Stressed? Bloated? The two may just be connected

The relationship between mental stress and the digestive system seems confusing at first glance. While it seems like there shouldn't be a connection between the two, it's quite likely that in particularly stressful situations you'll experience sensations in your stomach and intestines.

The disruption of digestive activity is intended to direct resources to what is currently most important to your body, to cope in the best way possible with the stressful event you're facing. As mentioned, emotional problems can lead to heartburn, diarrhea and constipation, yet they also may lead to the narrowing and expanding of the intestines, actions that are considered extremely essential for absorbing the nutrients from the food you put into your body.

Stress also causes you to produce fewer gastric juices, which affects the absorption of substances from food. This is especially true when you eat foods with protein, which require a more significant breakdown in the stomach. And if that's not enough, gastric juices also help protect from bacteria and viruses, which means that a low proportion of them in your stomach may increase your chance of getting sick.

Here are the five main signs that you're stressed, and what your gut is saying.

Heartburn

Recurring or unexpected heartburn can both indicate that you're stressed and can also cause more anxiety in the long run. 

"Heartburn has been linked to stress," Claire Barnes, a nutritionist and technical advisor for the supplements company Bio-Kult, told to the British Mirror. "Evidence shows that 25% of the general population suffers from heartburn at least once a month."

Heartburn was thought in many cases to be related to excessive stomach acid, but new theories suggest the opposite - that low stomach acid could actually be the cause.

Stomach acid protects against pathogenic bacteria entering the intestines, so if you have low stomach acid,  it allows these bacteria to enter and may lead to an overgrowth of harmful bacteria. This in turn can stop the the body from absorbing nutrients such as vitamin B12, folic acid, iron, calcium and zinc.

"Deficiencies in these nutrients can lead to changes in the pattern of chemical neurotransmitter production in the brain, which can increase stress and anxiety," Barnes said.

Bloating

Almost a third of us are affected by abdominal bloating, but many people also report that they experience bloating not only from food but also when they feel stressed or anxious.

Barnes stated that this isn't surprising since when the nervous system is activated in times of stress, blood flow is diverted away from the digestive system. This can cause more food to go undigested and move through the intestines at a slower pace, which can cause inflammation and become a food source for less desirable gut bacteria, which can create excess gas.

She added that it's important to feel calm before eating and don't be distracted with your phone or work so you can concentrate on your meal. Also, chew food thoroughly.

Intestinal motility

Barnes said that it's known that psychological stress causes bowel dysfunction, yet admits that there are many factors that affect bowel motility - how quickly the body gets rid of waste.

Evidence suggests that stress can lead to a change in the gut microbiota (the bacteria in the gut) resulting in increased inflammation. This can lead to bowel dysfunction, such as chronic diarrhea or constipation.

Constipation can be triggered by the overgrowth of harmful bacteria in the intestines, which slow down the removal of feces. On the flip side, bad gut bacteria can have the opposite effect and cause diarrhea due to high levels of serotonin.

Weight gain

Recently, more and more evidence has shown that stress and an increase in the stress hormone cortisol, play a role in obesity. This means that your efforts to lose weight or even just maintain your current weight may be hampered by stress.

It's known that cortisol causes the redistribution of fat cells to the abdominal area while increasing your appetite, and in particular, your craving for comfort food. So when you're stressed you might eat more, especially comfort foods which are less healthy, and your body will also target more fat cells in your belly.

Stress can also affect sleep patterns, often leading to poor sleep. Lack of sleep can further contribute to weight gain as studies show that people who report fewer total hours of sleep are more likely to be overweight or obese.

Irritable bowel syndrome

IBS is a complex disease that isn't easy to diagnose because its symptoms vary from person to person. However, researchers believe stress can be a potential cause of the condition, or at the very least be a major trigger for triggering symptoms.

Barnes stated that evidence suggests that IBS might develop as a result of a disturbance in the gut microbiota, suggesting that the condition may start in the gut. While symptoms are different for each person, two common symptoms are bloating with abdominal pain or cramping, which are often relieved when passing stool.