Not only could stress have such a deleterious effect on the intestinal microbiota as junk food, but its effect would be even more damaging in women.
Obesity is associated with a high prevalence of mood disorders. Additionally, stress and a high-fat diet can alter the gut microbiota and contribute to obesity.
A new study published in Scientific Reports investigated the interrelationship between diet, stress, gut microbiota and mood disorders. For this, the researchers used a group of 8-week-old mice.
Junk food disrupts the gut microbiota
Half of the female mice and the male mice were fed a high-fat diet. The other part received normal food. After 16 weeks, the mice were exposed to mild stress for 18 days. Before and after this phase, the animals performed tests to assess their behavior, anxiety and motor skills. In addition, faecal samples were taken to analyze their microbiota.
The results revealed gender differences:
– While the relative increase in body weight was the same in females and males, male mice appeared more vulnerable to the anxiogenic effects of the high-fat diet.
– Obese male mice showed decreased motor activity in response to stress, which was not the case in obese female mice.
– In females, stressed lean mice acquired an intestinal microbiota comparable to that of obese mice, not subjected to stress.
These results suggest the importance of considering gender as a biological variable impacting the intestinal microbiota, and being at the origin of the development of obesity-related mood disorders.
Stress severely alters the gut microbiota in women
Converging data asserted that a dysbiotic microbiota contributes to obesity and its associated metabolic phenotypes (heart disease, insulin resistance, hepatic steatosis, systemic inflammation). This new study shows that stress, like junk food, can also alter the composition of the gut microbiota in a mouse model.
In humans, the prevalence of anxiety disorders in women is almost double that in men. Major depression is also more common in women. The researchers suggest that a possible source of these gender differences may be answered in the gut microbiota.
Bridgewater LC Gender-based differences in host behavior and gut microbiota composition in response to high fat diet and stress in a mouse model. Sci Rep.7; 7 (1): 10776.