In a recent study published in BMC Medicine, researchers investigated the association between ultra-processed food (UPF) intake, obesity, and metabolic indicators in preschool children in Chile.

Study: Consumption of highly processed foods was associated with obesity but not with metabolic indicators in a prospective cohort study of Chilean preschool childrenPhoto credit: Rimma Bondarenko/Shutterstock.com

background

Childhood obesity has become a growing health problem worldwide. Childhood obesity persists over a longer period of time and is related to metabolic disorders that appear at a younger age. UPF intake is associated with health disorders such as obesity, especially in adults.

However, research on metabolic effects in children is limited and inconsistent. Given the health costs of inadequate nutrition in children and the exponential increase in UPF consumption, it is critical to understand the impact on metabolic risk variables.

About the study

In the present prospective cohort study, researchers investigated the impact of UPF on obesity and metabolic outcomes in preschool children in Chile after 2 years.

The researchers analyzed data from 962 pediatric participants in the Food and Environment Chilean Cohort (FECHIC) study. They collected dietary data from four-year-olds in 2016 using 24-hour recall data. The recall data were collected using the U.S. Department of Agriculture (USDA) multiple-run technique.

The team excluded records with extreme UPF consumption. The main respondents were mothers who reported on their children’s food intake in a day in face-to-face interviews. Children participated in the interviews and provided additional information about meal times in the absence of the respondents (e.g. during school hours).

The researchers used the NOVA classification to categorize foods and the Multiple Source Method (MSM) to estimate the consumption of ultra-processed foods in grams and calories.

The first group consisted of natural and minimally processed foods, the second group of processed kitchen ingredients, the third group of processed foods, and the fourth group of UPF.

The team measured obesity and metabolic indicators at age six in 2018. Obesity indicators included waist circumference, fat mass in percent and kilograms, and body mass index (BMI) z-scores.

Metabolic indicators included insulin, fasting blood glucose, homeostatic model assessment of insulin resistance (HOMA-IR), low-density cholesterol (LDL-c), high-density cholesterol (HDL-c), triglycerides, and total cholesterol.

The researchers estimated energy requirements using the recommended intake (DRI) equation. Linear regressions adjusted for covariates and total caloric intake determined the relationship between UPF intake and study outcomes.

Regressions included inverse probability weighting that accounted for loss to follow-up. Study covariates included age, sex, BM z-Outcomes, children’s television time, and maternal factors such as BMI, age, education, work outside the home, and socioeconomic status.

Directed acyclic graphs (DAGs) represented causal networks linking exposure and study outcomes. Disagreements regarding food categorization were resolved by consensus among the team, and a third dietitian independently categorized a subset of the data to confirm inter-rater agreement.

Results and discussion

At the start of the FECHIC study, the mean age of the children was five years, 52% were female, and the mean BMI z-score was 1.0. The mothers were 31 years old, and 55% had a secondary level of education.

After two years, mean fat mass was 24% and mean fasting blood glucose was 82 mg/dl.

Regular UPF intake accounted for 48% of caloric intake and 39.0% of total food intake in grams at age 4. UPF accounted for the largest share of calories in the children’s diets, while minimally processed foods contributed the largest share (57%).

The fitted models showed positive associations between UPF intake and BMI, waist circumference, logarithm of body fat mass, and logarithm of percent fat, but no relationship with metabolic markers.

Sensitivity analyses using models without the stabilized inverse probability of censoring weights and considering UPF uptake in quartiles yielded similar results.

The proportional contribution of UPF to the diet is more significant than the total amount, and the reported health improvements are the result of a shift away from traditional dietary habits.

UPFs are associated with adverse health effects because they have a poor nutritional profile, high levels of added sugar and saturated fat, and low levels of vitamins and minerals.

Refined ingredients are often used in the production of UPF, resulting in a lower feeling of satiety and an increased glycemic response. UPF also have a high energy density and low water content, so they can be consumed quickly in terms of volume and calories, encouraging overconsumption.

Their reduced protein density may lead them to overeat other foods. Widespread UPF consumption may also increase the intake of rare or non-existent chemicals such as food additives.

Diploma

The results of the study showed that UPF consumption was associated with obesity in Chilean preschool children after two years, but had no metabolic consequences. Longer follow-up studies may help to understand the history of ultra-processed food consumption and the associated dangers.

Health authorities and policy makers should strengthen their global actions to create an environment that promotes diets with minimally processed foods while limiting children’s access to UPF meals.