Emulsifiers are the most widely used food additive. What are they doing to our gut microbiome?
Are Emulsifiers Like Carboxymethylcellulose and Polysorbate 80 Safe?
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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Today, when grocery shopping, unless you’re sticking to the produce aisle, “[it’s] nearly impossible to avoid processed foods, particularly …” if you’re eating the standard American diet, characterized not only by insufficient plant foods and too much meat, dairy, and eggs, but also lots of processed junk; and along with that, an “increased exposure to [food] additives…”.
For example, the artificial sweetener sucralose, sold as Splenda, can disrupt the human gut microbiome, and “induce glucose intolerance.” In other words, it can make your blood sugars worse instead of better. It’s relatively easy to avoid artificial sweeteners, but “it may be … more difficult to avoid ingestion of emulsifiers … because they are commonly added to [so many] foods.” In fact, “emulsifiers are the most widely used food additives,” and “most processed foods contain one or more [of them].” We now consume emulsifiers by the megaton every year, thanks to a multibillion-dollar industry.
You’ll commonly find emulsifiers in fatty dressings, fatty spreads, baked goods, mayonnaise, salad dressing, candy, and beverages. Why do we care? “Like all authorized food additives, emulsifiers have been evaluated by risk assessors, who consider them as safe.” However, there are growing concerns among scientists about their [potentially] harmful effects on [our intestinal barrier]” in terms of causing a leaky gut, as well as their effects on our microbiome. Moreover, they could possibly “increase the absorption of … environmental toxins” present in the food.
We know that the consumption of ultra-processed foods may be a contributor to weight gain, for example. Healthier, longer-lived populations don’t just have low meat intake and high plant intake, but they are eating minimally-processed foods. Maybe the emulsifiers found in processed foods could be playing a role, based on a number of preclinical studies. But who cares if “emulsifiers make rats gain weight”? When you read that “emulsifiers can cause striking changes in the microbiota,” they’re not talking about within human beings.
Mice are often used to study diet’s impact on the microbiome, but we only share “a few percent of … bacterial genes” in common. Even the gut flora of different mouse strains can be considerably different from each other, so if you can’t even extrapolate from one type of mouse to another, how are you supposed to translate results from mice to human beings? “Remarkably, there has been little study of the potential harmful effects of ingested . . . emulsifiers in [us].”
For example, lecithin, perhaps best known as a key component of egg yolks, was found to be worse than polysorbate 80 in terms of allowing bacteria to leak through the gut wall into the bloodstream. But whether lecithin consumption in humans causes the same problem is yet to be determined. “There is certainly a paucity … of human trials [on] the effects of emulsifiers in processed foods,” but we at least have data on human tissue, cells, and gut flora.
“Dietary emulsifiers directly alter the [composition of the human microbiome]…ex vivo…potentiating intestinal inflammation”. Ex vivo means outside the body. Researchers inoculated an artificial gut with fresh human feces until they had a nice stable culture going, and then added carboxymethylcellulose or polysorbate 80, and got a boost in proinflammatory potential, starting within one day with the carboxymethylcellulose, and within the first week with polysorbate 80. “This approach revealed that both [emulsifiers] acted directly upon human gut [bugs] to increase [their] proinflammatory potential.” If you then test the effect of these emulsifiers on the protective mucus layer in petri dish cultures of human gut lining cells, you will find they can partially disrupt the protecting layer. The green staining is the mucus, and both emulsifiers cut down the levels. But both this study and the last-used emulsifier concentrations were far in excess of what people might typically get day-to-day.
This is probably the study that raised the greatest potential concern. The researchers surgically obtained not just cells, but actual intestinal wall tissue, and found that polysorbate 80 could double the invasion of E. coli through the intestinal lining tissue, whereas adding fiber (in this case, fiber from plantains) could seal up the gut wall tissue twice as tight.
Please consider volunteering to help out on the site.
- Partridge D, Lloyd KA, Rhodes JM, Walker AW, Johnstone AM, Campbell BJ. Food additives: Assessing the impact of exposure to permitted emulsifiers on bowel and metabolic health - introducing the FADiets study. Nutr Bull. 2019;44(4):329-49.
- Schiffman SS, Nagle HT. Revisited: Assessing the in vivo data on low/no-calorie sweeteners and the gut microbiota. Food Chem Toxicol. 2019;132:110692.
- Suez J, Korem T, Zeevi D, et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014;514(7521):181-6.
