In my first blog on stress and cancer , I discussed research in the field of psychoneuroimmunology (PNI) which links the body’s nervous system,endocrine system, and immune system to cancer. Another system affected by stress is the digestive system — and digestive problems can contribute to cancer in many ways.
According to Dr. Joseph Mercola, most people, including many physicians, do not realize that 80 percent of your immune system is located in your digestive tract, making a healthy gut a major focal point if you want to achieve optimal health. The gut, brain and primary immune defenses are all connected. In fact, your gut is quite literally your “second brain,” as it originates from the same type of tissue. This is why your mental health can have such a profound influence on your intestinal health, and vice versa.
“Stress can affect every part of the digestive system,” says Kenneth Koch, MD, professor of medicine, section on gastroenterology and medical director of the Digestive Health Center at Wake Forrest University Baptist Medical Center in Winston-Salem, N.C.
What Happens to Digestion Under Stress?
Digestion is controlled by the enteric nervous system, a system composed of hundreds of millions of nerves that communicate with the central nervous system. When stress activates the “flight or fight” response in your central nervous system, digestion is compromised because your central nervous system shuts down central body blood flow, affects the contractions of your digestive muscles, and decreases secretions needed for digestion.
Stress can also cause inflammation of the gastrointestinal system and make you more susceptible to infection. It can cause your esophagus to go into spasms, and can increase the acid in your stomach causing indigestion. Under stress, the mill in your stomach can shut down so that food in incompletely digested and absorption is compromised. Stress can also cause your colon to react in abnormal ways like diarrhea or constipation. “We are all familiar with the athlete or the student who has to rush to the bathroom before the big game or the big exam,” explains Koch.
How Stress Affects Digestion
According to Chris Iliades, MD, the digestive system is affected by stress in fundamental ways. Eating on the run, eating in your car, eating too fast, or eating when you are upset or busy – all of these are very hard on digestion and upset the entire process. Poor digestion leaves the body and the immune system in the same predicament that poor nutrition does – a lack of nutritional factors that support immune functioning and the function of the entire body. This is because a poor functioning digestive system has lost much of its ability to turn what’s consumed into a form the body can use.
Stress can inhibit digestive enzyme function, and cancer has been called an “enzyme deficiency disease” by Dr. Edward Howell. In fact, hurried eating usually means the important first step in digestion – the mouth – is often nearly bypassed by poorly chewed and quickly swallowed food. The starch-digesting enzyme known as amylase is designed to do most of its work in the mouth.
Too low or too high levels of hydrochloric acid in the stomach caused by stress can also be a factor in digestive balance. When we have a low level of digestive enzymes, especially pancreatic enzymes, we may experience numerous symptoms like gas, bloating, belching, muscle pain, skin disorders, insomnia, constipation, diarrhea, and heartburn. These, in turn, have been listed by some cancer researchers as truly early symptoms of cancer.
An inadequate digestive system is often forced to steal enzymes from the immune system to operate, thereby weakening immune function. Poor digestive capability increases the body’s toxic load, and toxemia is a contributing factor to many cancers.
Stress also contributes to poor bacterial balance or gut flora in the intestines. That imbalance, known as dysbiosis, is directly connected to the immune system’s ability to fight off foreign invaders.
Finally, stress can cause behavioral changes like binge eating, indulgence in sugar or other cancer-promoting comfort foods, or simply loss of discipline to eat the foods that support our body’s anti-cancer defenses.
Digestive Problems and Types of Cancer
According to the National Cancer Institute (NCI), all of the following cancers are related to malfunctions in the digestive and gastrointestinal system: colon cancer(colorectal cancer),esophageal cancer, stomach cancer (gastric cancer), pancreatic cancer, liver cancer, cancer of the small intestine,gallbladder cancer or cancer of the bile duct, and cancer of the appendix.
But because stress can compromise general immunity, digestion and ultimately nutritional status – and because proper nutrition is crucial for cancer protection — stress is also related to non-digestive system cancers like breast cancer, prostate cancer, brain tumors, malignant melanoma, and lung cancer. In future blogs, I’ll discuss other ways that stress can contribute to cancer.
 Howell Dr. Edward. Enzyme Nutrition. Wayne, NJ: Avery, 1985