Eating a high-quality diet during adolescence and middle age may help preserve good brain function in older age, according to new preliminary findings from a study using data collected from following more than 3,000 people for nearly 70 years.
The study adds to the growing body of evidence that a healthy diet can help prevent Alzheimer’s disease and age-related cognitive decline. Most previous research on the topic has focused on the eating habits of people in their 60s and 70s, but the new study is the first to track diet and cognitive performance across the lifespan (from age 4 to 70), suggesting that the link may begin much earlier than previously recognized.
“These initial findings broadly support current public health guidelines that recommend establishing healthy dietary patterns early in life is important for maintaining and supporting health throughout life. Our findings also provide new evidence suggesting that improved dietary patterns by midlife may influence cognitive performance and potentially mitigate or reduce cognitive decline later in life.”
Kelly Kara, PhD, recent graduate of the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University
Cara will present her findings at NUTRITION 2024, the American Academy of Nutrition’s flagship annual meeting, taking place in Chicago from June 29 to July 2.
Cognitive ability, or thinking skills, can continue to improve into middle age but typically begins to decline after age 65. Along with age-related decline, more severe conditions such as dementia can also develop. Researchers say that a healthy diet, especially one rich in plant-based foods high in antioxidants and monounsaturated and polyunsaturated fats, can support brain health by reducing oxidative stress and improving blood flow to the brain.
In the new study, the scientists used data from 3,059 British adults who were enrolled as children in a study called the National Health and Development Survey. Members of the cohort, called the 1946 British Birth Cohort, have provided data on their dietary intake, cognitive ability, and other factors through questionnaires and tests for more than 75 years.
The researchers analyzed participants’ dietary intake at five time points in relation to their cognitive performance at seven time points and found that diet quality was closely associated with trends in general or “overall” cognitive performance: for example, only about 8% of people consuming a low-quality diet maintained high cognitive performance compared to their peers, and only about 7% of people consuming a good-quality diet maintained low cognitive performance.
Cognitive ability can have an important impact on quality of life and independence as we age. For example, at age 68-70, participants in the highest cognitive ability group showed much greater retention of working memory, processing speed, and general cognitive ability compared to participants in the lowest cognitive ability group. Furthermore, at this time point, nearly a quarter of participants in the lowest cognitive ability group showed signs of dementia, while none of those in the highest cognitive ability group showed signs of dementia.
While diet quality improves steadily throughout adulthood for most people, the researchers noted that small differences in diet quality during childhood appear to set the tone for later eating patterns, for better or worse. “This suggests that early childhood dietary intake influences later dietary decisions and that cumulative effects of diet over time are associated with overall cognitive development,” said Kara.
To assess diet quality, the researchers used the 2020 Healthy Eating Index, which measures how closely a person adheres to the Dietary Guidelines for Americans 2020-2025. Compared to their peers, study participants who maintained the highest cognitive performance over time tended to eat more of recommended foods, such as vegetables, fruits, legumes, and whole grains, and less sodium, added sugars, and refined grains.
“Dietary patterns rich in whole or less processed plant foods, such as leafy green vegetables, beans, whole fruits, and whole grains, may be the most preventative,” Kara says. “Adjusting dietary intake to include more of these foods and be more in line with current dietary recommendations at any age may improve health in a number of ways, including cognitive health.”
Because study participants were primarily white across the UK, the researchers said further research is needed to determine whether their findings apply to populations with more racial, ethnic and dietary diversity. They also noted that changes in study focus and protocols over the course of the longitudinal study created some gaps and inconsistencies in data collection. But despite these limitations, the researchers were able to use data from multiple cognitive domains to create a global cognitive ability percentile rank score and assess how participants compared to their peers at each age and over time.
Kara The study will be presented at the “Food Timing and Dietary Patterns: Health Implications in an Aging Society” session on Monday, July 1, from 4:36 to 4:48 p.m. CDT at McCormick Place.Abstract; Presentation details).
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American Academy of Nutrition
