How Food Preservatives Make You Fat

It's no secret that we've become a heavy population. Changes to our food supply with our heavy reliance on packaged and processed foods-may have something to do with it. If you were never a stickler about reading food labels, you will be after reading what two common food stabilizers do to your gut and your body. The additives in question are emulsifiers-a type of food additive that helps maintain food texture.

The fate of emulsified mice-is it yours?

Researchers have suspected that emulsifiers damage the gut, allowing bacteria to cross the delicate epithelium the porous lining of the intestine off a chain reaction that can lead to weight gain, metabolic syndrome (the triad of high cholesterol, high blood pressure and diabetes) and/or inflammatory bowel disease. So researchers used mice in a series of experiments to learn more about what two of the most commonly used food emulsifiers do to the intestinal tract. Their names may be quite familiar to you from reading food labels-carboxymethyl cellulose (also known as cellulose gum) and polysorbate-80.

For 12 weeks, mice were either given drinking water that was mixed with one of the two emulsifiers at concentrations similar to real-world human consumption... or plain water.

The results: Bacteria in mice that drank emulsifier-spiked water could be found clinging to the intestinal epithelium. The mucus barrier was much thinner in most of the mice consuming emulsifiers compared with mice that drank plain water... and they also had a different mix of bacteria than the mice that drank plain water. Carboxymethylcellulose and polysorbate-80 each caused the same type and degree of change to the gut epithelium, mucous membrane and gut microbiome.

Why this matters: Mice that drank emulsifiers ate more and so gained more weight. They also become glucose intolerant, setting them up for diabetes and metabolic syndrome. And the altered mix of bacteria in their gut promoted intestinal inflammation.

The researchers then toyed with the amount of emulsifiers given to the mice to see just how little it takes for the microbiome to react. Just one half of the equivalent amount of carboxymethylcellulose permitted by the FDA for humans led to low-grade inflammation and increased fat. Just one tenth of the amount permitted by the FDA led to weight gain and glucose intolerance. And when the research team switched the experiment by adding emulsifiers to food instead of water, the results were the same.

This study doesn't defy the notion that eating and drinking too much is responsible for weight gain and metabolic syndrome. What it does show is that food additives may be contributing to obesity and intestinal inflammation and the range of problems that come with these conditions.