Children who consume more ultra-processed foods may show a stronger brain response to appealing foods, a pattern that could help explain why these products are associated with weight gain. In a study published in JAMA Network Open, children who ate more ultra-processed foods had greater activity in the brain’s reward system while viewing pictures of appetizing foods. Stronger responses were also associated with larger increases in body fat over the following year.
Ultra-processed foods include many everyday products, such as breakfast cereals, packaged breads and instant soups. They are convenient, attractive and manufactured to remain fresh for long periods. Many contain artificial sweeteners, colors and other ingredients rarely used in home cooking. These products account for approximately 67% of the calories consumed by children in the United States.
Previous research has linked ultra-processed food consumption with obesity, type 2 diabetes and cardiovascular disease. However, scientists are still investigating the biological processes that may explain these relationships. Supported in part by the National Institutes of Health, the new study combined magnetic resonance imaging (MRI), dietary assessments and body-composition measurements to examine whether children’s brain responses to food might play a role.
“Children’s brains are still developing, habits are forming, and food preferences are forming. This is a critical period when the brain is highly sensitive to food and food environments,” said study lead author Kathleen A. Page, M.D., Ph.D., co-chair of the Division of Endocrinology and Diabetes and professor of medicine and pediatrics at the Keck School of Medicine of Southern California. “We are particularly interested in understanding these processes in children because we believe that early intervention can make a big difference.”
Brain activity was linked to later weight gain
The research team studied 46 children aged 7 to 10 who were enrolled in the ongoing Brain Child Study, which examines factors related to diabetes and obesity. All participants had a healthy weight at the beginning of the study, allowing the researchers to look for potential warning signs before excess weight developed.
At the start of the study, the children underwent brain scans while viewing pictures of appealing foods, such as cookies and French fries. The researchers also gathered dietary information and recorded health measurements, including body mass index (BMI), body-fat percentage and waist circumference. These physical characteristics were measured again one year later.
The scans showed that children who consumed more ultra-processed foods had greater activity in the dorsal striatum when they viewed food images. This region helps regulate reward and motivation and is involved in responses to desirable foods.
Children with stronger responses in the dorsal striatum tended to have larger increases in BMI and body-fat percentage during the following year. The finding suggests that heightened sensitivity to food cues may be one factor connecting ultra-processed diets with subsequent weight gain.
The brain’s reward response may help explain the association
By the end of the study, children who ate more ultra-processed foods generally had higher BMIs, higher body-fat percentages and larger waist circumferences.
The researchers then examined whether differences in brain activity could help account for these associations. After adjusting the analysis for the children’s dorsal-striatum responses, the association between ultra-processed food intake and BMI was 31% weaker. The association with body-fat percentage decreased by 44%.
These reductions suggest that the brain’s reward response may account for part of the relationship between ultra-processed food consumption and changes in body composition. The results do not prove that these foods directly alter brain function, but they point to a possible biological explanation for associations reported in earlier studies.
“This study goes beyond understanding that UPF affects weight gain,” Page said. “This actually gives us insight into the neurobiological basis by which these foods may be associated with body composition over time.”
Researchers call for healthier food access
Improving children’s diets cannot depend entirely on individual families, the researchers cautioned. Ultra-processed products are often inexpensive, widely available and easy to prepare, making them a practical option for households facing financial or time constraints.
“Changing the food environment so people have access to healthier, minimally processed foods is an important part of the solution,” Page said.
The study has important limitations. Because it was observational, it cannot determine whether eating ultra-processed foods directly causes increased brain activity or weight gain. Although the findings establish a relationship between these factors, additional research is needed to determine whether one causes another.
Page hopes to address that question in future intervention studies. The proposed research would provide children who regularly consume ultra-processed foods with a more minimally processed alternative. Scientists could then examine whether dietary changes affect the brain’s response to food images and whether any differences are associated with reduced weight gain.
The Brain Child research is also continuing to track participants as they move through adolescence and into early adulthood. By monitoring brain development, body composition, dietary patterns and general health over time, researchers hope to clarify how childhood nutrition affects long-term health.
Research team and funding
The study was led by Page, along with Jasmine M. Alves, Ella Morgan, Brendan Angelo, Kiana Lu and Jared Smith from the University of Southern California School of Medicine’s Division of Endocrinology and Diabetes and the Diabetes and Obesity Research Institute. Additional contributors included Kay Jann of the USC Stevens Neuroimaging and Informatics Institute at the Keck School of Medicine of the University of Southern California, and Ting Chow and Anny H. Xiang of the Division of Research and Evaluation at Kaiser Permanente Southern California in Pasadena, California.
Funding came from an American Diabetes Association Pathway Accelerator Award [1-14-ACE-36] and the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (NIH) [R01DK116858, R01DK134079]. Support for the REDCap database used in the study was provided by the Southern California Institute for Clinical and Translational Sciences [NIH UL1TR001855].
Source: www.sciencedaily.com