- Laster J, Bonnes SL, Rocha J. Increased use of emulsifiers in processed foods and the links to obesity. Curr Gastroenterol Rep. 2019;21(11):61.
- Chassaing B, Vijay-Kumar M, Gewirtz AT. How diet can impact gut microbiota to promote or endanger health. Curr Opin Gastroenterol. 2017;33(6):417-21.
- Miclotte L, Van de Wiele T. Food processing, gut microbiota and the globesity problem. Crit Rev Food Sci Nutr. 2020;60(11):1769-82.
- Lock JY, Carlson TL, Wang CM, et al. Acute exposure to commonly ingested emulsifiers alters intestinal mucus structure and transport properties. Sci Rep. 2018;8:10008.
- Vo TD, Lynch BS, Roberts A. Dietary exposures to common emulsifiers and their impact on the gut microbiota: Is there a cause for concern? Compr REv Food Sci Food Saf. 2018;18(1):31-47.
- Csaki KF, Sebestyen E. Who will carry out the tests that would be necessary for proper safety evaluation of food emulsifiers? Food Sci Hum Wellness. 2019; 8(2):126-35.
- Laster J, Frame LA. Beyond the calories-Is the problem in the processing? Curr Treat Options Gastroenterol. 2019;17(4):577-86.
- Hugenholtz F, de Vos WM. Mouse models for human intestinal microbiota research: A critical evaluation. Cell Mol Life Sci. 2018;75(1):149-60.
- Chassaing B, Van de Wiele T, De Bodt J, Marzorati M, Gewirtz AT. Dietary emulsifiers directly alter human microbiota composition and gene expression ex vivo potentiating intestinal inflammation. Gut. 2017;66(8):1414-27.
- Shurney D, Pauly K. The gut microbiome and food as medicine: healthy microbiomes = Healthy humans. Am J Health Promot. 2019;33(5):821-4.
- Swain Ewald HA, Ewald PW. Natural selection, the microbiome, and public health. Yale J Biol Med. 2018;91(4):445-55.
- Roberts CL, Keita AV, Duncan SH, et al. Translocation of Crohn's disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers. Gut. 2010;59(10):1331-9.
Video production by Glass Entertainment
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Today, when grocery shopping, unless you’re sticking to the produce aisle, “[it’s] nearly impossible to avoid processed foods, particularly …” if you’re eating the standard American diet, characterized not only by insufficient plant foods and too much meat, dairy, and eggs, but also lots of processed junk; and along with that, an “increased exposure to [food] additives…”.
For example, the artificial sweetener sucralose, sold as Splenda, can disrupt the human gut microbiome, and “induce glucose intolerance.” In other words, it can make your blood sugars worse instead of better. It’s relatively easy to avoid artificial sweeteners, but “it may be … more difficult to avoid ingestion of emulsifiers … because they are commonly added to [so many] foods.” In fact, “emulsifiers are the most widely used food additives,” and “most processed foods contain one or more [of them].” We now consume emulsifiers by the megaton every year, thanks to a multibillion-dollar industry.
You’ll commonly find emulsifiers in fatty dressings, fatty spreads, baked goods, mayonnaise, salad dressing, candy, and beverages. Why do we care? “Like all authorized food additives, emulsifiers have been evaluated by risk assessors, who consider them as safe.” However, there are growing concerns among scientists about their [potentially] harmful effects on [our intestinal barrier]” in terms of causing a leaky gut, as well as their effects on our microbiome. Moreover, they could possibly “increase the absorption of … environmental toxins” present in the food.
We know that the consumption of ultra-processed foods may be a contributor to weight gain, for example. Healthier, longer-lived populations don’t just have low meat intake and high plant intake, but they are eating minimally-processed foods. Maybe the emulsifiers found in processed foods could be playing a role, based on a number of preclinical studies. But who cares if “emulsifiers make rats gain weight”? When you read that “emulsifiers can cause striking changes in the microbiota,” they’re not talking about within human beings.
Mice are often used to study diet’s impact on the microbiome, but we only share “a few percent of … bacterial genes” in common. Even the gut flora of different mouse strains can be considerably different from each other, so if you can’t even extrapolate from one type of mouse to another, how are you supposed to translate results from mice to human beings? “Remarkably, there has been little study of the potential harmful effects of ingested . . . emulsifiers in [us].”
