It’s no secret that plant foods (fruits, vegetables, legumes, grains) not only increase stool volume, but can also increase gas production in the intestines. However, the question of what role intestinal bacteria play in this has remained practically unexplored.
In a new study, Spanish scientists compared the gut effects of a Mediterranean diet (dominated by plant foods) and a Western diet (less plant-based foods, more meat, fats, and digestible carbohydrates). The study participants – 18 young healthy men – followed one of these diets for two weeks with a two-week break.
Scientists found that men went to the bathroom about the same number of times on each diet. However, with the Mediterranean diet, the amount of stool was twice as large as with the Western diet: an average of 200 grams versus 100 grams per day. The feces were collected by the study participants themselves and weighed on an electronic balance.
Plant-based foods promote the growth of certain types of bacteria in the gut, New Scientist Rosemary Stanton of the University of New South Wales told New Scientist. These bacteria break down the fiber in plants to provide themselves with food. In addition to undigested fiber and water, these bacteria make up part of the stool mass.
Participants in the study recorded how many times a day they released intestinal gas using a pocket counter. On average, they did seven times more when they followed the Mediterranean diet than during the Western diet.
The scientists measured the amount of gas released after a test meal (stewed beans) using inflatable balloons attached to the anus of the participants. Against the background of the Mediterranean diet, this volume was almost twice as large.
Stanton said that with a plant-based diet, intestinal gas is increased by hydrogen, methane and carbon dioxide, which are odorless. The smell appears due to hydrogen sulfide, which is formed as a result of the breakdown of proteins.
The study authors analyzed the feces of the study participants. It turned out that a plant-based diet stimulates the development of bacteria Agathobaculumand anaerostipes and Agathobaculum butyriciproducens. They are good bacteria because they produce short-chain fatty acids that support gut and body health. Once in the blood, they have a protective effect on the heart, prevent the development of diabetes mellitus, and help normalize cholesterol levels.
The authors of the study concluded that the increase in gas emission from a plant-based diet is a marker of its benefits. “Our Western idea that letting out intestinal gas is a sign of something bad is completely wrong. This is a sign of good nutrition and a healthy gut, ”commented Stanton’s research.