{"success":true,"data":{"id":"21100004-a2f2-422e-a7c3-8eb610b9fdb8","title":"Low-cal sweeteners can change gut bacteria — especially if you’re on a popular antidepressant","summary":"Open Health navigation Lifestyle trending now in Health Low-cal sweeteners can change gut bacteria — especially if you’re on a popular antidepressant That guilt-free treat may not be as innocent as it seems.","content":"Open Health navigation Lifestyle\n\n#### trending now in Health\n\n# Low-cal sweeteners can change gut bacteria — especially if you’re on a popular antidepressant\n\nThat guilt-free treat may not be as innocent as it seems.\n\nA [new study](https://link.springer.com/article/10.1038/s44320-026-00225-6) suggests that alternative sweeteners commonly found in sugar-free and low-calorie foods and beverages may interfere with the growth of bacteria that help keep the gut healthy.\n\nBut the effects aren’t always straightforward. Researchers found more than 100 cases where these ingredients behaved differently when combined with other substances — including one widely used antidepressant.\n\nDemand for low-calorie, sugar-free sweeteners is on the rise nationwide. Andrii Lysenko – stock.adobe.com\n\nThat could be significant, given the gut microbiome’s far-reaching influence throughout the body.\n\nThe complex community of bacteria and other microorganisms living in your intestines plays a key role in digestion, [immunity](https://nypost.com/2025/07/17/health/experts-reveal-5-step-approach-to-a-healthier-gut-and-stronger-immunity/), metabolism and even [mental health](https://nypost.com/2026/04/25/health/coffee-may-reshape-your-gut-bacteria-and-affect-mood-stress-and-brain-health/).\n\nWhen the makeup of that ecosystem changes, the effects can be wide-reaching. [Research](https://pmc.ncbi.nlm.nih.gov/articles/PMC10699709/) has linked an imbalance in the gut microbiome to a higher risk of several chronic conditions, including [obesity](https://nypost.com/2021/09/20/study-suggests-microbiome-could-be-key-to-losing-weight/), heart disease, diabetes, [depression](https://nypost.com/2025/11/20/health/your-junk-food-habit-may-actually-make-you-depressed-study/) and even some cancers.\n\n## Explore More\n\nTo investigate how increasingly popular sugar alternatives might affect these microscopic organisms, scientists at the University of Cambridge grew 25 different bacterial species in a lab. The cultures included microbes considered beneficial, neutral or potentially harmful to the gut.\n\nThe team then exposed the bacteria to 39 natural and artificial sweeteners and tracked how quickly the organisms multiplied.\n\nThey found that about three-quarters of the sweeteners affected the growth of at least one bacterial species. Several slowed down or completely stopped the growth of bacteria linked to a healthy digestive system.\n\n“Sweeteners are often marketed as metabolically neutral, but our study challenges this idea,” Dr. Sonja Blasche, a lead author of the study, said in a [press release](https://www.sciencedaily.com/releases/2026/07/260716023552.htm).\n\nSweeteners may affect the gut microbiome, particularly when combined with other substances. Anatomy Insider – stock.adobe.com\n\nBlasche and her colleagues then took the experiment a step further, pairing the sweeteners with other substances, including caffeine, vanilla extract and eight commonly used drugs.\n\nAfter all, these sugar alternatives are rarely consumed alone.\n\n“We take them with drinks, in snacks or even in medication to mask bitterness,” Blasche said. “These common combinations could have unintended effects on our gut microbiome.”\n\n## See Also\n\nThe researchers ended up finding more than 100 instances in which a sweetener’s impact on the gut changed when another compound was present.\n\nIn 34 cases, the combination became stronger, while in 68 cases, it became weaker.\n\nThe biggest surprise involved isosteviol, the sweet compound naturally found in [stevia leaves](https://nypost.com/2026/04/18/lifestyle/zero-calorie-sweeteners-could-alter-the-genes-of-later-generations-new-study-warns/), and duloxetine, an antidepressant commonly sold under the brand name [Cymbalta](https://www.mayoclinic.org/drugs-supplements/duloxetine-oral-route/description/drg-20067247).