Effect of Diet Change on Gut Microbiota: Observational Pilot Study of Four Urban Couples

BACKGROUND: Recent studies have focused on changes in gut microbiota following a dietary change. We identified how the distribution of gut microbiota changed when the dietary habits of young city dwellers improved using an intervention in which married couples shared the same dietary habits. METHODS: Four married couples in their 30s with irregular eating habits and sedentary lifestyles were asked whether they had any uncomfortable symptoms. A nutritionist advised them to reduce their intake of processed meats, carbonated beverages, and late-night snacks. After a 6-week intervention, subjects were asked whether they observed any changes in their symptoms. Their stool samples were collected before and after the intervention and analyzed to determine whether the gut microbiota had changed. RESULTS: After the dietary intervention, some subjective symptoms of the participants improved. Specifically, a subject who complained of frequent abdominal pain/diarrhea and one who complained of fatigue showed improvement in those symptoms. In addition, some subjects showed improvements in symptoms such as skin disease or constipation. Intestinal microorganisms between spouses who share the same dietary habits were found to be similar. CONCLUSION: Improvements in eating habits can change the distribution of gut microbiota and alleviate various uncomfortable medical symptoms. Within married couples, the distribution of gut microbiota became similar when the spouses shared the same dietary habits. These results suggest a possible correlation between family-level changes in eating habits and the health of all family members.