When people experience disgust or fear, their stomach acidity is higher. This is shown by research in which participants watched videos while the acidity of their stomach was measured. It is unclear whether the emotions lead to higher acidity, or whether a more acidic stomach causes people to experience more intense emotions.
Research shows that experiencing intense emotions is associated with changes in the acidity of our stomach. Physiologist Josephine Porciello from Sapienza University in Rome and her colleagues gathered for their research, described on the preprint website Biorxiv, 31 men with an average age of 24 years, and asked these subjects to take a ‘smart pill’, a sensor that measures the pH value, temperature and pressure in the intestines. As the pill moved through the gastrointestinal tract, the subjects watched videos that can arouse disgust, fear and happiness. The pill then left the body naturally.
After each video, the participants completed a questionnaire. They indicated how intense the emotions were that they had felt during the video. When the participants watched disgusting or scary videos, their stomach pH turned out to be higher than when they were neutral. Those with the sourest stomachs reported the most disgust and anxiety. The participants who reported feeling happy had a less acidic stomach.
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It is still unclear whether a sour stomach amplifies these emotions, or whether experiencing these emotions leads to higher acidity. The emotions seemed unrelated to temperature or pressure changes in the GI tract.
Stomach ulcer
Negative emotions can lead to acid production in the stomach, stomach scientist says Ignacio Rebollo of the German Institute for Food Research near Potsdam. He points out that previous research has shown that stress from unemployment is associated with deaths from stomach ulcers. These are often caused by too much acidity.
To find out whether our emotions influence the acidity of the stomach, or vice versa, the researchers could administer ‘proton pump inhibitors’, according to Porciello. These are substances that prevent the stomach wall from producing a lot of acid. They could then measure whether this leads to a decrease in the intensity of negative emotions.
Porciello and her team are now conducting a similar study in female participants. With follow-up research, they hope to determine how changes in the gut affect our emotional state.