For example, lecithin, perhaps best known as a key component of egg yolks, was found to be worse than polysorbate 80 in terms of allowing bacteria to leak through the gut wall into the bloodstream. But whether lecithin consumption in humans causes the same problem is yet to be determined. “There is certainly a paucity … of human trials [on] the effects of emulsifiers in processed foods,” but we at least have data on human tissue, cells, and gut flora.
“Dietary emulsifiers directly alter the [composition of the human microbiome]…ex vivo…potentiating intestinal inflammation”. Ex vivo means outside the body. Researchers inoculated an artificial gut with fresh human feces until they had a nice stable culture going, and then added carboxymethylcellulose or polysorbate 80, and got a boost in proinflammatory potential, starting within one day with the carboxymethylcellulose, and within the first week with polysorbate 80. “This approach revealed that both [emulsifiers] acted directly upon human gut [bugs] to increase [their] proinflammatory potential.” If you then test the effect of these emulsifiers on the protective mucus layer in petri dish cultures of human gut lining cells, you will find they can partially disrupt the protecting layer. The green staining is the mucus, and both emulsifiers cut down the levels. But both this study and the last-used emulsifier concentrations were far in excess of what people might typically get day-to-day.
This is probably the study that raised the greatest potential concern. The researchers surgically obtained not just cells, but actual intestinal wall tissue, and found that polysorbate 80 could double the invasion of E. coli through the intestinal lining tissue, whereas adding fiber (in this case, fiber from plantains) could seal up the gut wall tissue twice as tight.
Please consider volunteering to help out on the site.
- Partridge D, Lloyd KA, Rhodes JM, Walker AW, Johnstone AM, Campbell BJ. Food additives: Assessing the impact of exposure to permitted emulsifiers on bowel and metabolic health - introducing the FADiets study. Nutr Bull. 2019;44(4):329-49.
- Schiffman SS, Nagle HT. Revisited: Assessing the in vivo data on low/no-calorie sweeteners and the gut microbiota. Food Chem Toxicol. 2019;132:110692.
- Suez J, Korem T, Zeevi D, et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014;514(7521):181-6.
- Laster J, Bonnes SL, Rocha J. Increased use of emulsifiers in processed foods and the links to obesity. Curr Gastroenterol Rep. 2019;21(11):61.
- Chassaing B, Vijay-Kumar M, Gewirtz AT. How diet can impact gut microbiota to promote or endanger health. Curr Opin Gastroenterol. 2017;33(6):417-21.
- Miclotte L, Van de Wiele T. Food processing, gut microbiota and the globesity problem. Crit Rev Food Sci Nutr. 2020;60(11):1769-82.
- Lock JY, Carlson TL, Wang CM, et al. Acute exposure to commonly ingested emulsifiers alters intestinal mucus structure and transport properties. Sci Rep. 2018;8:10008.
- Vo TD, Lynch BS, Roberts A. Dietary exposures to common emulsifiers and their impact on the gut microbiota: Is there a cause for concern? Compr REv Food Sci Food Saf. 2018;18(1):31-47.
- Csaki KF, Sebestyen E. Who will carry out the tests that would be necessary for proper safety evaluation of food emulsifiers? Food Sci Hum Wellness. 2019; 8(2):126-35.
- Laster J, Frame LA. Beyond the calories-Is the problem in the processing? Curr Treat Options Gastroenterol. 2019;17(4):577-86.
- Hugenholtz F, de Vos WM. Mouse models for human intestinal microbiota research: A critical evaluation. Cell Mol Life Sci. 2018;75(1):149-60.
- Chassaing B, Van de Wiele T, De Bodt J, Marzorati M, Gewirtz AT. Dietary emulsifiers directly alter human microbiota composition and gene expression ex vivo potentiating intestinal inflammation. Gut. 2017;66(8):1414-27.
- Shurney D, Pauly K. The gut microbiome and food as medicine: healthy microbiomes = Healthy humans. Am J Health Promot. 2019;33(5):821-4.
- Swain Ewald HA, Ewald PW. Natural selection, the microbiome, and public health. Yale J Biol Med. 2018;91(4):445-55.
- Roberts CL, Keita AV, Duncan SH, et al. Translocation of Crohn's disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers. Gut. 2010;59(10):1331-9.
Video production by Glass Entertainment
Motion graphics by Avo Media
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Are Emulsifiers Like Carboxymethylcellulose and Polysorbate 80 Safe?
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For more on food additives, check out:
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- Titanium Dioxide and Inflammatory Bowel Disease
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- Is Caramel Color Carcinogenic?
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