gastrointestinal tract, which could be a sign of colorectal cancer, Crohn’s disease, ulcerative colitis, or hemorrhoids. Black can point to upper-gastrointestinal-tract bleeding, such as stomach ulcers. (Just be aware that iron tablets and foods like beets can have harmless, color-altering effects.) Firm is good, hard could mean dehydration or constipation, and no shape means diarrhea. Skinny (pencil width) could also be a cause for concern. “It might indicate a narrowing in the colon, possibly from a tumor,” says Lawrence J. Brandt, M.D., the chief emeritus of gastroenterology and a professor of medicine and surgery at the Albert Einstein College of Medicine, in New York City.