Children who consume more ultra-processed foods may show a stronger response in the brain’s reward system when viewing appealing foods, according to research published in JAMA Network Open. In a study of 46 children, greater activity in the dorsal striatum was associated with higher ultra-processed food intake and with larger increases in body mass index (BMI) and body fat over the following year. The observational findings suggest that heightened sensitivity to food cues may help explain the association between ultra-processed diets and later changes in body composition, although they do not establish that these foods directly cause changes in brain activity or weight.
Ultra-processed foods include many everyday products, such as breakfast cereals, packaged breads and instant soups. They are often designed to be attractive and convenient and to remain fresh for long periods. Many contain artificial sweeteners, colors and other ingredients that are 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. Scientists are still working to understand the biological processes that might 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 investigate whether children’s brain responses to food could 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 scans reveal a link with future 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 the participants had a healthy weight at the start of the study, allowing researchers to investigate possible warning signs before excess weight developed.
At the beginning of the study, the children underwent brain scans while viewing pictures of appealing foods, such as cookies and French fries. Researchers also collected information about their diets and recorded several health measures, including BMI, body fat percentage and waist circumference. The team measured these physical characteristics again one year later.
The scans showed that children who consumed more ultra-processed foods had greater activity in the dorsal striatum when viewing food images. This brain region helps regulate reward and motivation and is involved in responses to desirable foods.
Children with stronger responses in the dorsal striatum also tended to have larger increases in BMI and body fat percentage over the following year. The findings suggest that heightened sensitivity to food cues may be one factor connecting ultra-processed food consumption with subsequent weight gain.
How reward activity may be related to body fat
By the end of the study, children who consumed 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 explain these associations. After the analysis was adjusted 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.”
Making healthier food more accessible
The researchers said that improving children’s eating habits cannot depend entirely on individual families. Ultra-processed products are often inexpensive, widely available and easy to prepare, making them practical options 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 consuming ultra-processed foods directly causes increased brain activity or weight gain. Although the research establishes relationships among these factors, additional studies are 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. Researchers 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 Study will continue tracking participants as they move through adolescence and into early adulthood. By monitoring brain development, body composition, dietary patterns and overall health over time, researchers hope to gain a clearer understanding of 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, as well as 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 and 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