Researchers find ultra-processed foods linked to hidden brain damage in Canadian study
Middle-aged Canadians eating high levels of ultra-processed foods were 40% more likely to show signs of vascular brain injury on MRI scans, though memory and thinking skills remained unaffected.
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A study of 8,783 Canadian adults has found that higher intake of ultra-processed foods is associated with greater likelihood of vascular brain injury — small areas of tissue damage linked to interrupted blood flow — detectable on MRI scans, even without obvious stroke symptoms.
The research, published in the Journal of the American Medical Association and conducted by McMaster University researchers including associate professor Russell de Souza and professor Sonia Anand, examined middle-aged Canadians aged 35 to 69 who had no cardiovascular disease at baseline. Those consuming the most ultra-processed foods were 40% more likely to show signs of what are known as silent strokes — brain changes that occur without obvious symptoms like slurred speech or arm paralysis, but carry elevated risk of future stroke and cognitive decline.
Participants in the highest ultra-processed food intake group also had higher levels of body fat (1.7 percentage points higher) and visceral fat — fat buried deep in the abdomen — (5.7 millilitres higher) compared to the lowest intake group. "In a group of middle-aged Canadians, those who ate more ultra-processed foods tended to have higher levels of body fat, higher levels of visceral fat, and a greater likelihood of having signs of vascular brain injury or silent strokes that were detected on MRI scans," de Souza said.
Anand emphasized the significance of detecting these brain changes without symptoms. "Essentially, when you put an MRI scan up and you look at the findings, we are seeing the same type of findings we would in someone who had a stroke with the symptoms of a stroke, such as slurred speech or paralysis of an arm or leg. So we're seeing those changes, even though participants didn't report stroke-like symptoms."
Ultra-processed foods, as defined by de Souza, are industrially formulated products containing ingredients, additives or processing methods not typically used in cooking at home — such as packaged snack foods, sugary breakfast cereals, soft drinks, ready-to-eat frozen meals, and fruit snacks or apple gummies. By contrast, minimally processed foods like an apple stand apart from processed items like applesauce with added sugar.
The study examined diet and health at a single point in time, which is a limitation researchers noted. Cognitive performance on memory, attention and thinking tests showed no difference by ultra-processed food intake level, suggesting the brain changes detected on MRI may precede measurable cognitive symptoms.
The facts
How many Canadian adults were involved in this study?
The study examined 8,783 Canadian adults aged 35 to 69 with no cardiovascular disease at baseline.
What percentage more likely were high ultra-processed food consumers to show vascular brain injury?
Those consuming the most ultra-processed foods were 40% more likely to show signs of vascular brain injury on MRI scans compared to the lowest intake group.
Who conducted this research?
McMaster University researchers including associate professor Russell de Souza and professor Sonia Anand conducted the study, which was published in the Journal of the American Medical Association.
What examples of ultra-processed foods were included in the study?
Ultra-processed foods studied included packaged snack foods, sugary breakfast cereals, soft drinks, ready-to-eat frozen meals, and fruit snacks or apple gummies — industrially formulated products containing ingredients, additives or processing methods not typically used in home cooking.
