The Gut-Brain Connection: How Stress Affects Digestion (And What To Do About It)

Many people focus too much on their careers while remaining oblivious to how their lifestyles are shaping their health and performance (1). There are times when despite following a strict healthy diet and regime they fall prey to undesirable aches and pains.

Fatigue, low energy levels, and allergic conditions are just a few on the long list of unexplainable symptoms. More often than not, it’s problems related to the digestive system that storm the harmonious oscillations and functioning of the body.

But stress has become a part and parcel of life today. This is one of the key elements that lay deep down beneath most ailments, especially gastrointestinal issues.

Now let’s take a look at high cortisol levels and their effect on the digestive system

1. Elevated Cortisol Levels Suppress the Immune System

Cortisol offers many benefits. It even has anti-inflammatory properties and is a vital part of our survival mechanisms. However, having high cortisol levels over an extended period of time can suppress our immunity.

Lifestyle factors like poor sleep patterns, lack of a proper diet, and excessive alcohol intake are among the causes of chronic inflammation. As cortisol levels soar up and remain high they wreak havoc on our immune system (2).

The lowered immune response makes us increasingly susceptible to allergies and various other illnesses. Gastrointestinal issues are among the first to rear their head when our immune functions are compromised.

2. The Vicious Cycle of Cortisol and Gut Inflammation

Cortisol is the most important among the glucocorticoid class of steroid hormones released by the adrenals. When used as a medication, cortisol is known as hydrocortisone.

Cortisol turns off the inflammation, which is why prednisolone, a derivative of cortisol is prescribed to calm the inflammation and burning sensation in the stomach.

However, when the inflammation is chronic [long term], and the cortisol levels stay high over a long period, the body becomes increasingly desensitized to its anti-inflammatory action.

The hypothalamic–pituitary–adrenal axis [HPA axis] which stimulates the adrenals to produce cortisol becomes less responsive and slowly stops stimulating the cortisol release. This, in turn, leads to prolonged inflammation and a permeable intestinal barrier.

This creates a vicious cycle of response that is triggered by stress. Stress causes cortisol levels to spike and later fall, which leads to leaky gut and inflammation (3). On the other hand, leaky gut and inflammation caused by a myriad of factors lead to high cortisol levels.

3. Stress Alters the “Good Bug” Population in your Gut

Any imbalance in the gut flora can wreck an otherwise harmonious constitution. Besides digestive troubles, anxiety, depression, cardiovascular ailments, obesity, diabetes, and arthritis can be also associated with gut bug alteration.

Millions of gut organisms form a major support system for the overall health of a person. They support digestion and help balance the immune function. They make nutrients like biotin and Vitamin K, protect the colon cells, and work as neurotransmitters sending signals to the brain.

Many research studies have found that high cortisol levels reduce healthy microflora such as Lactobacillus and Bifidobacteria (4).

Worse is the fact that stress encourages the overgrowth of several disease-causing bacteria. These gram-negative bacteria produce toxins that affect the intestinal epithelium causing inflammation. They can also permeate into your blood and spread throughout your body causing sickness.

Helicobacter pylori (H. pylori) is a type of bacteria that causes infection in the stomach. It is found in about two-thirds of the world’s population. However sickness due to the presence of H.pylori is seen more among those who are stressed whereas a person with lower cortisol levels may not show any symptoms at all. It is evident that psychological stress enhances the colonization of the stomach by H. pylori (5).

Stress synergizes with various pathogenic factors like NSAIDS [non-steroidal anti-inflammatory drugs], colitis-inducing chemicals, or harmful bacteria to produce gastrointestinal disease.

Aggregation (formation of a cluster) and an increase in bacteria and yeast happen when food stagnates in the stomach due to poor metabolism. The bacteria and yeast work on the intestinal lining causing inflammation which spreads further causing an imbalance in the entire ecosystem of the body.

4. High Cortisol Leads to Insulin Resistance

When cortisol floods the body in response to stress, it taps into the body’s protein stores to provide glucose to the body by a method called gluconeogenesis (in the liver). This additional energy is for fueling the flight or fight the body expects to deal with.

During this time period, cortisol thwarts the effect of insulin, rendering the cells insulin-resistant (6). When cortisol levels are chronically elevated, the body continues to remain in its insulin-resistant state.

The high levels of glucose in the blood put a severe strain on the pancreas as it struggles to keep up with the demand for more insulin. But despite the high amounts of insulin being produced, the glucose levels remain high as the insulin is unable to act as long as the cells remain insulin-resistant.

