“I’ve got a gut feeling about this.”

“The thought makes me nauseous.”

“I’ve got butterflies in my stomach.”

These common phrases intuitively express what science now recognizes: there is a direct connection between the brain and the gut. Some scientists even refer to the gut as the second, or "hidden" brain.

Traditional Chinese Medicine and Ayurveda have long correlated the physiological health of organs and systems with psychological health, especially systems involved with digestion.

Today, Western science is investigating the idea that our happiness may be the result of our health, especially the health of our gut. In a study at McMaster University, Premysl Bercik, an associate professor of gastroenterology, discovered a significant number of patients with gut issues also suffered from anxiety and depression.

Harvard Health Publications reports that what's going on in the head—positively and negatively—is directly reflected in the health of the gut. A study at UCLA shows that not only is the brain talking to the gut, but the communication goes the other way, too.

Understanding Gut Health

Our digestive system is full of life in the form of bacteria. Bacteria may have gotten a bad rap in recent history (which has led to an overuse of anti-bacterial soap), but the truth is our lives depend on them. 

According to Scientific American, approximately 90 percent of what we think of as “us” is not really us—we have are more bacteria cells inside us than human cells, up to 4 pounds, in fact.

These bacteria are responsible for digesting the food we eat and protecting us from foreign invaders. We have a symbiotic relationship with these organisms, many of which live inside the intestinal tract and help support a healthy immune system, says Dr. Oz. 

We all start with large amounts of this gut flora, a gift from feeding at the breast of our mothers and because as children we put everything in our mouth. But over time, we lose some of the bacteria through the natural aging process and the use of antibiotics. 

Keeping Your Gut Happy

So how can we keep the good bacteria in our gut happy and healthy so we can feel the same? Many say probiotics are the key.

Probiotics: Pro means “in favor of.” Biotic means “pertaining to life." Merriam Webster defines probiotic as, “a preparation (as a dietary supplement) containing live bacteria (as lactobacilli) that is taken orally to restore beneficial bacteria to the body; also a bacterium in such a preparation."

You can get probiotics either through certain foods (including yogurt and other fermented foods) or via supplements. If you buy yogurt or other products for their probiotics (rather than making your own), look for labels that say "live" or "active cultures." These typically contain Lactobacillus bulgaricus and Streptococcus thermophilus, two important probiotics.

Supplements can be a great boost for those who lack fermented foods in their diet. Frank Lipman, MD, recommends a daily intake of five to 30 billion viable bacteria. Many probiotic supplement brands are now available, and, due to improved production practices, not all require refrigeration.

Fermentation: Fermentation is a traditional food preservation technique used in cultures around the world. It is a process where microorganisms break down carbohydrates, making the food easier for us to digest and leaving it full of good bacteria. It is also sometimes referred to as lacto-fermentation, a reference to the Lactobacillus bacteria.

Sandor Katz, author of Wild Fermentation, explains that many of our favorite foods, such as bread, cheese, coffee, wine, and chocolate were traditionally fermented, as well as vegetables (pickles, sauerkraut) and drinks (kefir, kombucha). Fermented foods are hard to come by in regular supermarkets in the United States, so it's worth learning how to make your own.

Prebiotics: Prebiotics are food for probiotics. They contain carbohydrates we can't digest, but that the bacteria in our guts can. Examples of prebiotic foods include asparagus, leeks, onions, burdock, and chicory root, according to The Condensed Encyclopedia of Healing Foods. WebMD adds bananas, oatmeal, legumes, and Jerusalem artichokes to that list. Prebiotics are also present in some probiotic-rich foods, like yogurt.

Whether you decide to make your own probiotic foods or take a supplement, it's important to take care of the bacteria in your gut so they can, in turn, take care of you. 

Start today with this winter sauerkraut recipe.