August 24, 2022
People who regularly eat a lot of highly processed foods and drinks like cheeseburgers, chips, fried chicken, sausage, pizza, biscuits and sugary sodas are at increased risk of developing dementia, according to a new report. The study found that for every 10 percent increase in daily intake of highly processed foods, the risk of dementia increased by 25 percent. Substituting whole or minimally processed foods for highly processed foods, the study found, led to a lower dementia risk.
The findings add to growing evidence that what we eat can affect our brain health. Eating highly processed fast foods and other junk foods, numerous studies suggest, increases the chances of developing Alzheimer’s disease, the most common form of dementia overall. Eating a protein-rich, high fiber diet containing lean meats, seafood (not fried), whole fruits and vegetables, and heart-healthy fats like olive oil, on the other hand, may lower dementia risk.
The current study looked at ultra-processed foods, which account for more than half of the calories that Americans consume. They include most fast foods, sodas and packaged goods and are typically high in added sugars, refined carbohydrates, salt and fats, as well as synthetic flavoring agents and preservatives. Examples of highly processed foods include many popular brands of packaged breads and crackers, soft drinks, breakfast cereals, sweetened yogurts, snack bars, ice cream, ketchup, mayonnaise and canned baked beans. “Low-fat” chips and snacks may be lower in oils but are typically still highly processed.
“Ultra-processed foods are meant to be convenient and tasty, but they diminish the quality of a person’s diet,” said study author Huiping Li, of Tianjin Medical University in China. “These foods may also contain food additives or molecules from packaging or produced during heating, all of which have been shown in other studies to have negative effects on thinking and memory skills. Our research not only found that ultra-processed foods are associated with an increased risk of dementia, it found replacing them with healthy options may decrease dementia risk.”
For the study, published in Neurology, researchers looked at 72,083 men and women who were part of the UK Biobank, a large medical database of people living in Britain. Participants were 55 or older at the study’s start, and none had Alzheimer’s disease or other forms dementia. Participants also completed detailed questionnaires about what they ate and drank in a typical day, with a focus on their intake of ultra-processed foods.
The researchers tracked them for an average of 10 years, and during that time, 518 were diagnosed with dementia, including 287 with Alzheimer’s disease. The study found that those who ate the most highly processed foods — accounting for more than a quarter of their daily diets, or an average of 814 grams a day — were at highest risk of developing dementia. Those who ate the least amount of highly processed foods — less than 10 percent of their daily food intake, or about 225 grams a day — had the lowest risk. The researchers calculated that substituting 10 percent of ultra-processed foods with healthier alternatives like fresh fruits and vegetables, meats, nuts or milk was associated with a 19 percent lower risk of dementia.
“Our results also show increasing unprocessed or minimally processed foods by only 50 grams a day, which is equivalent to half an apple, a serving of corn, or a bowl of bran cereal, and simultaneously decreasing ultra-processed foods by 50 grams a day, equivalent to a chocolate bar or a serving of fish sticks, is associated with 3 percent decreased risk of dementia,” said Li. “It’s encouraging to know that small and manageable changes in diet may make a difference in a person’s risk of dementia.”
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Huiping Li, Shu Li, Hongxi Yang, Yuan Zhang, et al: “Association of Ultraprocessed Food Consumption With Risk of Dementia: A Prospective Cohort.” Neurology, July 27, 2022