Abstract
OBJECTIVES: Many factors influence the gut microbiome which in turn mediates physiological responses following food intake, especially when fermentable fibers such as resistant starch (RS) are consumed. Here we examined the relationship body composition and diet on gut microbiome diversity and composition in females. We also compared the effects of glucose and insulin following boiled (∼6 g RS) and chilled (∼12 g RS) potato intake on the gut microbiome. METHODS: Using a randomized cross-over study design 250 g of both boiled and chilled Russet potatoes were consumed on two separate visits with a one-week wash-out period. Fasting and postprandial (15, 30, 60, and 120 min) blood were collected for area under the curve (AUC((0–120))) glucose and insulin calculation. Prior to visit one stool and three-day food records were collected. At visit one anthropometrics and body composition (% fat mass (%FM) and lean mass (%LM)) using air displacement plethysmograph were assessed. Microbiome profiling via 16Sv3–4 sequencing identified bacterial diversity and composition in the stool. BMI, %FM, %LM, mean energy and nutrients, and AUC((0–120)) glucose and insulin following the consumption of each potato were grouped into tertiles then compared to microbiome profiles using Kruskal-Wallis nonparametric tests. RESULTS: Twenty-four healthy females (mean age 28.8 ± 5.9 yr and BMI of 31.8 ± 7.4 kg/m(2)) completed the study. Females with a lower AUC((0–120)) insulin following chilled potato intake had a higher Shannon diversity index (5.8 vs 4.9; P = .033) and Lentisphaerae abundance (3.3 vs ≤ 0.1; P = .005). Higher Actinobacteria (120 vs < 33) was associated with lower AUC((0–120)) insulin (P = .025) following boiled potato intake. Higher %LM ( > 54%) was associated with Lentisphaerae abundance (P = .036). BMI, %FM, diet, AUC((0–120)) glucose following intake of both potatoes, and AUC insulin((0–120)) following boiled potato intake did not correlate with specific microbiome profiles. CONCLUSIONS: These data indicate that microbiome diversity is correlated with reduced insulin response following the intake of potatoes rich in RS, which may be a result of the bacterial fermentation of RS. Lentisphaerae and Actinobacteria abundance were also related to glycemic control. FUNDING SOURCES: The Alliance for Potato Research and Education and Texas Woman's University Small Grants Program.