Exercise confers minor changes in 3 gut microbiome genera in adults with obesity
An 8-week exercise intervention was associated with improvements in insulin sensitivity and visceral adiposity in adults with obesity, with modest changes observed in three gut microbiome genera, according to study findings.
“This study demonstrated that an 8-week exercise intervention in humans with obesity causes significant improvements in cardiovascular and metabolic health in the presence of modest changes in three gut microbiome genera, all belonging to the short-chain fatty acid-producing Firmicutes phylum,” Rebecca J.H.M. Verheggen, MD, MSc, an internist in the department of physiology at Radboud University Medical Center in Nijmegen, the Netherlands, and colleagues wrote in a study published in Obesity.
Researchers enrolled 7 men and 7 women with obesity who did not engage in regular physical activity at baseline to participate in an 8-week cycling exercise program two to four times per week. Each training session consisted of a 5-minute warm-up, 50 minutes of cycling at 65% to 85% of the participant’s heart rate reserve, and a 5-minute cooldown. Participants were asked not to change their daily food intake during the study. Fresh stool samples were collected before and after the intervention. A hyperinsulinemic-euglycemic clamp was used to measure insulin sensitivity, and DXA scans measured body composition.
In stool samples collected after the intervention, no changes in alpha or beta-diversity of the gut microbiota were observed.
“The lack of exercise-induced alterations in alpha and beta diversity is in accordance with previous human exercise intervention studies of both shorter and longer duration and similar exercise intensities,” the researchers wrote. “This is in contrast to cross-sectional work in athletes that demonstrated marked differences in the gut microbiota diversity when compared with inactive controls, suggesting a role for exercise as an influencer of gut microbiota diversity.”
On the genus level, a significant change was observed in Ruminococcus gauvreauii, uncultured genus from Lachnospiraceae and Anaerostipes after intervention compared with baseline. No changes were observed for other gut microbiome genera.
The study cohort had a reduction in visceral adiposity (959 cm3 vs. 897 cm3; P = .02) and an increase in insulin sensitivity (3.8 mg/min/kg vs. 4.5 mg/min/kg; P = .007) from baseline to after intervention. Maximal oxygen consumption increased from 27.7 mL/min/kg at baseline to 31.9 mL/min/kg after intervention (P < .0001).
In correlation analysis, an abundance of Anaerostipes was positively correlated with maximal oxygen consumption (r = 0.64; P = .015). Ruminococcus 2 was correlated with visceral adiposity (r = 0.51; P = .0048). An abundance of R. gauvreauii was positively associated with insulin sensitivity (r = 0.6; P = .023) and maximal oxygen consumption (r2 = 0.61; P = .0018), and negatively associated with visceral adiposity (r = –0.54; P = .028).
“R. gauvreauii is positively correlated with insulin sensitivity and cardiorespiratory fitness, which suggests a potential role for this acetate producer to cause improvement in insulin sensitivity in response to exercise,” the researchers wrote.
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