A new study suggests that diets high in ultra-processed foods –– including American favorites such as pizza, french fries, and hot dogs –– can increase the risk of developing cognitive illnesses like dementia. Researchers found that if 20 percent or more of your daily calorie intake is ultra-processed foods, your risk of cognitive illness is significantly higher, according to the study, which was published in JAMA Neurology. 

The study defines ultra-processed foods as food containing large amounts of oils, fats, sugars, starches, and protein isolates, among additional artificial flavors, colorings, and emulsifiers. The research team analyzed dietary and cognitive data from 10,775 participants between the ages of 35 and 74 in six Brazilian cities: Vitoria, Sao Paulo, Rio de Janeiro, Porto Alegre, Belo Horizonte, and Salvador.

“In Brazil, ultra-processed foods make up 25 percent to 30 percent of total calorie intake. We have McDonald’s and Burger King, and we eat a lot of chocolate and white bread. It’s not very different, unfortunately, from many other Western countries,” Dr. Claudia Suemoto, co-author and an assistant professor in the division of geriatrics at the University of São Paulo Medical School, said to CNN after the study abstract was released this August.

“Fifty-eight percent of the calories consumed by United States citizens, 56.8 percent of the calories consumed by British citizens, and 48 percent of the calories consumed by Canadians come from ultra-processed foods."

The study examined how diets that contain ultra-processed foods can lead to higher rates of cognitive illness, finding that a diet consisting of 19.9 percent ultra-processed foods led to a 28 percent faster rate of cognitive decline.

Brain Health and Diet

To conduct the study, the researchers examined the participants three times between 2008 and 2017, recording their dietary changes and analyzing their cognitive ability. The participants' diets were gauged in comparison to the MIND diet –– a combination of the DASH diet designed to improve brain health with increased plant-based whole foods and the Mediterranean diet. Foods were classified into four groups depending on their manufacturing process.

The researchers required the participants to complete recognition tests, semantic and fluency assessments, and other memory examinations to gauge cognitive aptitude. The study also found that among the increased mental decline rates, individuals consuming more ultra-processed foods experienced a 25 percent increased rate of executive function decline. In contrast, no substantial memory function decline was recorded.

“A higher percentage of daily energy consumption of ultra-processed foods was associated with cognitive decline among adults from an ethnically diverse sample,” the study concluded. “These findings support current public health recommendations on limiting ultra-processed food consumption because of their potential harm to cognitive function.”

Researchers proposed that the cognitive decline could be attributed to cerebrovascular lesions and inflammation in the brain caused by consistent ultra-processed food consumption. However, more research is needed to fully understand the internal cause. The study also noted that participants under 60 were more likely to experience cognitive decline than individuals above 60 years old.

Eat Healthy for Your Brain

This July, another study claims that eating high amounts of ultra-processed foods is associated with higher dementia risk. Researchers analyzed the dietary patterns of 72,000 individuals aged 55 or older to examine how processed foods correlated with dementia development over approximately 10 years. The research revealed that for a 10 percent increase in daily ultra-processed foods consumption, participants experienced a 25 percent higher risk of dementia.

In June, one study found that vegetarians and pescatarians have better memories than meat eaters, concluding that meat consumption is worse for short-term memory function. This research is accompanied by another study that found that a Mediterranean diet helps improve brain health, highlighting how reduced processed food consumption is associated with better brain functioning.

Beyond cognitive decline, a plant-based diet also helps improve mental illnesses such as depression. Some research suggests that increased mushroom consumption can lead to a reduced risk of depression.

Processed Foods and Health Risks

Eating processed foods –– especially processed meat –– leads to several health risks including cancer, heart disease, and more. Eating red and processed meats increases the risk of heart disease by up to 18 percent. But cutting out processed foods and meat can be difficult, and that's because the brain becomes addicted to fatty foods.

This September, a study revealed that bacteria begin to crave more high-fat foods the more you eat them. To curb this addition, adding more plant-based foods to replace processed foods can reduce this craving and keep your brain and body healthier.

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