Diets high in ultraprocessed foods raise dementia risk: study

Is your diet making you dimmer?

Foods like chips, cookies, frozen meals and sodas contribute to cognitive decline, according to a new study with data from more than 72,000 individuals.

Compared to whole food dieters, those who consume high amounts of ultraprocessed dishes appear more likely to develop dementia. And for every 10% increase in junk food consumption, researchers saw a 25% spike in the likelihood of being diagnosed with the neurodegenerative disease.

The cause for this correlation is not yet clear, but scientists for the American Academy of Neurology have said that previous studies support the connection between what we put in our bodies and how it affects the mind.

Ultraprocessed foods are defined by their high percentages of sugar, fat and salt, as well as a dearth of protein and fiber.

And they can be misleading, researchers point out, as even seemingly healthful foods — such as prepackaged (not homemade) guacamole or low-calorie frozen meals — are often laden with dubious ingredients, additives and preservatives.

“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, PhD, of China’s Tianjin Medical University, in a statement. “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,” Li added.

Researchers pulled from the UK Biobank, a medical database of some half a million UK residents, for their analysis, and identified 72,083 viable participants aged 55 and older with no prior history of dementia. The cohort was then divided into four groups, on a scale lowest to highest based on the percentage of ultraprocessed foods they ate each day.

Ultraprocessed foods accounted for 9% of the average daily diet of those on the lowest tier of junk food intake. On the other end of the spectrum, ultraprocessed foods made up about 28% of what people ate everyday.

By the end of the UK Biobank survey, which followed participants for an average of 10 years, 518 of those included in the current report had developed dementia — 150 of whom were included in the group with the highest junk food intake.

After accounting for dementia’s high risk factors, such as age, gender and family medical history, researchers found a 25% higher risk of dementia for every 10% jump in ultra-processed foods consumption. Conversely, those who reduced their junk food intake by 10% benefited from a 19% lower risk of developing dementia.

The most common junk food among all participants was sugary drinks, followed by sweets and ultraprocessed dairy, such as American cheese.

Small substitutions in diet can translate into big health gains, Li noted — though the habit can be difficult to kick as researchers have previously speculated about the addictive qualities in junk food.

“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.”