Written by Angeline A. De Leon, Staff Writer. Overweight and obese study participants with a higher abundance of Akkermansia muciniphila significantly improved their glucose metabolism, blood lipids, and body composition following a 6-week calorie restricted diet.

blood lipidsA growing body of research suggests that metabolic disease represents a complex interaction between environmental factors and gut microbiota 1. A healthy gut ecosystem involves high microbial gene richness (microbiota diversity) with specific bacterial species playing a key role in the maintenance of gut health and glucose homeostasis 2,3. Alterations in the composition of gut microbiota have been consistently linked to increased risk for obesity and cardiovascular disease 4. The mucin-degrading bacterium, Akkermansia muciniphila, in particular, has been studied in animal research for its ability to lower body fat mass, reduce adipose tissue inflammation, and improve the integrity of gut flora 5-7. The impact of the bacterial strain on humans remains inconclusive, although some studies suggest that A. muciniphila may be associated with healthy glucose tolerance in adults 8. Dietary changes, such as calorie restriction (CR), may also significantly influence the gut microbiota, possibly increasing the abundance of certain bacterial species while reducing others. To gain a better overall understanding of the role of A. muciniphila in human metabolism and disease risk, researchers at the Institute of Cardiometabolism and Nutrition evaluated the relationship between A. muciniphila abundance and markers of metabolic health, including anthropometric measurements and microbial gene richness, in obese individuals.

A total of 49 overweight and obese adults were enrolled in intervention consisting of 6-week CR diet enriched with fiber and protein, followed by a 6-week weight stabilization (WS) period. At baseline and at Week 12, participants were evaluated on body composition (body mass index, BMI; waist-to-hip circumference; waist-to-hip ratio), serum lipid profile (triglycerides, total cholesterol, TC; low density lipoprotein, LDL; high density lipoprotein, HDL), and insulin sensitivity markers (Homeostasis Model Assessment of Insulin Resistance Index, HOMA-IR). Using advanced biochemical analyses, the abundance of A. muciniphila and microbial gene richness were quantified based on fecal samples.

Results of the study showed that at baseline, individuals with higher levels of A. muciniphila had a lower waist-to-hip ratio (p = 0.04), leptin levels (hormone associated with appetite control) (p 0.005), = fasting blood glucose (p = 0.02) and insulin (p = 0.03), as well as better insulin sensitivity based on HOMA-IR (p = 0.03), relative to those with lower levels of the bacterium. The high A. muciniphila group also remained metabolically healthier throughout the intervention, demonstrating greater improvement in TC and LDL cholesterol after the CR phase and a decrease in waist circumference during the WS phase (p < 0.05 for all). Notably, those with both higher A. muciniphila abundance and microbial gene richness showed the healthiest metabolic profile, specifically in fasting plasma glucose, plasma triglycerides, and body fat distribution.

General findings support the association between A. muciniphila and overall healthier metabolic status and improved clinical outcomes in obese individuals. The importance of gut microbiota diversity in the maintenance of metabolic health is also confirmed by results, highlighting the need for further research into the therapeutic utility of various bacterial strains for human health.

Source: Dao MC, Everard A, Aron-Wisnewsky J, et al. Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology. Gut. 2016; 65: 426-436. DOI:10.1136/gutjnl-2014-308778.

© Article authors (or their employers) 2015. Produced by BMJ Publishing Group Ltd (& BSG) under license.

Posted December 4, 2017.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

References:

  1. Vrieze A, Van Nood E, Holleman F, et al. Transfer of intestinal microbiota from lean donors increases insulin sensitivity in individuals with metabolic syndrome. Gastroenterology. 2012;143(4):913-916. e917.
  2. Swidsinski A, Dörffel Y, Loening-Baucke V, et al. Acute appendicitis is characterised by local invasion with Fusobacterium nucleatum/necrophorum. Gut. 2011;60(1):34-40.
  3. Joyce SA, Gahan CG. The gut microbiota and the metabolic health of the host. Current opinion in gastroenterology. 2014;30(2):120-127.
  4. Png CW, Lindén SK, Gilshenan KS, et al. Mucolytic bacteria with increased prevalence in IBD mucosa augment in vitro utilization of mucin by other bacteria. The American journal of gastroenterology. 2010;105(11):2420-2428.
  5. Everard A, Belzer C, Geurts L, et al. Cross-talk between Akkermansia muciniphila and intestinal epithelium controls diet-induced obesity. Proceedings of the National Academy of Sciences. 2013;110(22):9066-9071.
  6. Shin N-R, Lee J-C, Lee H-Y, et al. An increase in the Akkermansia spp. population induced by metformin treatment improves glucose homeostasis in diet-induced obese mice. Gut. 2013:gutjnl-2012-303839.
  7. Anhê FF, Roy D, Pilon G, et al. A polyphenol-rich cranberry extract protects from diet-induced obesity, insulin resistance and intestinal inflammation in association with increased Akkermansia spp. population in the gut microbiota of mice. Gut. 2015;64(6):872-883.
  8. Zhang X, Shen D, Fang Z, et al. Human gut microbiota changes reveal the progression of glucose intolerance. PloS one. 2013;8(8):e71108.