Sweeteners on trial: High saccharin intake shifts gut microbiome impairing glucose disposal

Is it healthy, unhealthy, or somewhere in between to include non-caloric artificial sweeteners (NAS) like sucralose, saccharin, and aspartame in human diets? This has been a hotly debated topic in nutrition and health circles. NAS are used in lieu of nutritive sugars to reduce the amount of calories we consume while maintaining the palatability of foods we like to eat. Additionally, since NAS are typically non-glucose molecules, they can help people with diabetes manage blood sugar levels.

However, some evidence suggests that non-nutritive sweeteners may actually do more harm than good by causing us to consume or store more energy than we otherwise would. If this was true, NAS could actually lead to a higher risk of chronic disease associated with poor blood sugar regulation, such as obesity and type 2 diabetes. Since NAS have become more prevalent in modern foods, the impact of NAS on human health could be dramatic.

NAS pass through the gastrointestinal (GI) tract undigested. What exactly happens to them in the gut is of increasing research interest, since gut bacterial composition is directly influenced by what we eat, and different microbial communities thrive depending on the food choices that we make.

There are two dominant phyla of bacteria in the bowel, firmicutes and bacteroidetes^[1]. Their ratio may be a marker of human health. A high ratio of firmicutes to bacteroidetes has been correlated with more efficient extraction of energy from food. The firmicutes are able to scavenge energy from carbohydrates that would otherwise be excreted by fermenting them and forming short chain fatty acids which are absorbed into the circulation and used for energy. These short chain fatty acids are often linked to health benefits of fiber and resistant starches^[2], due to their ability to nourish cells of the gut and potentially reduce the risk of gastrointestinal disorders, cancer, and cardiovascular disease. On the flip side, the increased efficiency of energy absorption is associated with fat accumulation^[3] and storage^[4].