Why the Study Linking High Infant BMI and Low Calorie Sweeteners is Misleading

Another day, another study on low-calorie sweeteners. This latest study looked at associations between women who reported drinking beverages containing low-calorie sweeteners while pregnant and the body mass index of their eventual child. With pregnancy being such an important stage of life, this publication was sure to grab media headlines. And it did.

Here at Foodinsight, we’ve written many times about headline-grabbing science in the media. Some have been about low-calorie sweeteners. Others have been about caffeine and pregnancy.correlation does not equal causation

In our scientific reviews, communicating how different types of scientific evidence should impact our daily lives is always critical, particularly when it comes to pregnancy. With this in mind, I turned to Dr. Megan Meyer to help put these study findings into context.

KS: What type of evidence does this study provide?

MM: This study relied on dietary assessments where researchers ask people to remember what they ate over a certain period of time. Some have raised concerns about the accuracy of this type of data collection which has been shown to be inaccurate in accounting for what people actually eat. It’s hard enough for people to remember what they ate yesterday, let alone the past several months. On top of that, this type of data (even if it were 100 percent accurate) is designed to see correlations between things. Correlation should not be confused with proof of any direct effect. Higher levels of evidence come from studies designed to assess cause and effect.

KS: In your review of the study, beyond the type of evidence provided, is there anything that stood out to you?

MM: A lot of things stood out that I had questions about. For one, while the study controlled for specific variables such as maternal obesity and diet quality, there are additional confounding variables that may influence the study’s findings. For example, the maternal gestational weight gain was not accounted for, which has been shown to impact child BMI. Also, the authors did not take a wide enough approach for controlling the child’s intake. The authors only examined whether infants began eating solid foods before or after four months of age, and did not asses the types of food or amounts. 

KS: What do global health authorities say about the safety of low-calorie sweeteners?

MM: Here in the U.S., the Food and Drug Administration has determined that low-calorie sweeteners are safe for all populations, including special groups such as pregnant and lactating women and children. Additionally, leading health groups such as the Academy of Nutrition and Dietetics have stated that using low-calorie sweeteners is safe during pregnancy. It's not just American health experts that consider low-calorie sweeteners safe. Other global bodies that have deemed low-calorie sweeteners safe include the European Food Safety Authority, the Scientific Committee on Food (SCF) of the European Union, and Health Canada.

Bottom Line:

Headlines generated from studies like this can raise alarm. It’s human nature for this to cause concern. But taking a more critical look at the science behind media headlines can help ease fears and put it all in perspective.