Sodium Intake Differences and its Relationship to the Gut Microbiome in Female Individuals with Irritable Bowel Syndrome and Healthy Controls

Abstract

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction characterized by abdominal pain and changes in bowel movements. Although IBS pathophysiology is still unclear, research has suggested that IBS may be associated with diet and the gut microbiome. Sodium is a nutrient that may be associated with bloating, gut motility, and gut microbial composition. This study investigated the relationship between sodium intake, symptoms, and the gut microbiome in females with IBS and healthy controls. 113 participants provided 3-day food records as well as 28-day symptom diaries. Participants also provided a stool sample for microbiome analysis where 16S rRNA gene sequencing was used for bacterial genus identification. We compared differences in sodium intake and abundances of Lactobacillus and Bifidobacterium between 67 females with IBS and 46 healthy controls. Results showed no significant differences in sodium intake between females with IBS and healthy controls. There was also no significant correlation between sodium intake and the symptoms of interest: abdominal pain, bloating, and intestinal gas. Sodium density (mg sodium /1000 kcal) did not significantly correlate with Lactobacillus and Bifidobacterium relative abundances, but our analysis showed significant associations in abundance of other genera that were not selected a priori. We also found significant associations between sodium, energy, and macronutrient intake. Because sodium is such an integral component in daily diet, our study indicates the need for further, more focused nutrition studies on how sodium intake is associated with gut microbial composition and IBS.