Diet drinks that contain non-nutritive sweeteners (NNS) have been around for more than 60 years. Since the dawn of the diet drink introduction to the market, a fizzing debate began; do the sweeteners, including aspartame, saccharine, sucralose and stevia, do more harm than good? Are they just innocent satisfiers of our urge to consume sweets or do they do more to the human body? Answering these questions has not been easy for the scientific community. More than 50 years have passed between the first introduction of sweetener-containing diet drinks to the market and the establishment of a link between sweetener consumption and gut microbiome, and blood glucose changes in mice. A study from 2014, where the authors fed mice with aspartame, saccharine or sucralose, illustrated that NNS consumption induced glucose intolerance in mice through metabolic and functional shifts in their gut microbiome. Strikingly, deleterious effects of NNS were fully transferable to germ-free mice through fecal transplants from NNS-fed mice, and the effects were negated by antibiotic treatment. A recent study conducted in light of the findings of the mice study illuminated the impacts of NNS consumption on human metabolism and microbiome. In the human study, human subjects were fed with aspartame, saccharine, sucralose, stevia, and glucose vesicles and placebos as controls. Then, the variation between blood glucose levels and gut microbiome profiles was compared. The study found that the participants who consumed saccharine or sucralose had a higher blood glucose response than any other cohorts. Furthermore, the consumers of any one of the four NNS had altered gut microbiome profiles and metabolic products. For instance, saccharine consumption increased the production of a type of amino acid, simulating the pattern observed in diabetic people. Finally, the research group confirmed that the gut microbiome variation was the underlying cause of the blood glucose spike after NNS consumption through oral administration of microbiomes collected from those who had the highest and lowest blood glucose response after NNS consumption. The authors underlined that the findings did not vindicate NNS consumption. Instead, the results show a full-blown love and hate relationship – NNS do not contain calories but they may alter the gut microbiome in detrimental ways. To read more, please visit the Scientific American.