Two Common Food Additives Linked to Obesity And Gut Inflammation

What if the foods we eat every day—without a second thought—are quietly reshaping our bodies and health in ways we never imagined?

A new study published in Nature suggests that two common food additives—carboxymethylcellulose (CMC) and polysorbate-80 (P80)—could be fueling obesity, gut inflammation, and metabolic diseases.

These emulsifiers, found in everything from mayonnaise and ice cream to salad dressings and packaged baked goods, act like detergents to keep ingredients mixed together.

But what they’re doing inside our bodies might be far more alarming.

In lab experiments, researchers found that even tiny amounts of these emulsifiers disrupted gut bacteria in mice, triggering weight gain, glucose intolerance, and increased inflammation.

Even more concerning?

The levels used in the study were well below the concentrations currently approved for human consumption.

With irritable bowel syndrome (IBS), obesity, and metabolic disorders on the rise, this research forces us to ask a critical question:

Are the very foods designed for convenience and shelf stability sabotaging our health?

Let’s break down the science behind the study—and why it’s making experts rethink the safety of processed foods.

How Emulsifiers Could Be Changing Your Gut—And Your Waistline

Over the last few years, researchers have discovered just how crucial our gut microbiome—the trillions of bacteria in our intestines—is to overall health.

A balanced gut microbiome helps regulate digestion, immune function, and even mental health.

But when this delicate balance is disrupted, it can trigger a cascade of health problems, including chronic inflammation, metabolic dysfunction, and weight gain.

That’s exactly what researchers at Georgia State University found when they tested emulsifiers on lab mice.

What Happened to the Mice?

Led by Andrew Gewirtz, the team added carboxymethylcellulose (CMC) and polysorbate-80 (P80) to the drinking water of lab mice.

Here’s what they found:

Healthy mice that consumed emulsifiers became obese and developed glucose intolerance—a key precursor to diabetes.
Mice predisposed to inflammatory bowel disease (IBD) saw an increase in the severity and frequency of symptoms.
Even at just one-tenth of the concentration allowed by the FDA, the emulsifiers still caused gut microbiome disruption.
Mice consuming emulsifiers at human-equivalent levels (such as those who eat processed foods regularly) experienced the most severe effects.

When the researchers analyzed the gut bacteria of these mice, they noticed two major red flags:

A dramatic loss of microbial diversity—a key marker of gut health.
Bacteria moving dangerously close to gut cells—which can lead to inflammation and metabolic dysfunction.

At first glance, this might seem like a concern that only applies to rodents.

But consider this: Mice and humans share surprisingly similar digestive and immune systems.

Studies like this provide important clues about how these chemicals might be affecting us as well.

Wait—Aren’t Food Additives Supposed to Be Safe?

For decades, the food industry and regulatory agencies have reassured us that food additives are thoroughly tested for safety.

Emulsifiers like CMC and P80 have been used in processed foods for years without any obvious, large-scale health crisis.

But here’s the catch: Most safety tests focus on short-term toxicity—not long-term gut microbiome changes.

Until recently, scientists weren’t even looking at how food additives interact with gut bacteria.

This means that while these emulsifiers may not be acutely toxic, they could still be silently wreaking havoc on our digestive and metabolic health over time.

Consider this: Over the past 50 years, conditions like IBS, metabolic syndrome, and obesity have skyrocketed.

Could the widespread use of emulsifiers in processed foods be part of the problem?

The Problem With Processed Foods Isn’t Just Sugar and Fat

We’ve long been told that excess calories, sugar, and fat are the primary drivers of obesity and metabolic disease.

But this study suggests that it’s not just what’s in our food—it’s what’s been added to it.

A growing body of research now points to food additives as hidden disruptors of our gut health.

A 2014 study linked artificial sweeteners like aspartame and sucralose to changes in gut bacteria, leading to glucose intolerance.
Studies on preservatives, such as sodium benzoate, have shown they can alter gut microbiota and contribute to metabolic disorders.
Research on ultra-processed foods has found that people who eat them regularly have a higher risk of obesity, diabetes, and heart disease—even when controlling for calorie intake.

In other words, the problem with processed foods isn’t just the obvious culprits—it’s also the invisible ones, like emulsifiers, that are subtly reshaping our gut and metabolism.

Are Human Trials on the Horizon?

While the evidence in mice is compelling, human trials are needed to determine the full impact of emulsifiers on our gut health.

Currently, researchers are planning to study:

How emulsifiers affect human gut bacteria over time
Whether people who consume high amounts of emulsifiers have a higher risk of metabolic disorders
If eliminating emulsifiers from the diet improves gut health and inflammation markers

Meanwhile, experts like Andrew Gewirtz are already advising caution:

“When it comes to people making their own decisions, between our studies and others out there, it’s better to eat less processed food.”

Translation?

The safest bet is to minimize ultra-processed foods until we have clearer answers.

5 Ways to Protect Your Gut Health

Until more research is done, here are five simple ways to reduce your exposure to emulsifiers and protect your gut microbiome:

1. Read Ingredient Labels

Look out for carboxymethylcellulose (CMC), polysorbate-80 (P80), and other emulsifiers like soy lecithin, carrageenan, and mono- and diglycerides.

If they’re listed among the first few ingredients, consider a less-processed alternative.

2. Choose Whole, Unprocessed Foods

The best way to avoid additives?

Stick to real, whole foods—fresh fruits, vegetables, lean proteins, and healthy fats.

3. Opt for Homemade Versions

Love salad dressings, sauces, or baked goods?

Making them from scratch lets you skip the unnecessary emulsifiers.

4. Support Your Gut with Prebiotics and Probiotics

Foods like yogurt, kefir, sauerkraut, and fiber-rich veggies help nourish your gut bacteria and counteract some of the effects of processed foods.

5. Pay Attention to How You Feel

If you suffer from bloating, digestive discomfort, or metabolic issues, try cutting out emulsifier-heavy foods and see if your symptoms improve.

A Silent Culprit in the Rise of Chronic Disease?

This research adds to the growing realization that what we eat impacts far more than just our calorie count.

While emulsifiers help keep food looking fresh and stable, they might be disturbing our gut microbiome in ways we’re only beginning to understand.

If these findings hold true in humans, we may need to rethink how we define “safe” food additives.

For now, the best advice is simple: Stick to whole, minimally processed foods whenever possible. Your gut—and your long-term health—will thank you.