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Emulsifiers are in many of the processed foods we buy. They are added to the foods to enhance texture and extend shelf life. Animal and human studies find that some emulsifiers (e.g., soy lecithin, carrageenan, polysorbate-80) can promote gut inflammation and alter the gut microbiome in a negative or harmful way. Recent research adds to this list the common emulsifier carboxymethylcellulose (CMC), also known as cellulose gum.

A small study randomly assigned 16 healthy adults to either an emulsifier-free diet or an identical diet with added 15 g per day of CMC for 11 days. No one knew what diet they were eating, and for those 11 days the participants were inpatient - thus no chance for cheating or altering the diet. Extensive testing (even biopsies on day 1 and 11!) was done before, during, and after the study. The Univ. of Pennsylvania researchers found that CMC resulted in several harmful changes, including a negative effect on the gut microbiome (microbial community of bacteria, viruses, fungi).

Results: The researchers found that CMC increased abdominal discomfort after meals, disturbed the gut microbial community and reduced its diversity (not good!). It resulted in reductions of short-chain fatty acids and free amino acids (thus impacted how nutrients are absorbed). One of the beneficial microbes associated with good health, and that was reduced in number was Faecalibacterium prausnitzii.

Two of the subjects who had CMC in their foods had increased microbial "encroachment into the normally sterile inner mucus layer" of the gut, which is a central feature of chronic inflammation diseases (e.g., IBD, type 2 diabetes). They also had large "alterations in microbiota composition". This means that there is variation in how people respond to the emulsifier CMC, with some people more sensitive than others.

The scary part is that the intestinal changes happened after just 11 days with a daily intake of 15 g of CMC - a dose that is approximately the total emulsifier consumption for a person whose diet is largely highly processed food. Yes, that is many of us eating a Western style diet (e.g., highly processed foods, and low in fiber, fresh fruits, vegetables, and whole grains). The scientists believe that long-term consumption of emulsifiers, because they result in gut microbial disruption and inflammation, are contributing to chronic diseases.

Bottom line: Read the ingredients list on food labels. Try to avoid foods that have ingredients listed that you wouldn't normally have in your kitchen. That means soy lecithin, CMC, cellulose gum, carrageenan, artificial colors. Even "natural flavors" (which are laboratory concoctions) should be avoided as much as possible.

From Medical Xpress: Ubiquitous food additive alters human microbiota and intestinal environment

New clinical research indicates that a widely used food additive, carboxymethylcellulose, alters the intestinal environment of healthy persons, perturbing levels of beneficial bacteria and nutrients. These findings, published in Gastroenterology, demonstrate the need for further study of the long-term impacts of this food additive on health.  ...continue reading "Some Emulsifiers Harm the Gut Microbiome"

The American diet with its emphasis on highly processed foods is linked to chronic diseases. It's also not healthy when you look at the microbiome (community of microbes living in your body). With all the health research out there showing health benefits of real whole foods (especially fruits, vegetables, whole grains, seeds, legumes), then the finding that highly processed foods dominate U.S. food purchases are just plain sad. But I'm not surprised. From Science Daily:

Highly processed foods dominate U. S. grocery purchases

A nation-wide analysis of U.S. grocery purchases reveals that highly processed foods make up more than 60 percent of the calories in food we buy, and these items tend to have more fat, sugar and salt than less-processed foods.

From 2000 to 2012, the researchers asked 157,142 households to use UPC barcode scanners to record all foods and beverages they purchased from grocery stores for at least 1 year. Although items without barcodes were not included, Poti points out that packaged produce such bagged lettuce or pints of berries can be scanned. Households participated in the study for an average of four years and collectively purchased 1.2 million items. The research team then linked each item to its nutrition information, product description and ingredient list, allowing them to rank each product's degree of food processing.

The researchers classified products as highly processed if they contained multi-ingredient, industrially formulated mixtures. They labeled foods such as soda, cookies, chips, white bread, candy and prepared meals as highly processed foods and categorized fresh or frozen fruits and vegetables, milk, eggs, dried beans and fresh meat as unprocessed or minimally processed. The investigators also examined convenience, distinguishing between foods that are ready to eat, ready to heat or require cooking and/or preparation. Candy and chips are examples of ready-to-eat foods, and frozen meals are a ready-to-heat food.

"Overall, we found that not only are highly processed foods a dominant, stable part of U.S. purchasing patterns, but also that the highly-processed foods that households are purchasing are higher in fat, sugar, and salt, on average, compared to the less-processed foods that they buy," said Poti, who will present these findings at the American Society for Nutrition (ASN) Annual Meeting during Experimental Biology 2015."

The analysis revealed that from 2000 to 2012, the proportion of calories in highly processed food and beverage purchases by U.S. households remained stable at 61.0 to 62.5 percent. The researchers noted a significant increase in the proportion of calories purchased in ready-to-heat foods, which reached 15.2 percent in 2012. More than 80 percent of calories were purchased in ready-to-eat or ready-to-heat form in 2012, and these tended to be higher in fat, sugar and salt than food purchases that required preparation.

Of course some foods are addictive. Anyone who tries to eat just one french fry or one piece of chocolate or one potato chip knows that it's very, very hard to do that. Do people have raw carrot cravings? Nah... Chocolate cravings? Yup..Does this research really tell us anything new? From Science Daily:

Want pizza, chocolate, French fries? Highly processed foods linked to addictive eating

A new University of Michigan study confirms what has long been suspected: highly processed foods like chocolate, pizza and French fries are among the most addictive.

This is one of the first studies to examine specifically which foods may be implicated in "food addiction," which has become of growing interest to scientists and consumers in light of the obesity epidemic.Previous studies in animals conclude that highly processed foods, or foods with added fat or refined carbohydrates (like white flour and sugar), may be capable of triggering addictive-like eating behavior. Clinical studies in humans have observed that some individuals meet the criteria for substance dependence when the substance is food.

Unprocessed foods, with no added fat or refined carbohydrates like brown rice and salmon, were not associated with addictive-like eating behavior.

Individuals with symptoms of food addiction or with higher body mass indexes reported greater problems with highly processed foods, suggesting some may be particularly sensitive to the possible "rewarding" properties of these foods, said Erica Schulte, a U-M psychology doctoral student and the study's lead author...."This is a first step towards identifying specific foods, and properties of foods, which can trigger this addictive response," she said. "This could help change the way we approach obesity treatment. It may not be a simple matter of 'cutting back' on certain foods, but rather, adopting methods used to curtail smoking, drinking and drug use.