Associations between diet quality and global cognitive ability across the life course: Longitudinal analysis of the 1946 British Birth Cohort

Authors: CARA, KELLY - Tufts University; SCOTT, TAMMY - Tufts University; CHUNG, MEI - Tufts University; JACQUES, PAUL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2025
Publication Date: 1/31/2025
Citation: Cara, K.C., Scott, T., Chung, M., Jacques, P.F. 2025. Associations between diet quality and global cognitive ability across the life course: Longitudinal analysis of the 1946 British Birth Cohort. Current Developments in Nutrition. 10(2). https://doi.org/10.1016/j.cdnut.2025.107619.
DOI: https://doi.org/10.1016/j.cdnut.2025.107619

Interpretive Summary: Gradual cognitive decline is a natural part of aging. But a more severe decline than expected could be a sign of age-related degenerative brain diseases, like Alzheimer's disease (AD). Healthy dietary patterns have all been associated with lower levels of cognitive decline and dementia, but it is not clear if there is a stage in life when diet might have the greatest impact on later life cognitive. Most evidence relating diet and cognitive function comes from populations aged 60 years or older, but efforts to prevent cognitive decline may be less effective in older adults as the onset of pre-clinical AD symptoms can occur 15 to 20 years prior to AD symptoms onset. Therefore, dietary improvements up to mid-life (age 40-65) may be most effective at preventing, slowing, or halting deleterious cognitive outcomes while improvements to diet after this stage may be less impactful. The current study investigated associations between dietary patterns and global cognitive ability across the life course to identify the stage in life when diet is most predictive of global cognitive ability trends. While dietary patterns and cognitive outcomes are often studied together in later life, this study found that dietary patterns in mid-adulthood (before age 50) may be more predictive of cognitive trends through age 69.

Technical Abstract: Background: Diet is a risk factor for later life cognitive decline and dementia. The long-term relationship between diet quality and cognitive function is unknown. Objective: This study investigated dietary pattern and cognitive ability trends over the life course and identified the life stage when diet may impact cognitive ability most. Methods: Using longitudinal data from the prospective 1946 British Birth Cohort (n = 3,059, 50.2% male), this study applied group-based trajectory modeling to identify trends in 2020 Healthy Eating Index (HEI) scores from age 4 to 63 and trends in global cognitive ability from age 8 to 69. Diet was assessed by recalls and food diaries. Cognitive ability was measured with internally developed and standardized tests. Multinomial logit models identified which factors predicted being in the lower cognitive trajectories compared with the highest trajectory. Results: A dual trajectory analysis of a four-group cognitive model and three-group dietary pattern model showed most participants in the lowest cognitive trajectory were from the lowest dietary trajectory (57.9%) with few from the highest dietary trajectory (6.9%). Conversely, the highest cognitive trajectory mostly had participants from the moderate dietary trajectory (56.6%) with few from the lowest dietary trajectory (7.8%). A multinomial logit model adjusted for HEI scores at age 4, 36, and 43, plus baseline predictors, showed age 43 dietary patterns alone significantly predicted less risk of membership in all three lower cognitive trajectories compared to the highest trajectory (relative risk ratio [95% CI] range = 0.94 [0.93, 0.96] to 0.98 [0.96, 0.99]). Conclusions: Findings from this study suggest life course dietary patterns and global cognitive ability are linked. While dietary patterns and cognitive outcomes are often studied together in later life, this study found that dietary patterns in mid-adulthood (before age 50) may be more predictive of cognitive trends through age 69.