Two unpublished studies presented at the 2022 Alzheimer's Association International Conference suggest that certain factors "can significantly accelerate cognitive decline" and increase an individual's risk of dementia.

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Ultra-processed foods may 'significantly accelerate cognitive decline'

In a study presented Monday at the conference, researchers at the University of Sao Paulo analyzed the diets of over 10,000 adults, with an average age of 50.6, and examined their cognitive abilities through standardized tests.

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According to the study, which has not been peer-reviewed, participants who got at least 20% of their daily calories from ultra-processed foods (UPFs) experienced a faster decline in cognitive abilities over six to 10 years compared with those who consumed fewer UPFs. These foods include items like white bread, cookies, crackers, fried foods, candy, and processed meats.

Claudia Suemoto, an author of the study and assistant professor of geriatrics at the University of Sao Paulo Medical School, and her team found that participants who consumed the most UPFs experienced a 25% faster decline in their "executive function," or ability to plan and execute an action.

Notably, the authors estimated that between 25% and 30% of calories consumed in Brazil come from UPFs. "Independent of the amount of calories, independent of the amount of healthy food that you try to eat, the ultra-processed food is not good for your cognition," said Suemoto.

Even more concerning, a 2016 study found that UPFs make up roughly 58% of all calories consumed in the United States—a finding that could signal trouble for the average American, said a representative for the Alzheimer's Association.

"Ultra-processed foods make up more than half of American diets," said Percy Griffin, director of scientific engagement for the Alzheimer's Association. "It's troubling but not surprising to see new data suggesting these foods can significantly accelerate cognitive decline."

According to Griffin, the "growing prevalence" of UPFs can be attributed to "a number of socioeconomic factors" including Americans not having enough money, access, or time to prepare fresh, whole foods.

Sarah Lovegreen, VP of the Alzheimer's Association of Greater Missouri, added that Americans are putting themselves at "greater risk" by consuming large amounts of UPFs.

"I know that a lot of people are looking for that magic bullet to avoid Alzheimer's disease and other chronic conditions, and what we're learning is really the best way to avoid it is finding this balance of healthy eating, great movement, staying socially engaged, [and] avoiding smoking or alcohol—those things that we know are detrimental," Lovegreen said.

ICU hospitalization may double the risk of dementia in older adults

In a longitudinal study presented at the conference, researchers analyzed 3,822 older adults across five epidemiologic cohorts at the Rush Alzheimer's Disease Center. Participants had no known dementia at the time of enrollment. Each cohort was linked to Medicare claims data from 1991 to 2018.

On average, participants were roughly 73 years old at the start of the study. Overall, they were tracked for about 7.8 years from the time of their enrollment. About half of the participants (52.1%) had an ICU stay—27% before they enrolled in a Rush study and 25.1% during follow-up.

To assess incident Alzheimer's and all-type dementia, researchers used annual standardized cognitive testing. They adjusted for baseline measures of hypertension, diabetes, BMI, vascular risk factors, vascular disease burden, other chronic medical conditions, functional disabilities, depression, and physical activity, MedPage Today reports.

According to Bryan James of Rush University, older adults who had an ICU stay were more likely to develop all-type dementia or Alzheimer's dementia than similar participants who did not have an ICU stay.

"ICU hospitalization due to critical illness has been linked to subsequent cognitive impairment in older patients; however, few studies have demonstrated that experiencing an ICU hospitalization is related to long-term risk of developing Alzheimer's and other age-related dementias," James said.

"Given the high rate of ICU hospitalization in older persons, especially during the COVID-19 pandemic, it's critical to explore this relationship," he added. "ICU hospitalizations may be an under-recognized risk factor for dementia in older adults."

However, Wes Ely, an ICU physician at Vanderbilt University Medical Center, who was not involved with the study, noted that not all dementia takes years to manifest. 

"What we've learned in the past decade is that there are millions of people who get an acquired dementia over a period of several weeks of acute injury during an illness, whether they're in the hospital or the ICU," Ely said.

"You don't have to be in an ICU on life support to get this, but just being critically ill, you can lose millions and millions of brain cells, and then weeks and months later have an ongoing problem with memory and executive function that on cognitive testing, looks basically like Alzheimer's disease," he added. (Pertzborn/Bartiromo/Nexstar Media Wire, The Hill, 8/2; Bendix, NBC News, 8/1; George, MedPage Today, 8/2)