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In a new study, participants who consumed sugar substitutes showed an altered microbiome and spikes in blood glucose.

Aspartame, and "diet drinks" hit the stores in the 1950s. Ever since, rumors have swirled that such sweeteners—which today also include saccharin, sucralose and stevia—do more than satisfy a sweet tooth without the calories of sugar. But whether that “more” exists hasn’t been easy to establish.

In a new study of four sugar substitutes, researchers found that these nonnutritive sweeteners don’t just travel through the body unnoticed. The study results, published on August 19 in Cell, link two of the sweeteners—saccharin and sucralose—to spikes in glucose levels and suggest all four are tied to a shift in gut microbe profiles.

In 2014 researchers found a link between microbiome changes and blood glucose responses in mice after intake of sugar substitutes. To see if those same links applied to humans in the new study, the scientists selected participants from a potential pool of more than 1,375 people, ruling out anyone who consumed noncaloric sweeteners in their regular daily life. Some had unknowingly done so by way of protein powders, chewing gum, or low-sugar snacks or desserts.

The researchers split the final 120 participants into six groups of 20. In four of these groups, participants consumed commercial packets of one of the four sweeteners at levels below their federal daily limit. A fifth group consumed only the filler used in these packets, which is commonly added to bulk out the tiny amount of sugar substitute they contain. The sixth group had no intervention.

During the two weeks that participants consumed their assigned sweetener or the filler, they also took oral glucose tolerance tests, which are used to measure the body’s response to sugar and can be employed to diagnose some forms of diabetes. For these tests, they drank a glucose solution every morning after overnight fasting and used home-based continuous glucose monitors to track their blood glucose levels. The researchers also collected oral and stool samples from the participants to analyze the species of microbes they hosted. Study investigators additionally measured levels of some products of metabolism in the blood.

The participants who consumed saccharin or sucralose had a steeper blood glucose response than any of the other groups. When participants consumed any of the four sugar substitutes, their gut bacteria profile changed during the two weeks of intake. Along with these changes, levels of the metabolic products changed, too. For example, in participants who took saccharin, the production of a type of amino acid increased, echoing patterns seen in people with diabetes.

To confirm a link between microbial profiles and blood glucose responses, the investigators orally administered microbiomes—taken from the human participants with the highest and lowest blood glucose spikes following sweetener consumption—to germ-free mice. Mice exposed to microbiomes from human “top responders” showed changes in their blood glucose that “very significantly mirrored those of the donor individuals,” says study author Eran Elinav, principal investigator of the Host-Microbiome Interaction Research Group at the Weizmann Institute of Science in Rehovot, Israel, and director of the Microbiome and Cancer Division at the German National Cancer Center in Heidelberg.

"The effects of the sweeteners on blood glucose are likely highly personalized", Elinav says. But the results suggest these compounds don’t just pass through the body, as some originally thought. Part of the personalized response will relate to the health of the person involved.

Ice Cream Is Better for You Than a Multigrain Bagel, New Study Suggests

A new study from Tufts University in Massachusetts suggests that ice cream is a healthier choice than a multigrain bagel and other foods like saltine crackers.

In the research, experts at the Friedman School of Nutrition Science and Policy at Tufts developed a "Food Compass" to rank any type of food from 1 to 100 based on nutrition; the higher the number, the healthier the food.

When comparing foods, the study gave an ice cream cone with nuts and chocolate ice cream a 37, while a multigrain bagel with raisins received a 19 and saltine crackers a 7.

While chocolate-covered almonds and sweet-potato chips might not be surprising healthy choices, other options that ranked high are plain Fritos chips, which were given a 55, and whole grain frozen french toast, which was scored at 35. Nonfat cappuccino was ranked at 69.

"Once you get beyond 'eat your veggies, avoid soda,' the public is pretty confused about how to identify healthier choices in the grocery store, cafeteria, and restaurant," said Dariush Mozaffarian, the study's lead and corresponding author, dean for policy of the Friedman School. "Consumers, policy makers, and even industry are looking for simple tools to guide everyone toward healthier choices."

When it comes to the categories measured, snacks and sweets garnered the lowest ranking with an average of 16.4. It's also no surprise vegetables and fruits — along with legumes, nuts and seeds — are the highest. Starchy vegetables received an average of 43.2.

Sugar-sweetened sodas came in with an average score of 27.6, while 100 percent fruit and vegetable drinks came in at 67.

According to the study, the healthiest meat is seafood, which was given an average of 67, followed by poultry and beef, whose average scores were 42.67 and 24.9, respectively.



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