This leads to metabolic disorders like type 2 diabetes. Digestion and absorption of foods become hindered and the intestinal mucosa becomes inflamed. This may lead to gastrointestinal disorders such as gastritis, gastric ulcer, irritable bowel syndrome, colitis, and so on.

Cortisol plays a vital role in guarding the intestinal mucosa against inflammation. An alteration in the cortisol level means an alteration in the biochemical reactions of the gut, which in turn leads to digestive issues.

5. Weight Gain and Obesity

The root cause of obesity is usually an elevated cortisol level. Studies have linked cortisol to cravings for high-calorie foods (7). Direct links have been established between cortisol levels and the amount of calorie intake, especially in women.

Cortisol can actually cause the relocation of triglycerides from storage to the fat cells in the viscera (the internal organs in the main cavities of the body – like the intestine in the abdomen). Cortisol is responsible for relocating triglycerides to visceral fat cells because of which the abdominal region gains fat.

Cortisol also supports the growth and multiplication of adipocytes which are the cells that specialize in storing fat, mainly triglycerides. An increase in the enzymes in the visceral fat cells further augments the production of cortisol at the tissue level. This leads to a steep rise in cortisol levels.  Cortisol receptors are found more in visceral fat cells than in subcutaneous fat.

As discussed earlier, high cortisol levels lead to insulin resistance and even diabetes type 2. As the cells are not able to utilize the glucose from the blood, they cry out for more energy fuel.

The person feels fatigued and his appetite increases leading to overeating and weight gain. The unused glucose in the blood also gets converted to body fat causing even more weight gain.

The Cushing Syndrome

Whatever the cause of the overproduction, abnormally high levels of cortisol can lead to Cushing syndrome or hypercortisolism (8). Overmedication of corticosteroids is a common cause of this syndrome.

An increase in appetite, rapid weight gain especially around the face, chest, and abdomen region, increase in blood pressure, headaches, increased blood sugar, and indigestion are the common symptoms of Cushing syndrome.

Long-term raised cortisol levels or hypercortisolism can cause:

  • Infertility, erectile dysfunction, and lack of sexual drive
  • Women may have excess body and facial hair growth
  • Irregular menstrual cycle.
  • Weakness and muscular cramps
  • Depression, anxiety, irritability
  • Lack of concentration, mood swings
  • Flushed and oedematous face,
  • osteoporosis and loss of bone strength
  • Skin and muscle bruises more easily

Athletes. martial artists, bodybuilders, etc. should take extra care to ensure they are not tempted to take any corticosteroids before training sessions. It is usually the abuse of such drugs, though prescribed by doctors, that leads to such disasters.

What to do About it? How to Reduce Stress?

Well, that deserves an article to itself, so please click on the following link:

Read More: 10 Simple and Effective Ways to Reduce Stress

Before You Go…

Cortisol, the stress hormone plays a vital role in managing nutritional biochemistry at various levels. The human body and mind are intricately woven and connect at every level.

Indigestion can cause anxiety and stress. Stress can lead to indigestion or even diarrhea. These can lead to a lack of sleep and thereby bring in fatigue and stress. Everything is interconnected.

Good health can be achieved only by taking a holistic approach. Physical health and mental health are two sides of the same coin, which together bring balance to the system.

Since 60-80% of the immune system is in the gut and stress negatively impacts the immune system, it is obvious that gut functions are going to be affected by high cortisol levels. While the good bugs get knocked down, some of the nastiest bugs seem to thrive on exposure to cortisol.

Positive lifestyle approaches, dietary corrections, regular exercise, and good sleep can help keep stress at bay.

Articles on Stress and Digestion

Part 1: Understanding Stress and the Cortisol Release Mechanism

Part 2: The Top 5 Ways Stress Affects Digestive Health

Part 3: 10 Simple and Effective Ways to Reduce Stress

About Anju Mobin 104 Articles
The Nutritionist Wordsmith with a Chocoholic Edge! Anju is not just a writer; she's a brush-wielding, coffee-sipping, chocolate-loving wordsmith! With a Fine Arts degree in one hand and a Home Science degree in the other, she blends creativity and nutrition to craft content that truly nourishes the mind. Whether she's painting a vivid picture with words or brewing up engaging web content, she pours her heart into every project. When she's not busy whipping up articles, you'll find her nurturing orchids to bloom in her garden, baking scrumptious treats, and indulging her chocoholic tendencies with dark delights. She is the founder and managing editor of Fitness Hacks.