Are Food Additives Making Us Fat?

New research shows that common food additives may not be as harmless as we thought. Nutrition Diva explains how the latest research in microbiology is changing the way we think about nutrition and health.

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #324

Several of you asked me to comment on the recent research linking common food additives to obesity, Type 2 Diabetes, and inflammatory bowel syndromes.  

"What should we do about emulsifiers?" wrote Robert, sounding just a wee bit panicked. "I don't know where to begin!"

For those of you who may have missed the headlines, researchers found that two compounds that are widely in food processing caused weight gain, blood sugar problems, and inflammatory bowel disease in mice. 

A couple of qualifiers are in order. The mice were fed very large quantities of the additives - much more than you would ever be exposed to, even on a diet composed entirely of processed foods. And the only mice that developed inflammatory bowel disease were mice that are genetically predisposed to that condition. This study did not find evidence that these additives are causing weight gain or disease in humans. Nonetheless, the headlines definitely sent a lot of people scrambling to their fridges and pantries to scan labels. 

Are These Additives in Your Cupboard?

The two compounds used in the recent study, carboxymethylcellulose and polysorbate-80, are both emulsifiers. There are at least a dozen other emulsifiers used in food processing and I bet the scientists could have produced similar results from any of them - these just happened to be the two they focused on. 

Emulsifiers are used in all kinds of processed foods, such as yogurt, ice cream, and salad dressing, to enhance the texture and keep ingredients from separating in the container. And for decades they've enjoyed "GRAS" status - ingredients that are generally recognized as safe when used in prescribed amounts.

Testing to establish the safety of food additives doesn't focus on weight gain or glucose tolerance. GRAS testing looks at acute toxicity, carcinogenic and reproductive effects. In other words, if the mice don't drop dead, develop cancer, or have abnormal babies after ingesting large doses, the ingredient is considered harmless. 

This isn't the first time that supposedly safe ingredients have come under fire. Health-conscious consumers have long been wary of the synthetic chemicals that sustain the processed food industry. Many parents, for example, worry that food dyes may contribute to ADHD. There was the whole kerfuffle last year over yoga mat chemicals in bread

For me, what's really newsworthy about this study is that the researchers were able to tie these effects to changes in the gut bacteria of the mice. Eating the additives altered the intestinal bacteria in the mice, which in turn caused the weight gain, blood sugar issues and inflammation. How do they know? Because when they fed the additives to special mice that had no bacteria in their intestines, they didn't cause the same problems. 


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.