Study reveals link between ultra-processed foods and gut health risks

In a recent review published in a magazine Nature Reviews Gastroenterology and Hepatologyresearchers synthesized current knowledge about how food additives and ultra-processed foods (UPFs) affect gut health.

As UPF and food additives become more common in diets around the world, they are implicated in adverse intestinal effects such as changes in microbial communities and intestinal permeability, leading to chronic inflammation, inflammatory bowel disease (IBD), and irritability. It is thought that it may cause diseases such as intestinal syndrome (IBS). , colorectal cancer. However, human intervention research on this topic is limited.

Research: Ultra-processed foods and food additives in gut health and disease. Image credit: Lightspring / Shutterstock

UPF identification

To classify a food as UPF, nutritionists must determine how the item differs from the original raw ingredients, how it is processed, whether additives are used, and whether it is commercially produced rather than homemade. Use criteria related to whether the product is manufactured or used for appearance or convenience. .

However, the different classification systems make comparisons difficult. The most common have been adopted by the Food and Agriculture Organization of the United Nations and include powdered and packaged foods, carbonated soft drinks, and sweetened breakfast cereals as UPF. However, some foods, such as whole-grain breads and plant-based alternatives to meat, are widely considered healthy but still meet UPF standards.

UPF consumption and gut health

Although UPF is prevalent, there is great variation between individuals and countries. In the United States, UPF consumption accounts for 59.7% and 67% of the energy intake of U.S. adults and youth, respectively.

Individual characteristics associated with increased UPF intake include being female, younger, lower income, lower education, living alone, overweight or obesity, lower physical activity, and use of screens at mealtimes.

People who consume more UPF have more free sugars, saturated fat, and energy in their diets, but less fiber, protein, and many micronutrients. Vegetarians and vegans are more likely to get his UPF, while those who follow a Mediterranean diet get less.

By controlling diet quality and nutrient intake, there is evidence of an association between UPF intake and disease. However, his UPF intake from fruit yogurt, fortified breakfast cereals, and whole grain breads is healthier than his UPF intake at the same level from prepared meals, hamburgers, and pastries.

Cohort studies have found that UPF intake is associated with increased mortality and morbidity from cancer, cardiovascular disease, and type 2 diabetes. Observational studies have shown an association with depression, metabolic syndrome, overweight, and obesity. These effects are likely due to the processing rather than the nutrient or energy content of the UPF.

Furthermore, a cohort study examining UPF intake and IBD (ulcerative colitis and Crohn's disease) found that those with high UPF intake faced the highest risk. Similar results were obtained by examining only Crohn's disease, but not ulcerative colitis. A cohort study found significant associations between UPF intake and IBS and functional dyspepsia, but not functional diarrhea or constipation. UPF intake has also been linked to distal colon cancer and colorectal adenomas in men.

Methodological inconsistencies, including the use of self-reported dietary data, may bias results and limit comparisons between studies and the use of meta-analytic techniques. The negative health effects associated with UPF may be caused by its effects on the gut microbiome, but only two of his studies have investigated this.

Effects of food additives

Food additives include sweeteners, colorants, stabilizers, emulsifiers, thickeners, and gelling agents. There is considerable overlap between UPF and food additives, as items containing commercially available food additives are considered UPF. Mechanistic studies on the effects of food additives on the microbiome include animal and in vitro studies, with few studies in human populations.

in vitro Studies have shown that emulsifiers such as polysorbate 80 can cause small intestinal bacterial overgrowth, and carboxymethylcellulose (CMC) can mobilize bacteria across the epithelium in vitro. This can lead to chronic inflammatory diseases and has been demonstrated in mouse studies. CMC and polysorbate 80 intake was also associated with tumor development and anxiety-like behavior in mice.

Artificial sweeteners pass through the gastrointestinal tract but are not digested and come into direct contact with the gut microbiome, which has not been well studied in humans. but, in vitro Animal studies also suggest that sweeteners such as aspartame, sucralose, and saccharin can alter the microbiome, disrupt intestinal permeability, shorten colon length, and increase mortality. I am.

However, these were short-term studies using doses much higher than those used in humans. Observational studies in humans found no differences in microbiota intake after 4 days of sweetener consumption, but background diet and dose-response relationships were not controlled.

In a randomized controlled trial, constipation, diarrhea, burning sensation, and postprandial discomfort increased after 5 weeks of sweetener intake, while epigastric pain, early satiety, and abdominal pain decreased in a control group on a sweetener-restricted diet. It turned out that it did.

conclusion

Although there are clear indications that UPF and food additives pose adverse health effects, methodological inconsistencies and gaps in human trials need to be addressed. The authors emphasize the need for high-quality evidence to interpret the effects of dietary interventions. As UPF availability and consumption increases, public health policy must target UPF reformulation and consumer behavior.