Stress and Digestion


Written by: Wendy Campbell Parco

Most foods that we take into our bodies are unusable in their natural form. Our digestive system is a wonderfully adaptable system that is able to process the wide variety of foods that we humans eat into simple nutrients our bodies can use and then rid our bodies of unusable waste. Although our digestive system is highly adaptable, numerous studies have shown that there is no system in the body that is more susceptible to the ravages of chronic stress than our digestive system; moreover, research has shown that health of our digestive system affects all other bodily systems.

How Stress Affects Digestion

When presented with a stressor, whether physical in origin, such as getting attacked by a white tiger, or psychological in origin, such as perceived threat to our lives or well-being, our bodies respond as if threatened and digestion is quickly shut down. Our digestive system is innervated with both sympathetic and parasympathetic nerve fibers.  During stress the sympathetic system is turned on. This sympathetic stimulation of the digestive system inhibits the necessary biological functions required for digestion diverting 10-20% of its energy normally used in the digestive process and shunting oxygen rich blood to where it is needed the most in response to the fight or flight response, to the brain, heart, lungs and musculoskeletal system.  This sympathetic response to stress is useful to get us through short- term stressful situations, but what are the consequences to our digestive system of chronic stress?

The Consequences of Chronic Stress on Digestion

Studies conducted on subjects under prolonged stress showed development of three main types of physical illness: multiple stomach ulcers, enlarged adrenal glands and atrophied immune systems. Three risk factors involved in development of ulcers in humans due to the inhibitory responses to prolonged stress include: thinning of the protective mucous layer in the lining of the stomach due to decreased mucous production, damage to the stomach walls due to lack of oxygenated blood flow, decrease in production of free radical scavengers by the stomach.  These factors predispose ulcer formation during times of normal stomach acid production and oxygenated blood flow. The HCL can eat through the thinner lining of the stomach and the additional oxygen in the blood can produce more damaging free radicals than can be neutralized.

Chronic stress suppresses immunity.  Fifty percent of the lymph tissues in the body are located in the gut and 80% of our protective antibodies are located in the gut. During prolonged stress the lymph tissues, lymph nodes, and thymus because severely shrunken, leaving us more prone to illness and infection including bacterial infection of the gut.   In addition to decreased nutrient absorption in the small intestine due to sympathetic response, chronic stress disrupts the balance of friendly and unfriendly bacterial flora, which further disrupts nutrient absorption and in some cases lead to systemic illnesses. Moreover, when the gut is starved for nourishment for prolonged periods of time, hyperpermeability, or leaky gut can occur. In leaky guy syndrome the pores in the GI tract open too wide and can let pathogens, food particles, and toxins from the gut directly into the blood stream. If the liver cannot handle the additional load of toxins, those circulating in the blood stream can trigger allergic responses inflammation, pain and infection. Leaking gut syndrome has been shown to be a causal factor in a myriad of disorders affecting a number of different systems in the body such as: attention deficit disorder, chronic and rheumatoid arthritis, eczema, food allergies, collagen and joint problems, irritable bowel syndrome, symptoms of autism and schizophrenia and skin disorders.

We also suffer indirect effects of chronic stress. When people feel stressed beyond their capacity, they often turn to coping mechanisms that may offer temporary stress relief such as overeating, eating junk foods and foods high in sugar, or drinking too much alcohol or caffeine. These behaviors  are also very damaging to the GI tract.

Using Stress to Our Advantage

Although it is virtually impossible to eliminate all stress in today’s world,  we can learn to reduce the stress response. If we pay attention to our “gut” reactions noticing which issues cause us the most anxiety and worry and affect our digestive system, we can take action to prevent these issues from reoccurring.  We can also learn to use the same connections in our nervous and immune system that make ours guts feel irritable, crampy, spastic and upset to send messages to our digestive systems that are soothing, relaxing, calming and stress relieving. Just as we consciously learn worry and anxiety we can learn relaxation! A few simple but very effective methods that have been shown to decrease stress and improve digestion include simple breathing techniques, meditation, the relaxation response (Herbert Benson), the body scan which relaxes different parts of the body (Jon Kabat-Zinn), and imagery (use your imagination!).  Some people find the relaxation techniques are the only thing they need to greatly improve digestion. Others find these techniques helpful tools to improve digestion as they investigate other possible issues with their doctors such as hidden food allergies or undiagnosed infections.