Gut Bug Slims Waistlines, Improves Blood Sugar
With commentary by lead researcher Karine Clément, MD, PhD, director of the Institute of Cardiometabolism and Nutrition at Pitie-Salpetriere Hospital in Paris
A common gut microbe with a tongue-twisting name — Akkermansia muciniphila —helped overweight and obese people lose more belly fat and gain better blood-sugar control in a recent study from the Institute of Cardiometabolism and Nutrition at Pitie-Salpetriere Hospital in Paris.
The study compared naturally-occurring levels of A. muciniphila, or AKK, in 49 human volunteers before and after a six-week weight-loss diet. People with the most (some in the “High AKK” group had levels 100 times higher than those in the “Low AKK” group) had smaller waistlines and lower blood sugar, insulin and cholesterol levels before dieting. While both groups lost similar amounts of weight on the diet, the High AKK group lost more abdominal fat and improved their blood sugar levels and insulin sensitivity more than the Low AKK group, notes lead researcher Karine Clément, MD, PhD, director of the institute. The study was published online June 22 by the journal Gut.
But don’t look for A. muciniphila supplements on drugstore shelves any time soon. Clement says the “just right” level in the human body isn’t known. And researchers also don’t know for certain how to increase levels in humans. “It is possible that there is an optimal abundance level to maintain metabolic health,” Clement notes. “However we don't know what promotes this optimal abundance.
This oval-shaped bacterium was discovered just 11 years ago. And researchers are just beginning to understand its role as “caretaker” of the surprisingly important and complex layer of mucus that lines the intestines.
A sticky gel, the mucus layer is emerging as an important player in metabolic problems including obesity, abdominal fat, inflammation and diabetes. Thicker is better. The mucus layer forms a protective blanket that keeps gut microbes from touching intestinal walls, preventing harmful byproducts from stimulating an immune response that can boost levels of bodywide inflammation. A healthy “gut barrier” also seems to help control blood sugar and blood fat levels. Research suggests the mucus layer may be thinner in people with diabetes.
The Role of "Good Bugs" In Disease Protection
A mucus layer full of A. muciniphila also seems to be important. This bacterium makes up just 3 to 5 percent of all gut microbes, but it’s the main microbe floating in the mucus layer, and it’s busy. A 2013 lab study by some of the same researchers, published in the journal PNAS, found that in rodents, A. muciniphila prompted cells lining the intestines to pump out more endocannabinoids. These help control inflammation, and that in turn triggers cells to release peptides called GLP-1 and GLP-2 that help control blood sugar levels. That may be why rodents who got extra A. muciniphila had less insulin resistance and better blood sugar levels.
The presence of A. muciniphila also prompted cells to release more mucin, the main ingredients of the mucus layer.
A. muciniphila also breaks down food into the small chain fatty acids that other beneficial bacteria thrive on, the researchers note in the new study. People with the most “AKK” had a more diverse community of good bugs in their digestive system including several types of Firmicutes and Bacteroidetes as well as Actinobacteria and Euryarchaeota, Clements points out. “A. muciniphila is part of an ecosystem,” she said in an email interview. “As 'partners' they could contribute collectively to improved metabolism. We have shown that the best improved metabolic profile is seen in patients with high levels of A. muciniphila and a rich and diverse microbiota.”
Can we feed and pamper our personal A. muciniphila colonies? Patrice D. Cani, PhD, a professor at Belgium’s Université catholique de Louvain who was involved in both the 2013 study and in the new study says researchers don’t know exactly how that can be done, but they have some clues. In the 2013 study, high-fat diets suppressed these microbes while high-fiber diets helped support them in rodents, he notes. His research group plans to test a supplement in humans soon. “We are currently preparing a human intervention in obese and insulin resistant patients that will receive Akkermansia muciniphila orally for three months. We expect starting the clinical trial by the end of this year 2015.”