A recent scientific study says people should reconsider their heavy use of artificial sweeteners, which may actually increase blood sugar by altering natural gut bacteria.

The study, published in the science journal Nature, was conducted largely on mice and included an experiment on seven people who did not normally consume artificial sweeteners. The researchers primarily used saccharin in the experiments, however some of the experiments also included aspartame and sucralose. They found that some mice and people had a two-to four-times increase in blood sugars and changes in the types of microbes in their intestines. The findings counter the perception that artificial sweeteners, which are not meant to be absorbed by the digestive tract, don’t affect blood sugar or glucose tolerance – which can be a harbinger of diabetes.

The American Heart Association and the American Diabetes Association reviewed the safety of artificial sweeteners in a 2012 statement and concluded they should be used “judiciously” as a way to reduce sugar intake.

The new study, said Dr. Rachel Johnson, an American Heart Association volunteer and one of the AHA statement’s authors, is intriguing because it went beyond animal studies to humans. But she points to its small sample size. About half of the people in the study did not have a blood sugar response. In addition to the seven-person experiment it included an analysis of an ongoing nutritional study on 381 people.

“As with all science, we need to validate this with other samples and larger samples,” said Johnson, who is a professor of nutrition and medicine at the University of Vermont. “It’s something we have to pay attention to, but I don’t think at this point it contradicts our current statement. … We had caveats and our conclusion was fairly guarded. They [non-nutritive sweeteners] were certainly not a magic bullet.”

The study’s authors, Eran Elinav and Eran Segal of the Weizmann Institute of Science in Israel, said more information and confirmation of their results are needed.

As a result of these new findings, though, Johnson said she might reconsider her use of artificial sweeteners beyond her usual morning latte. But she says no one should use this one study to switch back to drinking fully sweetened beverages.

“Be moderate,” she said. “This is not an excuse to say that non-nutritive sweeteners are not good for you, so go back to more sugar. That’s not a good decision. We have a compelling body of evidence on what sugar-sweetened beverages do.”

The AHA recommends that added processed sugars should be limited to about 6 teaspoons a day for women and 9 teaspoons a day for men. Today, the average daily American intake of processed sugar is 22 teaspoons and about 45 gallons of sugary drinks a year. For adults, the AHA recommends no more than 36 ounces, or 450 calories, a week in sugar-added beverages.

Consumers are faced with balancing all of this in light of another recent announcement. The leading producers of sugar-added beverages pledged recently to reduce the number of calories by 20 percent in the next 20 years. Under the agreement with the Alliance for a Healthier Generation, which was founded by the AHA and the Clinton Foundation, the beverage companies said they would market and distribute drinks in a way to help guide consumers to smaller portions and low- or zero-calorie drinks.

The companies also committed to providing calorie counts on vending machines, self-serve dispensers and retail coolers in stores and restaurants. The companies’ progress will be monitored by an independent, third-party evaluator at multiple intervals until the conclusion of the agreement in 2025.

“I think the most compelling thing about it is they are admitting there is a problem with the number of calories in the American diet that is coming from sugary beverages,” Johnson said. “This is the first time they’ve come out and said there’s a problem. I was taken by that.”

For more information:

• NIH and artificial sweeteners