Study identifies metabolic changes caused by highly processed foods, raising concerns about their role in obesity, cardiovascular disease and impaired gut health.
Study: Association of Highly Processed Food Intake with Non-Target Metabolic Profiles in Adolescents and Young Adults in the DONALD Cohort Study. Image credit: Rimma Bondarenko / Shutterstock
Scientists in France and Germany conducted a study to identify urinary and plasma metabolic biomarkers associated with highly processed food intake in adolescents and young adults.
The study is currently available as a pre-proof at The Journal of Nutrition.
Background
Ultra-processed foods refer to industrially processed foods that contain food-derived or reconstituted ingredients and other industrially isolated ingredients. These ingredients are commonly used to increase the shelf life and sensory properties of products.
The intake of highly processed foods is increasing exponentially worldwide, especially in developed countries. Epidemiological studies have consistently linked high intakes of highly processed foods, particularly animal products and sugary drinks, with increased risks of obesity, cardiovascular disease, and metabolic disorders. Excessive intake of highly processed foods is also associated with chronic kidney disease, cancer and neuropsychiatric complications.
Highly processed foods contain excessive amounts of added sugars, salts, saturated fat, energy-dense ingredients, and lower amounts of protein and dietary fiber. Such poor nutrient profiles are thought to be responsible for negative health consequences.
In this study, scientists determined associations between highly processed food intake in both plasma and urinary metabolite levels in adolescents and young adults. They applied untargeted metabolomic analysis to capture a wide range of metabolic changes associated with highly processed food intake.
The scientists chose these two biological matrices because short-term changes in metabolite levels associated with dietary intake are more reliably reflected in urine samples, and plasma samples provide a more stable overview of metabolic states that respond to diet over the long term.
Study design
The scientists analyzed data from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study, an ongoing study designed to routinely assess and follow healthy infants into adulthood.
The DONALD study has recruited healthy infants annually since 1985 and routinely assesses their dietary intake, anthropometric measurements, urine sample collection, blood sample collection, medical parameters, lifestyle factors, and other sociodemographic data.
Data from adolescents who provided 3-day dietary records and 24-hour urine samples were analyzed to determine the association between ultra-processed food intake and urinary metabolic profiling.
For young adults, the association between ultra-processed food intake and blood metabolic profile was determined by analysis of 3 or more 3-day dietary records within the 5-year period preceding a single blood measurement.
Important observations
A total of 339 adolescent urine samples and 195 young adult blood samples were analyzed in this study. There was an overlap of 139 participants between the two groups.
The percentages of ultra-processed food intake relative to total food intake in adolescents and young adults were 22% and 23%, respectively. The most commonly consumed ultra-processed foods in both groups were sugary drinks and ready-to-heat or ready-to-eat foods.
Sweets, chocolates, ice cream, cereals, industrial breads and processed meats and sausages contributed the most to energy intake.
Effect of ultra-processed food intake on urinary metabolic profile
A total of 42 highly processed food-responsive metabolites were identified in adolescent urine samples. Of these metabolites, 21 showed positive associations with highly processed food intake.
Among known metabolites identified in urine samples, intake of ultra-processed food showed a significant positive association with indoxyl glucuronide and other partially characterized glucuronides. These glucuronides are involved in detoxification processes, particularly in the elimination of dietary substances through glucuronidation pathways.
Effect of ultra-processed food intake on plasma metabolic profile
A total of six highly refined food-responsive metabolites were identified in young adult plasma samples. Of these metabolites, 4-hydroxyglutamate and two structurally unknown metabolites showed positive associations with highly processed food intake. 4-Hydroxyglutamate has previously been linked to metabolic syndrome and may be a marker of metabolic stress.
Effect of ultra-processed food intake on urine and plasma metabolite patterns
A total of 25 metabolite patterns, identified using robust sparse principal component analysis (PCA), explained 61.7% of the variance in hyperprocessed food-induced metabolic changes in adolescent urine samples. A significant positive association of ultra-processed food intake with a urinary metabolite pattern (“xenobiotics and amino acids”) and a plasma metabolite pattern (“lipids, xenobiotics and amino acids”) was observed.
Both metabolite patterns shared 29 metabolites mainly associated with xenobiotic metabolism, which involves the breakdown and elimination of foreign substances such as food additives.
Importance of study
The study finds that highly processed foods can cause changes in urinary and plasma metabolite levels in adolescents and young adults through several pathways, including xenobiotic metabolism, amino acid metabolism, and lipid pathways.
The study identifies indoxyl glucuronide and other partially characterized glucuronides as major urinary metabolites positively associated with ultra-processed food intake. Glucuronides are produced during glucuronidation, a key biological detoxification pathway.
Regarding diet-related glucuronidation, evidence suggests that the gut microbiome plays a key role in regulating the microbial transformation of dietary substrates and glucuronide levels and the biosynthesis of microbial metabolites.
It is also well documented in the literature that highly processed foods can cause gut microbiota dysbiosis, which in turn is associated with a range of health adversities, including immunological and neuropsychological disorders.
Overall, the study findings provide useful insights into the complex biological mechanisms through which highly processed foods can affect metabolism and health. The findings also raise concerns about how the shift to minimally processed foods from highly processed options can lead to both nutritional deficiencies and disruptions to gut health.
