Our genes and our environment both contribute to our gut microbiome, allowing some species to flourish and keeping others away. How does this all come together to cause the diseases that plague our modern society?
Emulsifiers, Packaged Foods, Inflammation
Recently, I listened to an interview (from March 2015) of a scientist who did a study on emulsifiers and found that they can lead to low-grade inflammation in the gut, especially in mice with certain immune system genes knocked out. That led me to investigate the link between our genetic variants, emulsifiers commonly found in processed foods, and intestinal inflammation.[ref]
What are emulsifiers?
Emulsifiers help solve the age-old problem of getting water and oil to mix. Consisting of a water-loving and oil-loving end, emulsifiers are molecules that are attracted to both oil and water.
Egg yolks are an example of a natural emulsifier.
Some of the first emulsifiers patented for use in foods were a derivative of fatty acids called mono- and diglycerides. Several patents from the 1930’s show mono- and diglycerides being used for shortening – you know, like the Crisco your mom used to use in cookies. Cottonseed oil was cheap and abundant and became the oil of choice in shortening, used instead of lard in baking bread, cakes, and cookies.
These days emulsifiers are used to make food shelf stable with a good texture. You’ll find emulsifiers on the ingredients labels for:
- most baked goods
- ice cream
- some deli meats
- pickled products
- salad dressings
- coffee creamer
- and more!
Emulsifiers can also act as surfactants, which reduce surface tension. Surfactants are commonly found in detergents – think about a drop of dish detergent breaking up the grease in a pan.
Commonly used emulsifiers:
- also known as CMC or cellulose gum,
- GRAS (generally regarded as safe) by the FDA
- allowed to be included at up to 2% in various foods
“CMC is used in food under the E number E466 as a viscosity modifier or thickener, and to stabilize emulsions in various products including ice cream. It is also a constituent of many non-food products, such as toothpaste, laxatives, diet pills, water-based paints, detergents, textile sizing, and various paper products. It is used primarily because it has high viscosity, is nontoxic, and is generally considered to be hypoallergenic as the major source fiber is either softwood pulp or cotton linter. CMC is used extensively in gluten free and reduced fat food products.”Wikipedia
- also known as P80 or Tween 80
- allowed at levels up to 1% in certain foods
Polysorbate 80 is a surfactant and emulsifier used in foods and cosmetics. Ice cream often includes polysorbate 80 (up to 0.5%) to help it stay smooth. It is also found in a lot of pickles and pickled products.
The acceptable daily intake (World Health Organization) is 25 mg/kg body weight/day, acute toxicity is low, and it is not considered cancer causing.
So why would these ‘generally regarded as safe’ ingredients cause a problem? It all starts in the gut (combined with genetics).
A little background on the gut:
The intestinal wall is lined with epithelial cells along with a mucosal barrier to keep out microbes and to protect against digestive enzymes.
While it sounds a little icky, the mucosal barrier keeps microbes away from the epithelial cells and thus out of the body’s circulation. The microbes in our guts are important and perform a variety of functions for us, including making some vitamins and short-chain fatty acids. But they have to stay in the right spot in the gut…
When the mucosal barrier is disrupted, the immune system gets activated by gut microbes, thus causing an inflammatory response.
This can lead to autoimmune and inflammatory conditions such as food intolerances, IBD, and diabetes.
So, if a dysfunctional mucosal barrier can cause intestinal and autoimmune disorders, what does a thinner than normal barrier do? According to a scientist at Georgia State University, it causes low-level inflammation, which could be driving weight gain and metabolic syndrome.
Studies of Emulsifiers and the Gut Microbiome:
Decades ago, researchers investigated the toxicity and cancer-causing properties of carboxymethyl cellulose, hydroxypropyl methylcellulose, and polysorbate 80. [ref][ref][ref] These emulsifiers were found to be acceptable for use as food additives.[ref][ref][ref] They have been identified as safe for human consumption by the FDA.
But several new studies within the last couple of years have been looking at the chronic, low dose effect of emulsifiers on the intestinal mucosal barrier. These studies paint a new picture of the health effects of the emulsifiers.
Studies on chronic effects of emulsifiers/surfactants:
- Researchers looked at whether emulsifiers (specifically Carboxymethylcellulose and Polysorbate 80) increased low-grade inflammation, resulting in metabolic syndrome. The results showed:
- Carboxymethylcellulose in low levels (0.1 – 0.5% of their food) increased body weight and caused low-grade inflammation.
- Polysorbate 80 in low levels (0.1 – 0.5% of their food) also increased body weight and caused low-grade inflammation. At the 0.5% level, polysorbate 80 caused dysglycemia.
- Most importantly, the “Emulsifier-induced metabolic syndrome was also observed in older mice… and persisted for at least 6 weeks after stopping emulsifier consumption”.
- To sum up, the emulsifiers used in this study caused bacteria to be located closer to the epithelial cells of the intestine. For mice that were genetically susceptible to colitis, this caused colitis. For normal mice, this caused low-grade inflammation, fat gain, and mild blood sugar level issues.
- Researchers found emulsifiers caused impaired glycemic tolerance, increased gall bladder size, and reduced intestinal mucosa thickness. The reduced mucosal thickness cause intestinal bacteria to be closer to the epithelial cells and increased inflammation.
- Researchers found food additives such as emulsifiers, organic solvents, gluten, and nanoparticles used in processed food increased the intestinal permeability. Essentially – they caused leaky gut.
