Do you need another reason to stay away from processed foods? A study in Nature (Feb 2015) links a diet containing emulsifiers to microbiome changes, intestinal inflammation, obesity and autoimmune disease. So put down that Twinkie and read on.
What are emulsifiers?
Oil and water don’t mix. No matter how well stirred, they eventually separate into ugly, unpalatable layers. In the world of processed foods, this is not cool. The solution is to add emulsifiers, which are molecules with a hydrophilic (water-attracting) and a hydrophobic (oil-attracting) end. The emulsifiers bind water to oil and fats, much like the steely grip of a mother holding the hands of two squabbling children. They aren’t going anywhere. The emulsifier stabilizes the end food product, giving it a homogenous texture and a longer shelf life.
Because they are so useful, emulsifiers are found in most processed foods. Natural emulsifiers include eggs (used in baked goods) and beeswax (used in cosmetics). The food industry has created artificial emulsifiers such as carrageenan, lecithin, polysorbate-80, polyglycerols, and xanthan gum. Look for them in any processed food like ice cream, margerine and other dairy products, mayonnaise and salad dressings, packaged breads and other baked goods, and even most almond milks.
What did this study show?
This study by researchers at Georgia State University specifically looked at the effect of dietary emulsifiers on the intestinal health of mice. Mice were fed either a regular diet or a diet laced with low-doses of a commonly used emulsifier (either polysorbate-80 or carboxymethylcellulose).
Emulsifiers alter the composition of the gut microbiome, with reduced microbial diversity and increased pro-inflammatory bacteria. Previous studies show these microbiome changes are associated with numerous chronic inflammatory diseases, including inflammatory bowel disease (Crohns disease, ulcerative colitis) and obesity/metabolic syndrome.
Emulsifiers reduce the thickness of the protective layer of mucus lining the intestine. Normally, this multi-layered mucus structure protects the epithelial cells lining the intestines, but the detergent-like properties of emulsifiers allow the mucus layer to break down, causing pro-inflammatory bacteria to have more contact with the intestinal epithelium.
Emulsifiers increase gut permeability as evidenced by an increase in specific circulating antibodies in the blood. In theory, this makes sense, as the pharmaceutical industry uses emulsifiers to increase intestinal permeability (by widening the tight junctions connecting epithelial cells to their neighbors) so that medications can be better absorbed. Yet increased intestinal permeability is also a major player in the development of autoimmune diseases.
In wild type (“normal” genes) mice, emulsifiers cause a low-grade intestinal inflammation. This led to features of metabolic syndrome, including blood glucose level elevation, modest but significant weight gains, and increased abdominal fat.
In mice genetically susceptible to autoimmune disease, emulsifiers caused a robust colitis. This colitis is the mouse model for the human equivalent, Crohns disease (an autoimmune inflammatory bowel disease).
The changes in the microbiome and the intestinal inflammation happened even at low levels (0.1 – 1%) of emulsifier intake. Of note, the FDA approves human intake of polysorbate-80 of up to 1% of foods and carboyxymethylcellulose up to 2%. The changes seen occurred within 4 weeks of a chronic ingestion and persisted for at least 6 weeks after emulsifier consumption stopped.
What does this mean for our consumption of emulsifiers?
The study provides strong evidence that common food additives, emulsifiers, are linked to microbiome changes, intestinal inflammation, obesity and autoimmune colitis in mice. Its raises a red flag that emulsifiers contribute to autoimmune disease. It’s a big leap from one basic science study to generalized clinical impact, however, and this article raises many questions:
- Can we extrapolate that emulsifiers are harmful to humans?
- Can we extrapolate that other emulsifiers are also harmful?
- In linking emulsifiers to autoimmune colitis, can we extrapolate that they can cause other autoimmune diseases?
- Are emulsifiers a main contributer to autoimmune disease or are they one of many environmental triggers?
- On an individual level, what amount of emulsifiers are we ingesting in our diets?
The FDA, which is charged with declaring foods safe for our ingestion, makes these decisions despite lacking adequate testing for the majority of food additives. Polysorbate-80 has been tested for acute toxicity and cancer-causing potential; carboxymethylcellulose has not been studied. Neither emulsifier was tested for immune system impact prior to approval. To add insult to injury, any testing that occurs is done by the companies that make the product, not by the FDA itself. Ultimately, the FDA assumes that a food additive is safe unless proven otherwise, which is good for the food industry but bad for consumer health.
Wellness advocates have long reported the ill effects of emulsifiers, but this study brings evidence to the medical community that ingesting emulsifiers may be harmful to our health. Emulsifiers aren’t nutrients, however. They are just added to food products to make them more convenient. Therefore, it may be prudent to avoid emulsifiers until they are proven to be safe.
Emulsifiers are ubiquitous in processed foods. This study in mice provides evidence that a diet containing chronic, low-dose, artificial emulsifiers promotes autoimmune disease via altering the gut microbiome, increasing gut permeability, and degrading the protective layer of mucus in the intestines. Until emulsifiers are proven safe, people with or at risk for autoimmune disease should consider avoiding them in their diet. The easiest way to do this is to avoid processed foods.
List of Common Artificial Emulsifiers:
Mono- and di-glycerides of fatty acids
Polyglycerol esters of fatty acids
Polysorbates (20, 40, 60 & 80)
Propylene glycol monostearate
Sorbitan esters of fatty acids
Xanthan gum and other gums