The gut is often called the second brain. When you need advice about a big dilemma, people will tell you to "go with your gut." When you're feeling anxious about a date or a new job, you may say you have "butterflies in your stomach." There are many common sayings out there concerning gut feelings and the physical and psychological impact of different foods. It turns out these are more than just proverbs, as science reveals more truths about how gut bacteria can affect several aspects of health.

"Many so-called "mind-body" conditions such as chronic fatigue syndrome, autistic spectrum disorder, anxiety, and depression as well as auto-immune conditions may have their starting point in the gut," said Barry Sears, Ph.D., president of the Inflammation Research Foundation and creator of the Zone diet.

Overview of the Brain and Gut Connection

The gastrointestinal (GI) tract does more than just convert the food you eat into nutrients. It also contains the enteric nervous system, which some scientists call the "little brain." But the enteric nervous system (ENS) is not actually little — it contains more than 100 million nerve cells that line your digestive tract. Stretching from your esophagus to your rectum, the enteric nervous system is longer than your spinal cord.

It may not be surprising to learn that something so big has such an impact on your health. But researchers are just beginning to discover exactly how the ENS can affect many aspects of our overall functioning and well-being. It turns out that the GI tract has many more roles than just digestion.

Hormones and bacteria also play a role in gut health, showing that many factors must be in balance to enable us to achieve optimal wellness.

How the Gut Impacts Your Mental Health

Conventional knowledge suggests that the brain sends signals to the gut. What's revolutionary about the new findings is the suggestion that it might actually work the other way as well. Changes in the gastrointestinal system can send signals to the central nervous system, resulting in anxiety and depression.

The digestive tract contains additional information about the potential causes of depression. The vagus nerve is the primary nerve in the enteric nervous system. The vagus nerve acts as a direct link between the stomach and the brain.

This has great implications for how the digestive system may be related to mental health issues, especially since 95 percent of the body's serotonin is found in the intestinal tract. Serotonin is one of the brain chemicals, or neurotransmitters, that regulates anxiety, happiness, and mood. Serotonin deficiency can lead to depression.

Antidepressants such as Prozac and Zoloft, which are known as selective serotonin reuptake inhibitors (SSRIs), boost serotonin levels. But medical scientists continue to look for answers, particularly because not all people with depression respond well to such medications. The answers may be found in the "little brain" within the gut.

The Importance of Digestive Health

If you've ever had uncomfortable bowel symptoms when you were nervous or upset, you can thank the enteric nervous system for that, too. Up to 30 to 40 percent of people have bowel functioning problems at some point, most suffering from irritable bowel syndrome (IBS). Many cases of IBS are also found in those who struggle with anxiety disorders.

Once again, the nerve cells in the digestive tract could be to blame for both anxiety disorders and IBS symptoms. Digestive distress can either be the cause of anxiety or the result of it. A distressed brain can send signals to the GI tract, resulting in IBS symptoms like nausea, bloating, cramping, diarrhea or constipation.

The enteric nervous system, the central nervous system, and the brain all appear to work on a feedback loop. When your digestive tract gets out of balance, it can send signals to the brain and central nervous system, which in turn worsens digestive-related symptoms. Gut health is linked to stress response, affecting the immune system and potentially placing people at greater risk for chronic illness if the gut bacteria gets out of balance. Make sure to visit a gastroenterologist if you are suffering from any digestive illness.

How to Restore and Maintain Gut Health

The link between your brain and your gut health is more than just an interesting coincidence. Restoring optimal gut health could help treat both anxiety and depression and chronic digestive disturbances like IBS.

Because bacteria plays a significant role in the health of the digestive tract, you can try to bring your gut bacteria into proper balance. Eating unprocessed and whole foods is the best way to restore and maintain proper gut health.

"Following a diet that is rich in fermentable fiber (prebiotics) and polyphenols to promote optimal microbial balance in the gut as well as one rich omega-3 fatty acids to reduce gut inflammation," said Dr. Sears.

Many people also find that probiotic supplements and fermented foods and drinks (such as kimchi and kombucha) can help balance the gut bacteria. Scientists know that the bacterial makeup is very different in people who eat mostly processed foods compared to those whose diets contain foods closer to their natural state.

In recent years, researchers have discovered that electrical stimulation of the vagus nerve can be effective in hard-to-treat depression by balancing brain chemistry. A small device is implanted under the skin, which delivers electrical impulses to the vagus nerve. Although this is not widely used yet, some psychiatrists find vagus nerve stimulation to be helpful, particularly in people who don't respond well to antidepressants.

Cognitive-behavioral therapy and antidepressants can sometimes help people with either mental health issues or chronic digestive issues. People with IBS and similar disorders often find symptom relief from managing their stress levels. Stress is linked to several physical and emotional symptoms, including the following:

  • Nausea
  • Abdominal cramps
  • Weight loss or gain
  • Muscle pain
  • Restlessness
  • Inability to concentrate
  • Procrastination

A counselor can help you learn techniques that will help you manage the thought patterns that trigger these symptoms. When you know the techniques to calm your mind and put them into practice, you may be able to halt the trigger before you experience the related symptoms.

The link between your mental health and digestive health is complex and only beginning to be understood. If you suffer from anxiety or irritable bowel syndrome and your doctor can't seem to pinpoint the cause, consider focusing on stress reduction and a more balanced diet of whole foods. By considering your mind and body in a holistic manner, you may be able to find a new source of relief.