- This study looked at the effect of non-starch polysaccharides vs. food emulsifiers on the ability of E. coli to the mucosa in the intestinal tract. The study found that:
- plant fibers, such as broccoli and plantain, reduced E. coli moving into the intestinal cells
- the addition of polysorbate 80 at 0.01% increased E. coli translocation by 59-fold
- This research study (in mice) demonstrated that “regular consumption of dietary emulsifiers, carboxymethylcellulose or polysorbate-80, exacerbated tumor development…. We found that emulsifier-induced alterations in the microbiome were necessary and sufficient to drive alterations in major proliferation and apoptosis signaling pathways thought to govern tumor development.”
The key as to whether emulsifiers cause intestinal barrier leakiness in people is dependent on genetics. Some (perhaps most) people can eat foods containing emulsifiers without any issues.
Genetic variants impacted by emulsifiers:
The mouse studies (above) that link emulsifiers to decreased mucosal barrier and inflammation in the gut all focused on genetic variants in IL10 and NOD2. These two genes, in humans, are strongly linked to inflammatory bowel disease.
IL10 is the gene that codes for interleukin 10, an anti-inflammatory cytokine. It prevents the immune system from reacting too strongly or inappropriately. It has been known for more than 20 years that “In the absence of IL-10, spontaneous mucosal autoimmunity develops, while the effect on systemic autoimmunity is far more muted”. [ref]
Check your genetic data for rs1800871 -819T>C (23andMe v4, v5; AncestryDNA):
- G/G: increase inflammation, increase risk of inflammatory bowel disease[ref][ref]
- A/G: slightly increased inflammation, increased risk IBD
- A/A: typical
Members: Your genotype for rs1800871 is —.
Check your genetic data for rs3024505 (23andMe v4, v5; AncestryDNA):
- A/A: increased risk of inflammatory bowel disease[ref][ref]
- A/G: slightly increased risk of inflammatory bowel disease
- G/G: typical
Members: Your genotype for rs3024505 is —.
Check your genetic data for rs1800896 -1082A>G (23andMe v4, v5; AncestryDNA):
- C/C: increased inflammation, increased risk of inflammatory bowel disease[ref][ref][ref]
- C/T: slightly increased inflammation, increased risk IBD
- T/T: typical
Members: Your genotype for rs1800896 is —.
NOD2 genetic variants:
NOD2 polymorphisms are a risk factor for Crohn’s Disease. The variants lead a defective inflammatory response in the intestinal wall. Studies (above and here) show that the emulsifier polysorbate 80 increases adherent invasive E. coli, which increases inflammation and the risk for Crohn’s Disease.
Check your genetic data for rs2066844 R720W (23andMe v4, v5)
- T/T: significantly increased risk of Crohn’s [ref]
- C/T: increased risk of Chron’s disease
- C/C: typical
Members: Your genotype for rs2066844 is —.
Check your genetic data for rs2066845 (23andMe v4; AncestryDNA):
- C/C: significantly increased risk of Crohn’s[ref]
- C/G: increased risk of Chron’s disease
- G/G: typical
Members: Your genotype for rs2066845 is —.
Check your genetic data for rs2066847 (23andMe v4):
- I/I: significantly increased risk of Crohn’s[ref]
- D/I: increased risk of Chron’s disease
- D/D: typical
Members: Your genotype for rs2066847 is —.
To be honest, avoiding emulsifiers in foods is labor intensive and inconvenient. Eating out becomes nearly impossible, and a trip to the grocery store means time spent reading all the labels. Could it be worth it? For some people, yes.
The biggest source of methylcellulose for a lot of health nuts seems to be in supplements. Most capsules are made of cellulose instead of gelatin these days (so that they are vegetarian friendly). Quite a few tablets include either CMC or polysorbate 80.
The pharmaceutical industry uses many of the same food grade emulsifiers to enhance the bioavailability of their drugs. The mucosal intestinal barrier is something that drugs must overcome, and adding in emulsifiers increases their bioavailability.[ref] There are quite a few pharmaceutical studies available on increased absorption due to the use of emulsifiers.[ref][ref][ref][ref][ref]
Apparently, the pharmaceutical industry has known for many, many years that including a surfactant/emulsifier along with the drug increases the absorption in the gut through reducing the mucosal barrier. Quite a few of the most common prescription medicines contain polysorbate 80, carboxymethylcellulose w/ sodium, and methylcellulose. (Note that I’m not encouraging anyone to stop taking a prescription medication just because it contains an emulsifier! Always talk with your doc.)
A cell study using IL10 genetic variants shows that curcumin may decrease the impact on IBD.[ref]
Related Genes and Topics:
HLA-B27: Genetic Variant That Increases Susceptibility to Autoimmune Diseases
Our immune system does an awesome job (most of the time) of fighting off pathogenic bacteria and viruses. But to fight off these pathogens, the body needs to know that they are the bad guys. This is where the HLA system comes in. This article covers background information on HLA-B27 and the genetic variants available in 23andMe or AncestryDNA data.
Histamine Intolerance & Genetics: Check Your 23andMe Raw Data
When your body has too much histamine, it can cause symptoms known as histamine intolerance. This can be due to excess production of histamine by your body or not being able to break down histamine from foods very well. OR… both! Genetics plays a big role in how well your body breaks down histamine!