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The gut microbiota of women on junk food and stress look similar.
The gut is the link between stress, mood and obesity.
Images from Pixabay (CC0), modified with Adobe Illustrator CC.
Stress and guts are tightly connected. Stress can change the composition of gut microbiota, which are the microorganisms living in the gut responsible for digestion. Digestion is an important process that determines whether essential nutrients are absorbed, ultimately supporting brain functions (such as thinking and speaking). We know by now that microbiota contribute to obesity (read one of our previous blogs) and to mood disorders linked to obesity, such as depression or anxiety. Recently researchers showed that healthy gut microbiota affected by stress resemble gut microbiota on an unhealthy diet.
Anxious female mice have similar gut microbiota as obese female mice
Researchers exposed a group of mice to different diet plans: half of the group (equal number of male and female mice) was on a high-fat diet, the rest, on a balanced diet. After 16 weeks all mice were exposed to a mild stressor for 16 days. The composition of gut microbiota was investigated via DNA analysis of fecal pellets taken before the beginning of the experiment, after dieting and after the stress exposure to compare how the mice’s gut microbiota were affected by the different diets and stress. The levels of anxiety were recorded based on specific tests constructed to measure anxiety-like behavior. In one of the tests, mice were allowed to run across an open arena while their movements were recorded. The mice that spent more time outside the central position of the arena were considered more anxious. The anxiety scores were collected before and after dieting and stress exposure.
It turned out that anxiety levels and gut microbiota differed for male and female mice. When exposed to a high-fat diet, male mice were more anxious compared to female mice. In addition, obese male mice moved less than female mice did in response to stress. In female mice, stress made the gut of lean mice resemble that of obese mice not exposed to stress. The results of this study suggest that stress and a high-fat diet can alter the gut microbiota in similar ways in females. While these results are shown only in mice, the same principles may apply to humans.
Stress and the gut in humans
It has been long known that men and women react differently to stress. The exact mechanisms of this are not well explained. While there may be many explanations for these gender differences, the results of this study suggest a gender-specific reaction of the gut to stress. Considering that the number of women with anxiety disorders is double that of men, this study can have important implications for women’s health.
Written by Lara, edited by Mahur and Monica