DIETARY SUGAR ALTERS THE GUT MICROBIOME, triggering events that can lead to metabolic disease, pre-diabetes, and weight gain. These findings of a new mouse study remind us of our microbiome’s important role in health. Today we explore the relationship between dietary sugar and fat, the gut, and obesity. Today we examine sugar and the microbiome.
Recognizing the indispensability of the gut microbiome for health, Columbia University (USA) researchers examined the initial effects of a Western-type diet on mice microbiomes.
The human microbiota comprises up to 100 trillion symbiotic microbes, mostly bacteria in the gut.
Exercise, the Gut Microbiome, and Health
Diet, the gut microbiome, and health
Researchers put the mice on a Western-style diet high in sugar and fat. Here are the results after four weeks on this diet:
The animals demonstrated characteristics of metabolic syndrome, including weight gain, glucose intolerance, and insulin resistance. Moreover, their microbiome changed dramatically.
The microbiome alterations included sharp drops in the amount of a particular type of bacteria (segmented filamentous) common in rodent, chicken, and fish microbiota. Other bacteria forms increased in volume.
The reduction in the filamentous bacteria appeared critical to health, with the effect mediated through Th17 immune cells. More specifically, the filamentous bacteria reduced the number of Th17 gut cells. Subsequent studies showed that Th17 cells are necessary if the animal is to dodge metabolic disease, diabetes, and weight gain.
Here’s how the Th17 protects the mice: These immune cells make substances that slow the absorption of “bad” lipids from the intestines. The cells also decrease intestinal inflammation. Study author Ivaylo Ivanov, Ph.D., puts it more simply:
“The Th17 cells keep the gut health and protect the body from absorbing pathogenic lipids.”
Sugar versus fat
Is it the sugar or the fat that is the culprit for the adverse changes in the gut? If you guessed the sugar, you are correct.
Again, Dr. Ivanov:
“Sugar eliminates the filamentous bacteria, and the protective Th17 cells disappear as a consequence. When we fed mice a sugar-free, high-fat diet, they retain the intestinal Th17 cells and were completely protected from developing obesity and pre-diabetes, even though they ate the same number of calories.”
But taking out the sugar did not benefit all mice. Sugar removal did not benefit those who entered the study with no filamentous bacteria; the mice became obese and developed diabetes.
Sugar, the gut microbiome, and health — My take
The mice study reminds us that diet can influence the microbiome. Interestingly, dietary interventions, such as minimizing sugars, may only work for those with certain bacterial populations in their microbiome. A certain diet approach may work for some but not others.
Could probiotics help? Supplementing the mice’s filamentous bacteria led to Th17 cell recovery and protection against metabolic syndrome. This beneficial effect occurred despite the animal’s high-fat diet. I imagine a day when some consider adding something like filamentous bacteria to our gut microbiome.
Thank you for joining me in this look at dietary sugar and fat, the gut, and obesity. Finally, here are some other pieces I wrote about the microbiome:
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider if you seek medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
