Middle-aged adults who eat large amounts of ultra-processed foods carry more body fat and visceral fat and are more likely to show signs of silent damage to the brain's blood vessels, a new study found. Cognitive tests, however, showed no significant link to how much ultra-processed food participants ate. With such foods accounting for a substantial share of what Koreans eat, researchers say consumption warrants caution. The Korea National Health and Nutrition Examination Survey estimates that ultra-processed foods make up about 25% of energy intake in South Korea.
The findings, by a team at the Population Health Research Institute of McMaster University in Canada, were published recently in the international journal JAMA Network Open. The researchers analyzed dietary questionnaires, body fat measurements, brain MRI scans and cognitive test results from 8,783 adults aged 35 to 69 with no history of cardiovascular disease.
Ultra-processed foods are products made through industrial processing. Packaged snacks, sweetened cereals, soft drinks, instant noodles and frozen ready meals are among the most common examples. These foods tend to be high in sodium, added sugar and saturated fat while containing relatively little dietary fiber and, in some cases, fewer nutrients.
The group that consumed the most ultra-processed food had a body fat percentage 1.7 percentage points higher than the group that consumed the least, and an average of 5.7 milliliters more visceral fat by volume. No statistically significant difference emerged in liver fat percentage.
The likelihood of vascular brain damage — which the researchers defined as silent stroke, extensive white matter hyperintensities, or both — was 40% higher in the highest-consumption group than in the lowest. White matter hyperintensities are areas of the brain's white matter that appear bright on MRI scans and can indicate changes associated with cerebrovascular disease. Such damage can appear before any clinical decline in cognitive function is detected.
Cognitive function, assessed through the Montreal Cognitive Assessment (MoCA), which evaluates memory, attention and language ability, and the Digit Symbol Substitution Test (DSST), which measures attention, working memory and psychomotor speed, showed no significant association with ultra-processed food intake.
"Ultra-processed foods are often a convenient and inexpensive option," the research team said, adding that the study suggests a diet heavy in such foods may be linked to brain changes that can lead to memory loss and stroke with age. The researchers cautioned that because the study was cross-sectional, comparing diet and health status at a single point in time, it cannot determine whether ultra-processed foods directly caused the damage to brain blood vessels. Long-term follow-up research is needed to establish whether these changes lead to later cognitive decline, they said.
