Having an upset stomach in reaction to becoming anxious has to do with the interplay between the central nervous system in the brain and the enteric nervous system in the gut.

“It’s all in your head.” — The dreaded response from your physician when after many tests no underlying cause can be found for a physical complaint.

Most of us have had that experience of butterflies in the stomach. Sometimes those butterflies feel more like an internal tornado, leading to greater discomfort like pain and nausea. Bill Russell, the famous center for the Boston Celtics, regularly threw up before games in a reaction to “nerves” related to his intense competitiveness and desire to win.

Many of us suffer from stomach problems like GERD (gastroesophageal reflux disease), colitis, irritated bowel syndrome and the like.

The underpinnings to the discomforts described above lie in the relationship between two nervous systems: one located in the brain (the central nervous system) and one located in the gut (the enteric nervous system). The two systems share many of the same characteristics, mainly the utilization of neurotransmitters that basically assist in the flow of neural activity.

The awareness that neural activity is occurring in both systems led in part to Dr. Michael D. Gershon labeling the enteric nervous system “the second brain.” His book “The Second Brain” is an excellent read for the layperson and professional alike and can give tremendous insights into your own discomforts.

It is estimated that 85 percent to 95 percent of serotonin (an important neurotransmitter related to mood) produced by the body is actually housed in the gut. It is why many individuals who take selective serotonin reuptake inhibitors (SSRIs like Prozac) for depression may experience stomach discomfort.

These recent research findings regarding the utilization of serotonin in the gut have provided an alternative view to the notion mental problems are underpinnings to stomach problems.

The notion “it is all in your head” is just not accurate.

The stomach and the brain communicate with each other; however, 90 percent of the communication flows from stomach to head. That suggests that the gut has perhaps more influence on your experience than the head.

Where the head has its way is as the storyteller. The brain in the head houses the mind, which has the ability of conscious thought. It drives creative and spiritual processing and interprets our experience. It can be said that the brain in the head interprets a lot of the second brain’s activity and creates words to describe it.

Understanding our experience can get even more complex when we throw in a discussion of the autonomic nervous system that involves our fight-or-flight response.

The importance of a greater understanding into how the different systems in our body interact cannot be overstated. It likely will lead to enhanced interventions utilizing new technology, new pharmaceuticals and perhaps new psychotherapy/counseling techniques.

Until these new developments occur on the basis of more research, it is important to recognize that there is no simple explanation for many of our physical, mental and emotional struggles. Moreover, it is important to view our struggles with a broader brush, perhaps seeing our struggles as related to our entire human experience — not just the mental or just the physical.

A stomach upset or a bout of depression may be more accurately viewed as a sign of imbalance in the interaction between and within all systems. When we view our struggles as involving more than one system, it gives greater veracity to the notion that interventions must be holistic and address our whole being and our whole experience.

Dealing with depression with an antidepressant only or talk therapy only, or GERD with an acid-reducing medication only, though they may be helpful for some symptom relief, are not curative and may actually lead to other problems.

Taking a holistic approach may help in creating balance within and between the different systems.

Adding or increasing physical activity; eating healthier; eliminating toxins; introducing meditation and mindfulness practice; developing or enhancing your spiritual life; nurturing relationships; putting greater emphasis on creativity and increasing knowledge; and learning and utilizing stress reduction techniques are all ways that can help your whole being move towards balance and harmony.