A new study from Harvard’s T.H. Chan School of Public Health has found that consuming over two pounds of ultraprocessed foods daily is associated with a 58% increased risk of developing dementia and a 46% higher risk of cognitive impairment. The research, which analysed data from more than 5,300 older adults over nearly a decade, highlights the potential dangers of foods such as hot dogs, cookies, and other highly processed items.
Ultraprocessed foods now make up around 70% of the American diet, according to the National Institute of Health, as manufacturers have enhanced flavour, colour, and shelf life. These products are designed to be “hyperpalatable” with combinations of salts, fats, and sugars. Previous studies have linked such foods to negative impacts on brain health, heart health, and the immune system.
The Harvard study found that even moderate consumption—around one pound per day—was associated with increased risk. “Just to say, ‘well, I don’t eat all my calories from ultraprocessed foods, I’m safe.’ It really shows there may not be a safe level,” said Cindy Leung, an associate professor of public health nutrition, commenting on the findings.
Processed meats, such as bacon and sliced ham, were linked to the highest risk of dementia and cognitive impairment. However, the researchers caution that because the data is self-reported, they cannot prove causation. Nonetheless, ultraprocessed foods are also tied to known risk factors for dementia, including obesity, gut changes, and cardiovascular disease.
In contrast, the study found that people who ate the most minimally processed foods, such as fruits and vegetables, had a 41% lower risk of dementia. Experts recommend moderation and balanced dietary choices to reduce risk. “There are things that you can change,” said Brenda Davy, a professor of human nutrition, foods, and exercise.
