Polysorbate 80 Food Additive, Gut Bacteria, and Inflammation
Linda Crampton is a writer and teacher with a first class honors degree in biology. She often writes about the scientific basis of disease.
What Is Polysorbate 80?
Polysorbate 80 is a common food additive which acts as an emulsifier, a solubilizer, and a surfactant. It's generally—but not universally—considered to be a safe substance, although it may cause problems in special cases. One of these cases is in people with Crohn's disease. In this disease, the lining of the gastrointestinal tract is inflamed. Polysorbate 80 may worsen the inflammation.
Research performed at Georgia State University has raised the idea that polysorbate 80 is not as harmless as is generally believed. The research suggests that the chemical changes the composition of the bacterial population in the intestine, promoting the growth of pro-inflammatory bacteria. These bacteria may cause mild gut inflammation even in people who don't have Crohn's disease. The inflammation may then increase the risk of a person developing metabolic syndrome. This syndrome involves a number of unhealthy conditions, including obesity and insulin resistance. Insulin resistance increases the blood sugar level and is often a precursor to type 2 diabetes.
The tube connecting the mouth to the anus has several names that are used interchangeably. The terms gastrointestinal tract, GI tract, digestive tract, alimentary canal, and gut all refer to the same passageway. The word gut (as in "gut bacteria") usually refers to just the small and large intestine in human biology, however.
A Useful Chemical
Polysorbate 80 is a very useful substance in processed foods. It creates a smooth texture and a great mouthfeel. It also enables substances to mix when they wouldn't normally do so. It's added to health and beauty products, medications, and vaccines as well as foods. It's often referred to an excipient in medications and vaccines. Excipients are substances other than the active ingredient that serve a useful function in a product.
IUPAC (International Union for Pure and Applied Chemistry) has established a naming system for chemicals. According to this system, polysorbate 80's real name is polyoxyethylene (20) sorbitan monooleate. It's a synthetic chemical that is sold in the form of a thick yellow liquid. The chemical is soluble in water as well as in several other liquids.
Polysorbate 80 is used as an emulsifier. An emulsifier enables oils to mix with water instead of staying separated. The emulsifier breaks up oil and fat into small droplets. The oil droplets don't dissolve in water, but they do form a fine dispersion which is appealing in food and cosmetics.
Emulsifiers enable us to enjoy food products such as creamy sauces, mayonnaise, margarine, ice cream, and smooth chocolate. Egg yolk is a natural emulsifier, but it has the disadvantage of a short shelf life. Lecithin from soybeans is also an emulsifier.
A Solubilizer and a Surfactant
Polysorbate 80 is a good solubilizer as well as a good emulsifier. A solubilizer is a substance which increases the solubility of one substance in another, allowing them to mix. The term is often used to describe a substance that increases the ability of oil to dissolve in water.
Polysorbate 80 is also useful as a surfactant. A surfactant lowers the surface tension on the surfaces of liquids. Its name is a contraction of "surface active agent". The molecules at the surface of a liquid bind tightly to each other, producing a phenomenon known as surface tension. Surface tension creates a barrier that prevents some substances from entering the liquid. The barrier also makes it hard for the liquid to mix with other substances. Surfactants such as polysorbate 80 help substances to mix with other substances by reducing the surface tension that is keeping them apart.
What Is Crohn's Disease?
Crohn's disease is a type of inflammatory bowel disease, or IBD. (Bowel is another name for intestine.) The inflammation of the intestine is accompanied by pain, which may be severe and even debilitating. Symptoms of the disease also include diarrhea, malnutrition, weight loss, and fatigue.
The intestinal problem in a patient with Crohn's disease is often in the ileum, which is the last part of the small intestine, or in the first part of the colon, which is the longest part of the large intestine. The symptoms may appear anywhere in the digestive tract, however. Current treatments can be very helpful for some people—though not for everyone—but at the moment there is no cure.
Exploring the Causes of Crohn's Disease
The Possible Role of Bacteria
The cause of Crohn's disease isn't known for certain, although researchers suspect that an abnormally permeable intestinal lining and an overactive immune system are involved. It's thought that the immune system responds inappropriately to microbes such as bacteria in the intestine.
The human intestine is the home of a huge bacterial population. Many of these bacteria are very helpful, but a few are harmful. Normally the effects of the good bacteria overcome the effects of the bad ones. In people with Crohn's disease, the immune system may be overreacting to the presence of harmful microbes or continuing an attack against these microbes (via the inflammatory response) after the microbes have been destroyed.
Although some strains of E. coli are harmful and cause problems such as food poisoning, others are helpful and are normal inhabitants of our large intestine.
Polysorbate 80 and Crohn's Disease
There have been several research projects that suggest a link between polysorbate 80 and Crohn's disease. One project of interest was performed by British researchers and reported in the British Medical Journal.
The researchers explored the effect of polysorbate 80 and soluble plant fibres on the movement ofEscherichia coliinto isolated human cells and tissue in a laboratory. Some strains ofE. colihave been implicated in Crohn's disease. The scientists used M-cells in their experiment. These cells are one of the types present in the intestinal lining and may be the site of bacterial invasion.
The researchers found that polysorbate 80 increased bacterial absorption in both cells from Crohn's disease patients and cells from healthy people. The chemical had a greater effect on the cells from the Crohn's disease patients, however. Electron microscopy confirmed thatE.colihad entered the cells. The researchers also discovered that fibre from broccoli and plantain decreased bacterial absorption in the intestinal cells.
