Scientific Review Supports Safety of Emulsifiers in Relation to the Human Microbiome
In 2007, the National Institutes of Health’s Human Microbiome Project dramatically increased interest in the human gut microbiota, also called the microbiome. Consumers, health professionals and scientists want to know more about the relationship between the microbiome and our health, including how foods and beverages may have an influence on the function and makeup of the microbiome. A review, “Dietary Exposures to Common Emulsifiers and Their Impact on the Gut Microbiota: Is There a Cause for Concern?,”1 published in the journal Comprehensive Reviews in Food Science and Food Safety, provided an update on the science related to how select food ingredients known as emulsifiers, affect the microbiome. The study’s authors found that this category of food ingredients does not pose any negative effect on the microbiome.
What is the microbiome?
The microbiome is the collection of trillions of microorganisms, mainly found in the gastrointestinal tract. Developedat birth, the microbiome rapidly develops over the first three years and continues to change and adapt throughout our lives, changing in response to various factors including diet. While over 1000 species of microorganismshave been identified in the microbiome, there are about 160 within the gut of any one individual. The microbiome plays a key role in human digestion and metabolism by contributing enzymes not produced by the body to help break down polysaccharides and polyphenols, and synthesize vitamins.
Diet and the Microbiome
Research shows that the gut microbiome changes in response to diet, both in the short- and long-term. But what do these changes mean? Overall, studies indicate that the composition and function of the microbiome is modified by diet. However, everyone responds differently to various dietary components and that includes our microbiomes. Therefore, in order to properly assess the effects of individual ingredients or components of a diet on the microbiome, it is critical that the diets of subjects participating in such studies are carefully controlled, and subjects’ usual, or baseline, diets are well documented and understood.
What are emulsifiers?
Given the recent questions around diet and the microbiome, specifically around emulsifiers, Vo et al.1conducted a literature search to review the existing scientific evidence on how emulsifiers impact the microbiome. The ingredients in this review include:
- Carboxymethyl cellulose
- Polysorbate 80
- Gum Arabic
These emulsifiers are often used in foods for the purposes of achieving preferred flavors or to improve texture, stability and shelf life. Without emulsifiers, packaged foods such as salad dressings, chocolate bars and ice cream would not exist. The ubiquity of these ingredients in the food supply has drawn increased questioning related to health-outcomes that are often associated with dietary patterns, including type 1 and type 2 diabetes, metabolic disease and irritable bowel disease (IBD). Changes in the microbiome, regarding structure and function have been observed in populations with metabolic syndrome, which includes disease states such as obesity, hypertension, diabetes, and cardiovascular disease.
So what does the science tell us?
In short, there is limited evidence indicating adverse effects of emulsifiers on the microbiome. This is due to a number of issues including:
- There are inconsistencies in the methodologies used to analyze the microbiome between studies. The differing techniques used from study to study affect the bacteria that are identified and at what abundance. Thus, there are inconsistent findings and interpretations that follow.
- Anatomical and physiological differences in the gastrointestinal tract of rodents and humans makes it difficult to extrapolate findings in rodents to humans.
- Test diets provided to laboratory animals can be controlled in animal studies while the human diet cannot be adequately controlled.
- There is no alignment on what type of changes in the microbiome qualify as being adverse.
The researchers of this review suggest that an established and agreed upon range of different microorganisms within the microbiome would help to provide a reference for future studies in the interpretation and clinical relevance of changes observed in response to various dietary components and ingredients. Given this, the researchers state that they have found that consumption of foods with emulsifiers do not pose any safety concerns and that their history of safe use is not brought into question by the existing scientific literature.