Real Issues with Artificial Sweeteners?

by Trinh Le, MPH, RD
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Real Issues with Artificial Sweeteners?

When it comes to artificial sweeteners the nutrition camp is divided. Many consider them “foe,” blaming artificial sweeteners for a host of health problems. To others they’ve been “friend,” helping to kick sugar addiction one diet cola at a time. But the “friend” camp may be getting smaller, because new research suggests artificial sweeteners increase the risk of glucose intolerance, a condition of chronically high blood glucose (a.k.a. blood sugar) that usually leads to diabetes.

These findings go against the grain of what artificial sweeteners were believed to be good for to begin with—helping people lose weight and/or control blood sugar levels. Still, it’s important to note that this is just one study in a sea of research that finds the benefits and harms of artificial sweeteners to be inconclusive.

What did the new study find? The study, published in Nature, shows consuming artificial sweeteners can alter the types of bacteria in the “gut microbiome” (a collection of bacteria naturally occurring in your intestines). This alteration affects metabolism, specifically the way the body regulates blood glucose.

The nitty-gritty experiment details Researchers from Weizmann Institute of Science devised an animal experiment. They separated lab mice into three groups and assigned them one of three drinks:

  1. Water flavored with artificial sweeteners (aspartame, acesulfame, or sucralose)
  2. Water flavored with real sugar (glucose or sucrose)
  3. Plain Water

Which mice had higher blood sugar levels after one week? Surprising to many, the group given artificially-sweetened water had higher blood glucose than the other two groups.

To determine how different sweeteners affected the mice’s gut bacteria, researchers gave all of the mice antibiotics. The antibiotics were meant to kill off all bacteria in the gut and when this happened…POOF! The metabolic changes of the mice given artificially-sweetened water disappeared.

To further test the effect of artificial sweeteners on the gut microbiome of the mice, researchers transplanted bacteria-laced feces from mice in the artificially-sweetened water group into sterile mice, which had no gut bacteria of their own. When the bacteria took hold in the sterile mice, they also showed signs of glucose intolerance.

What does this mean for humans? The researchers didn’t just look at mice. Their paper referred to another study they had done, which tracked 381 non-diabetic human individuals, and found artificial sweeteners consumption to be positively associated with glucose intolerance in people. To investigate further, the researchers recruited 7 volunteers who normally didn’t consume artificial sweeteners and had them drink the artificially-sweetened stuff. They found 4 of the 7 developed signs of glucose intolerance—the other 3 were fine.

What does this mean for you? If you drinks diet sodas or eat foods that contain artificial sweeteners regularly, this research  should give you pause. (It’s a good idea to limit your consumption of added sweeteners—artificial or not.) But because the main study was based on mice (and we all know humans and mice are very different), and the human trial only sampled 7 people, the results are still considered inconclusive. Until more research is done, it’s probably fine for you to enjoy an occasional diet soda.

Photo: Gregg McBride

About the Author

Trinh Le, MPH, RD
Trinh is a registered dietitian by day, blogger at Fearless Food RD by night. She loves helping folks develop a better relationship with food, which includes lots of cooking, eating and learning about nutrition. When she’s not snapping mouthwatering shots of (mostly) healthy food, you can find Trinh HIIT-ing it at her local gym. For more, connect with her on FacebookInstagram and Pinterest.


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