\n\nWhen scientists combined the two, they found that the pairing strongly suppressed the growth of _Roseburia intestinalis_ and _Parabacteroides merdae_.\n\nBoth bacteria are considered important members of the gut microbiome and have been linked to digestive health and metabolic regulation.\n\nThe finding stands out because duloxetine is widely used for depression, generalized anxiety and chronic pain management. In 2023, more than [4.2 million US patients](https://clincalc.com/DrugStats/Drugs/Duloxetine) were prescribed the drug.\n\nA sweetener combined with the medication duloxetine may affect the growth of key gut bacteria, a new study suggests. Johnstocker – stock.adobe.com\n\nThe researchers then built a mini version of the gut microbiome in the lab, combining all 25 bacterial species into one community. They tested what happened when that ecosystem was exposed to isosteviol and duloxetine together.\n\nThe team found that the combination reduced microbial diversity — a feature often linked to a healthier, more resilient gut. It also reshaped the microbial community, allowing some bacteria to multiply while others declined.\n\nThe ripple effects went beyond the microbes themselves. Additional experiments suggested the changes increased toxicity toward certain host cells and disrupted the activity of cells involved in inflammation and immune responses.\n\n## See Also\n\n“Our study suggests that artificial sweeteners don’t just pass through the body passively — they can interact with gut microbes, and these effects can be amplified or altered by other substances like medications,” said Professor Kiran Patil, the study’s senior author.\n\nStill, the research doesn’t prove that sweeteners or the combinations tested directly cause harm in people.\n\nInstead, it adds to a growing list of questions about how sweeteners may influence the body — especially as researchers continue investigating possible connections between sweetener consumption and conditions such as [type 2 diabetes](https://nypost.com/2022/08/19/artificial-sweeteners-could-cause-diabetes-shocking-new-research-says/), [obesity](https://nypost.com/2018/04/23/your-low-cal-sweetener-is-making-you-fat-and-sick-study/) and [cancer](https://nypost.com/2023/06/29/diet-coke-sweetener-aspartame-is-possible-carcinogen-leaked-report/).\n\n“These findings can help guide new studies towards understanding how sweeteners might influence health in unexpected ways,” Patil said.\n\nLooking ahead, researchers say the next step is finding out whether these interactions happen in people, what amounts are needed to trigger them and whether changes in gut bacteria actually affect health.\n\nWhat do you think?[Be the first to comment.](https://nypost.com/2026/07/18/health/low-cal-sweeteners-can-change-gut-bacteria/#nypost-openweb-conversation)\n\nFor now, these alternatives aren’t going anywhere.\n\nAs Americans search for ways to cut calories and food companies reformulate products to meet changing demands, the use of sweeteners continues to climb.\n\nToday, they’re a fixture of the modern diet, with about [40% of Americans](https://keck.usc.edu/news/calorie-free-sweeteners-can-disrupt-the-brains-appetite-signals/) regularly consuming sugar substitutes.\n\nFiled under\n\nSPONSORED STORIES","source_name":"New York Post","source_url":"https://nypost.com/2026/07/18/health/low-cal-sweeteners-can-change-gut-bacteria/","url":"https://nypost.com/2026/07/18/health/low-cal-sweeteners-can-change-gut-bacteria/","author":"of the study, said in a [press release](https://www.sciencedaily.com/releases/2026/07/260716023552.htm).","author_name":"of the study, said in a [press release](https://www.sciencedaily.com/releases/2026/07/260716023552.htm).","published_at":"2026-07-18T18:29:38.000Z","publication_date":"2026-07-18T18:29:38.000Z","image_url":"https://nypost.com/2026/07/18/health/low-cal-sweeteners-can-change-gut-bacteria/","category":"world","topic":"world","tags":[],"political_bias":null,"bias_score":null,"confidence_score":null,"credibility_score":null,"factual_quality":null,"reading_time":5,"word_count":845,"view_count":0,"breaking":false,"breaking_news":false,"ai_analysis":null,"fact_check_status":"unverified","archive_status":"hot"}}