This study was published online on July 27, 2022, in Neurology, the official journal of the American Academy of Neurology.
According to a new study, those who consume the most ultra-processed foods, such as cookies, chips, and soft drinks, may have a higher risk of developing dementia than those who consume the least of these foods. Researchers also discovered that a lower risk was connected with replacing highly processed foods in a person’s diet with unprocessed or less processed items.
The research did not establish a causal link between ultra-processed meals and dementia. Only an association is displayed.
Foods that have undergone extreme processing are poor in protein and fibre and rich in added sugar, fat, and salt. Soft beverages, salty and sweet snacks, ice cream, sausage, deep-fried chicken, yoghurt, canned tomatoes and baked beans, ketchup, mayonnaise, packaged guacamole and hummus, packaged bread, and flavoured cereals are some of the items on the list.
“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, Ph.D., 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, but it also found replacing them with healthy options may decrease dementia risk.”
From the UK Biobank, the research assessed 72,083 individuals. The study’s participants were 55 years of age or older and did not have dementia at the outset. They had an average of 10 years of follow-up. The study’s conclusion revealed that 518 participants had dementia.
Participants in the study completed at least two questionnaires on their eating and drinking habits the day before. By measuring the grammes per day and comparing them to the grammes per day of other foods to produce a percentage of the daily diet, researchers were able to calculate how much ultra-processed food people consumed. The subjects were then placed into four equal groups, ranging in ultra-processed food consumption percentage from the lowest to the greatest.
In the lowest category, hyper processed foods made up 9% of daily diets, or 225 grammes on average, while they made up 28% of diets, or 814 grammes on average, for those in the highest group. 150 grammes constituted one serving of foods like pizza or fish sticks. Drinks were the leading food category that contributed to a high intake of ultra-processed foods, followed by sweet foods and ultra-processed dairy. 105 of the 18,021 individuals in the lowest group acquired dementia, as opposed to 150 of the 18,021 individuals in the highest group.
Researchers discovered that for every 10% increase in daily consumption of ultra-processed foods, participants had a 25% increased risk of dementia after controlling for age, sex, family history of dementia and heart disease, among other variables that potentially affect the risk of dementia. Researchers also calculated the effects of replacing 10% of ultra-processed meals with unprocessed or minimally processed foods, such as fresh fruit, vegetables, legumes, milk, and meat, using study data. They discovered that such a change was linked to a 19% decreased incidence 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% 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.”
Maura E. Walker, Ph.D., of Boston University in Massachusetts, who wrote an editorial accompanying the study, said, “While nutrition research has started to focus on food processing, the challenge is categorizing such foods as unprocessed, minimally processed, processed, and ultra-processed. For example, foods like soup would be classified differently if canned versus homemade. Plus, the level of processing is not always aligned with diet quality. Plant-based burgers that qualify as high quality may also be ultra-processed. As we aim to understand better the complexities of dietary intake, we must also consider that more high-quality dietary assessments may be required.”
A limitation of the study was that cases of dementia were determined by looking at hospital records and death registries rather than primary care data, so milder cases may have been overlooked.
Li noted that further research is needed to confirm the findings.