Eating large amounts of ultra-processed foods, including packaged snacks, sugary breakfast cereals, soft drinks, instant noodles and ready-to-eat meals, may be associated with early signs of brain damage linked to an increased risk of stroke and future memory problems, according to a study published in JAMA Network Open.
Researchers used magnetic resonance imaging (MRI) scans to examine the brains of nearly 9,000 people. They found tiny areas of brain damage more frequently among participants who consumed the highest amounts of ultra-processed foods than among those who ate the least.
Participants with the highest intake were approximately 40% more likely to show these changes. Although these abnormalities do not cause obvious symptoms, they may serve as early warning signs of potential brain health problems.
Russell J. de Souza, the study’s first author and an associate scientist at the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences, said the findings were unexpected because the researchers studied middle-aged Canadians who had no history of heart disease or other reported health concerns. He noted that this type of brain damage is generally associated with health conditions that become more common in older age.
Study Finds Stronger Association Among Women
The PHRI-led study included Canadians aged 35 to 69 who had no history of heart disease and lived in communities across Canada. Researchers observed a stronger association between ultra-processed food consumption and brain abnormalities among women. Women in the highest consumption group were nearly twice as likely to show signs of brain damage as those in the lowest consumption group.
Participants who consumed the most ultra-processed foods also had higher levels of body fat and deep abdominal fat. This type of fat is associated with inflammation and blood vessel damage, which may affect brain health. Sonia Anand, the study’s senior author and a senior scientist at PHRI, said the findings suggest that links between dietary habits and brain health may become detectable before people experience noticeable problems with memory or thinking. She added that food choices during the 30s, 40s, 50s and 60s may influence brain health later in life.
Ultra-Processed Foods Raise Nutritional Concerns
Researchers classified foods according to the extent and purpose of industrial processing involved in their production. Many ultra-processed foods contain high levels of sodium, added sugars and saturated fats while providing relatively little fibre, vitamins and minerals. Moreover, their convenience, affordability, widespread availability and intensive marketing can encourage frequent consumption. These factors may particularly affect people with limited time or financial resources, potentially widening existing health inequalities. According to Anand, although ultra-processed foods offer convenient and affordable options, diets containing large amounts of these products may be associated with brain changes that could affect memory and stroke risk as people age.
Ultra-Processed Foods May Displace Healthier Choices
The study found that ultra-processed foods accounted for approximately 25% of daily food servings among participants on average. Among the heaviest consumers, they represented 45% of daily servings, compared with just 16% among those who ate the least. At the same time, consumption of whole and minimally processed foods declined as ultra-processed food intake increased. Fruits, vegetables, grains and other minimally processed foods accounted for 41% of daily servings among participants with the highest ultra-processed food consumption. In contrast, these healthier food choices represented 68% of daily servings among those with the lowest consumption. De Souza explained that people who consumed more ultra-processed foods were not simply adding these products to their usual diets. Instead, these foods appeared to replace healthier whole-food options. The findings highlight the importance of maintaining a balanced diet that includes fruits, vegetables, whole grains and other nutrient-rich foods.
Researchers Call for Long-Term Studies
To investigate the relationship between diet and brain health, researchers analysed data from two PHRI studies: the Canadian Alliance for Healthy Hearts and Minds and the Prospective Urban and Rural Epidemiology-MIND study. Participants completed detailed dietary questionnaires and underwent MRI brain scans. Neurologists reviewed the scans without knowing the participants’ dietary habits, helping reduce potential assessment bias.
However, the researchers assessed participants at a single point in time and did not track changes in their brains over an extended period. Therefore, the study establishes an association rather than proving that ultra-processed foods directly cause brain damage. The researchers emphasised the need for longer-term studies involving repeated MRI scans to determine whether reducing ultra-processed food consumption can slow or prevent these changes. De Souza said follow-up research is ongoing to investigate how dietary changes may influence brain health over time.
Balanced Eating May Support Long-Term Brain Health
The findings add to research examining how dietary patterns may influence brain health and the risk of age-related neurological problems. However, further studies are necessary to establish whether ultra-processed food consumption directly contributes to silent brain damage. In the meantime, limiting ultra-processed foods and choosing a greater variety of minimally processed, nutrient-rich foods can help support overall health. As reported by Medical Express, researchers say long-term follow-up will be essential to understand whether these dietary changes can reduce the risk of stroke and memory problems.