Why do some people get diarrhea when they eat spicy food, get nervous, or catch a cold? The mystery that has lasted for many years has finally been solved

Expert of this article: Wang Xiaohuan, Doctor of Medicine, Fudan University

The weather is getting cooler day by day, and foodies have more choices. On a beautiful day, you can start with some spicy crayfish to whet your appetite:

What's up with you? There's nothing that can't be solved with a hotpot meal. If one meal doesn't work, then two meals will do:

However, some people are still savoring the spicy food after eating it, and suddenly their stomachs feel churning... and they are about to have diarrhea!

In fact, many people have had this experience: diarrhea after eating spicy food, being nervous, or catching a cold. What is going on?

Next, let’s explain them one by one.

Why do some people get diarrhea after eating spicy food?

Chili peppers contain an ingredient called "capsaicin", which will bind to the "capsaicin receptor" in the body after entering the human body. However, excessive capsaicin cannot be completely decomposed and metabolized by the digestive tract.

Therefore, when the "capsaicin receptor" is activated, the gastrointestinal motility speeds up in order to quickly excrete capsaicin from the body. However, when the gastrointestinal tract suddenly "speeds up", it cannot take into account the "movement rules", resulting in irregular gastrointestinal motility, intestinal movement disorders, and irregular bowel movements.

The time that feces stays in the intestines is shorter than normal, and the water in the feces is absorbed by the intestines less, causing the feces to be too watery and shapeless, resulting in symptoms of "diarrhea".

Moreover, after the "capsaicin receptor" is activated, it activates the pain nerve conduction pathway and transmits a "burning sensation". This is why we sometimes have "snot and tears" when eating spicy food.

In addition, there are a large number of diverse bacteria in our intestines. Under normal circumstances, there are more beneficial bacteria and fewer harmful bacteria in the intestines, and the intestinal flora is in a "balanced state".

When the intestines are irritated (such as intense hot or cold stimulation, spicy and greasy stimulation, or excessive physical fatigue), it will cause an imbalance of intestinal flora, leading to indigestion symptoms such as diarrhea and constipation.

Of course, the reaction after eating spicy food is also closely related to each person's physical constitution. In life, some people are "afraid of spicy food" while others "can't live without spicy food". This is mainly closely related to personal physical constitution, living habits, etc.

For people who often eat spicy food in their daily lives, the diarrhea that occurs occasionally after eating spicy food will gradually ease over time, and the symptoms will be relatively mild.

For people with irritable bowel syndrome, there are more "capsaicin receptors" in the intestines that can bind to capsaicin. Therefore, these people are more likely to suffer from diarrhea after eating spicy food, and the symptoms are more severe.

Why do you get diarrhea when you catch a cold or are nervous?

In fact, it is not only spicy food that can cause diarrhea. Many people also suffer from diarrhea when they catch a cold or are nervous. The root cause is that the stomach and intestines are "irritated". These common "irritants" can be roughly divided into three categories: diet, temperature and spirit.

Food is the most common stimulus for diarrhea. In addition to the spicy food we mentioned above, a large amount of intake of some high-sugar foods can also promote intestinal peristalsis and cause diarrhea, especially the intake of a large amount of fruit containing fructose.

Fructose malabsorption is more likely to cause diarrhea. In addition, large intake of fried foods, high-protein foods or caffeine may also cause diarrhea.

Temperature stimulation is also a common cause of diarrhea. This is because unlike skin nerves, gastrointestinal nerves are more sensitive to pain caused by pulling, cold, heat, etc., compared to cutting pain.

Especially our belly button, the skin is thinner, there is no muscle or fat tissue below the belly button, it is more susceptible to cold and induce irritable bowel syndrome leading to abdominal pain, diarrhea and other uncomfortable symptoms.

Mental factors can also cause diarrhea. Because there are neural structures in the human gastrointestinal tract that are independent of the central nervous system, which are closely connected to the central nervous system and influence each other, we call this "emotional line" connecting the brain and the intestines the "brain-gut axis."

When we have negative emotions such as tension, anxiety, anger, etc., this emotional signal will be transmitted to the gastrointestinal tract through the "brain-gut axis", affecting the peristalsis of the gastrointestinal tract and causing indigestion symptoms.

In addition, there are some other reasons that may cause diarrhea, such as bacterial or viral infection, excessive drinking, drug abuse, etc. Therefore, if mild diarrhea symptoms are not relieved in time, you should seek medical attention in time to find out the cause and prescribe the right medicine.

What should people who are prone to diarrhea pay attention to?

To ensure gastrointestinal health, we have the following suggestions:

Dietary moderation: Try to avoid eating fried or high-fat foods, and reduce the degree or frequency of spicy food. Eat regularly, do not overeat, and try to eat fresh food.

Keep the temperature moderate: Keep warm in daily life, especially the navel and other parts that are susceptible to cold. Avoid eating food that is too hot or too cold. Avoid alternating hot and cold food during meals (e.g. hot pot + iced drinks).

Relax: Find good ways to relieve stress (such as writing a diary, talking to friends, etc.), and intentionally cultivate your ability to stabilize and regulate your emotions.

Strengthen exercise: Develop the habit of regular exercise to improve gastrointestinal blood circulation and enhance body immunity.

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