f you’re one of the millions of Americans for whom diet sodas and artificially sweetened desserts play leading roles in efforts to shed pounds and help prevent long-term diseases like diabetes, new research might give you pause.
The work, done with mice and humans, suggests that artificial sweeteners could raise your blood sugar levels more than if you indulged in sugar-sweetened sodas and desserts.
Blame it on the bugs in your gut, scientists say. They found that saccharin (a.k.a. Sweet‘N Low), sucralose (a.k.a. Splenda) and aspartame (a.k.a. NutraSweet and Equal) raised blood sugar levels by dramatically changing the makeup of the gut microorganisms, mainly bacteria, that are in the intestines and help with nutrition and the immune system. There are trillions of them — many times more than the cells of the body — and they account for roughly 4 pounds of your body weight.
Scientists in recent years have focused more and more on the link between the gut microorganisms and health.
In the latest research, “what we are seeing in humans and also in mice is this previously unappreciated correlation between artificial sweetener use” and microorganisms in the gut, said Eran Elinav, MD, one of the scientists involved in the new study. Elinav and a collaborator, Eran Segal, PhD, spoke at a press conference held by Nature, the journal that published their team’s findings. Both of the scientists are on the faculty of the Weizmann Institute of Science in Israel.
“Initially, we were surprised by the results, which is why we also repeated them multiple times,” Segal said.
Industry groups said the small number of mice and people studied make the findings hard to apply to larger populations. But one scientist not involved in the research called the small study of humans “profound.”
Segal and Elinav added saccharin, sucralose, or aspartame to the drinking water of mice and found that their blood sugar levels were higher than those of mice who drank sugar water — no matter whether the animals were on a normal diet or a high-fat diet.
The mice given artificially sweetened water “were almost diabetic,” said Martin Obin, PhD, who was not involved in the research but read the paper. Obin is an adjunct scientist in the nutrition and genomics laboratory at Tufts University’s Jean Mayer USDA Human Nutrition Research Center on Aging. He said he calculated that the mice fed artificial sweeteners took in a daily amount equivalent to what humans get in about four cans of diet soda.
Although saccharin, sucralose, and aspartame are three different compounds, “the effects were quite similar to each other,” Segal said. Those three sweeteners make up the bulk of the market. Segal said more research is needed to see whether others, such as stevia, can also change the collection of microorganisms in the gut.
When the sweetener-fed mice were given antibiotics to clear their gut of bacteria, their blood sugar levels dropped back down to normal. To gather more evidence of the relationship between artificial sweeteners, gut bacteria, and blood sugar levels, the researchers transferred feces from mice that drank artificially sweetened water into mice that never had. Sure enough, blood sugar levels rose in the recipients.