Sweeteners in drinks, such as fruit juice and sports supplements, may be toxic to your microbiome.
Bread, yogurt, fruit juice, and lots of other seemingly healthy foods can sometimes contain artificial sweeteners.
And while they might not have the calories of sugar, they may carry other health risks.
Research has linked cancer, type 2 diabetes, and other health problems to the sweeteners. New research is finding more evidence those sweeteners might be killing off some of the bacteria that live in your gut and keep you healthy.
The damage to your microbiome, it finds, could lead to glucose intolerance and gut trouble such as Crohn’s disease.
The latest study, published last month, comes from researchers in Israel and Singapore.
They tested how strains of E. coli bacteria that live in our intestines fared when exposed to various concentrations of artificial sweeteners.
The researchers used versions of E. coli that had been genetically modified to light up in different ways when they detect toxins. They exposed them to 6 sweeteners and 10 sport supplements containing those sweeteners.
Each sweetener damaged the bacteria in different ways, the researchers said. But all of them caused damage.
The research, however, was done in a lab, in conditions that don’t necessarily reflect what would happen in a human’s gut.
“This is a lab study using an in vitro method, and, unfortunately, lacks translation to humans,” said Dr. William Cefalu, chief scientific, medical, and mission officer at the American Diabetes Association.
The glucose intolerance that can potentially be caused by damage to the gut microbiome increases the risk of developing diabetes.
Such “preclinical” studies, Cefalu told Healthline, can’t take into account real-life factors that would affect human metabolism, such as how substances are absorbed in the gut.
“The study is of interest, but the findings cannot be translated directly to human health or condition,” he said.
The study does echo previous findings that have also suggested that sweeteners damage gut bacteria.
A 2014 study, for instance, found mice who had been given sweeteners experienced changes in their gut bacteria, and the loss of some beneficial bacteria.
Those bacteria make up the 1,000 or so species living in your gut, where they help you ward off disease, regulate weight, maintain heart and brain health, and, of course, digest food.
Losing some members of that gut microbiome has been shown to be associated with increased risk of diabetes, irritable bowel syndrome, and other diseases.
If it turns out artificial sweeteners can damage those needed bacteria, that could raise a red flag about our consumption of a range of products.
But we’re not there yet.
A 2015 study, for instance, found that it’s possible different people’s gut bacteria could respond differently to the sweeteners, meaning they could potentially be more toxic to some people’s microbiome than others.
It noted that there are a number of open questions remaining on this potential connection.
“Findings in the laboratory, unfortunately, do not always translate to the human condition, or to other preclinical animal studies,” said Cefalu.
But he noted that the new study is useful in that it provides a method — the different bioluminescent responses — to focus on specific ways in which the sweeteners may affect bacteria.
The study tested six sweeteners — aspartame, sucralose, saccharin, neotame, advantame, and acesulfame potassium-k.
The makers of foods and drinks that use those no-calorie or low-calorie sweeteners are represented by the Calorie Control Council, which found the study’s conclusions “problematic.”
In addition to issues with the lab study not being comparable to how things might play out in a human gut, some of the concentrations of the sweeteners used in the study exceeded amounts typically found in food, the group said in a statement provided to Healthline.
It also noted, in the case of the sport supplements, that the changes in the gut microbiome could have been due to one of the other “number of complex ingredients” in these products.
The trade group also challenged whether it is known that “these or any changes in microbiome bacteria are indicative of negative health outcomes in humans.”
The research into all those effects and complexities continues.
All the sweeteners are considered safe by the Food and Drug Administration (FDA).
Cefalu noted the American Diabetes Association guidelines also says they are safe to use, “within the defined acceptable daily intake levels.”