The results imply that polysorbate 80 could worsen Crohn's disease by causing more bacteria to enter the intestinal lining. This may in turn increase the abnormal response to the bacteria and the gut inflammation.
Some Possible Problems With the British Experiment
The British researchers used a low concentration of polysorbate 80 in their experiment. The concentration was equivalent to the amount that might be left in the intestine after digestion in an average person's gut. The actual concentration of the chemical in an individual's gut may be different, however. In addition, the test was done on isolated cells instead of on cells inside the body. Still, the results of the experiment are very interesting.
The Intestinal Microbiome and Its Importance
The human body contains about ten times more bacterial cells than human cells. Bacterial cells are smaller than human ones and tend to gather on the skin and in cavities in the body. Most are found in the large intestine, but some inhabit the small intestine instead or as well. Research suggests that our gut bacteria may have a profound effect on our lives.
About a hundred trillion individual microbes are thought to live in our gut. The microbes in our intestine are mainly bacteria, but there are fungi present as well. Some of the bacteria produce chemicals that we need, such as vitamins. Other help us to digest food. Some appear to boost our immunity or help to control our weight. Others destroy dangerous bacteria that can cause disease. Researchers are discovering that gut bacteria may influence our bodies in additional ways. Any factor that affects the population of "good" bacteria adversely could also affect our health.
The Importance of Gut Flora: 100 Trillion Friends
Gut Bacteria, Inflammation, and Metabolic Syndrome
Research at Georgia State University in the United States adds support to the idea that polysorbate 80 is bad for gut health. The researchers studied the effect of two common emulsifiers on gut bacteria and health in mice. These emulsifiers were polysorbate 80 and carboxymethylcellulose. The scientists gave the mice emulsifiers in an amount equivalent to that in an average human diet.
Change in Gut Bacteria
The researchers found that the composition of the gut bacteria in the mice fed emulsifiers changed and that more pro-inflammatory bacteria appeared. The new bacterial community had an enhanced ability to penetrate the mucus layer covering the cells of the intestinal lining. In addition, the new community made more flagellin and lipopolysaccharide, chemicals that can activate human genes which trigger inflammation.
Gut Inflammation and Metabolic Syndrome
Some of the mice fed the emusifiers had been bred to have immune systems that made them more susceptible to gut inflammation. As a result of the emulsifier diet, these mice developed colitis, or inflammation of the colon. Very interestingly, the mice with normal immune systems developed mild colon inflammation from the emulsifier diet and also developed a disease known as metabolic syndrome, which involves a cluster of different disorders.
Results of a Bacterial Transplant
The Georgia State researchers also fed emulsifiers to mice without bacteria in their intestine and found that the diet had no effect on the state of the gut. When they transplanted bacteria from emulsifier-treated mice into the sterile mice, they found that the sterile mice developed mild gut inflammation and some of the symptoms of metabolic syndrome.
Results in mice are often similar to those obtained in humans, which is one reason why mice are good subjects for experiments. The results are not always the same, however. The Georgia State University researchers are now designing experiments to be used with human subjects.
What Is Metabolic Syndrome?
Metabolic syndrome is a disease in which a mouse or a human experiences at least three of a group of five disorders. The disorders are as follows:
- high fasting blood sugar
- high serum triglycerides (fats)
- high blood pressure
- low HDL cholesterol (the good cholesterol)
- abdominal obesity.
The definition of "high"or "low" in each disorder is determined by a comparison with specific numbers. Metabolic syndrome is a serious condition because it increases the risk of heart problems and strokes. Any factor that increases the risk of the syndrome is undesirable.
A Doctor Describes Metabolic Syndrome
The Problem of Obesity
Researchers have found that obesity is a complex condition. It may not result simply from a person having weak willpower and eating too much food. The cause of obesity may be multifactorial. The Georgia State University scientists suspect that gut inflammation may be one of the factors responsible for the condition. If this is the case, then it's important that the inflammation is prevented, even if the disorder isn't painful.
We need to understand the causes of obesity because the condition is becoming more common in many parts of the world. Metabolic syndrome and obesity are also developing at a younger age and are even appearing in childhood. Researchers are currently talking about an "obesity epidemic".
A Food Additive Poll
Do you avoid buying food or drinks containing food additives?
Processed Food and Food Additives
A diet involving whole, unprocessed, or minimally processed foods is best for several reasons. One is that it's the diet that is most likely to be rich in nutrients. Another is that it lacks food additives, some of which may be harmful.
Removing polysorbate 80 from the diet or limiting its consumption may be only one step that is needed in the path towards improved health. More research is needed to investigate the chemical's behaviour in our body and to clarify any of its detrimental effects. There is ample evidence indicating that a healthy diet comprised of mainly unprocessed and natural foods is good for us, however. It seems like a good idea to follow this diet as often as possible, which will automatically decrease the amount of food additives that we consume.
- Uses of Polysorbate 80 from the FDA (U.S. Food and Drug Administration)
- Translocation ofEscherichia colifrom the BMJ (British Medical Journal)
- Georgia State University. (2015, February 25). Widely used food additives promotes colitis, obesity and metabolic syndrome, shows study of emulsifiers.ScienceDaily.