Eating well boosts brain health, promotes well-being for older Singaporeans

Sustaining healthy eating habits as people age yields cognitive and psychosocial benefits in very late life, as shown in a study from Singapore.

In a cohort of Singaporean Chinese adults aged ≥85 years, those who had a “consistently high” diet quality trajectory were less likely to have cognitive impairment and depressive symptoms, in addition to being more socially active, compared with those who had a “consistently low” trajectory, according to researchers from the Singapore Institute for Clinical Sciences.

Specifically, the “consistently high” trajectory lowered the odds of cognitive impairment by 29 percent (odds ratio [OR], 0.71, 95 percent confidence interval [CI], 0.51–0.99) and of depressive symptoms by 26 percent (OR, 0.74, 95 percent CI, 0.55–0.99), as well as increased the odds of social engagement by 47 percent (OR, 1.47, 95 percent CI, 1.09–1.98). [Innov Aging 2023;doi:10.1093/geroni/igad036]

“The trajectories identified in this study suggest that dietary behaviours, which are established earlier in life remain fairly consistent in the long term until very late in life,” the researchers noted.

“Those who started with a high diet quality at late life tended to maintain a high-quality diet until very late life, which were associated with better cognitive and psychosocial well-being, [as evidenced] by lower risks of cognitive impairment and depression, and higher likelihood of social engagement,” they explained.

Diet quality

For the study, the researchers used data from 861 participants (mean age at baseline 65 years, mean age at third follow-up 85 years, mean age at fourth follow-up 88 years). Diet quality was evaluated based on adherence to the Dietary Approaches to Stop Hypertension (DASH) pattern, and group-based trajectory modelling was used to derive diet quality trajectories over the past 2 decades.

At the fourth follow-up, all participants completed assessments for cognition (Singapore-modified Mini-Mental State Examination), depressive symptoms (15-item Geriatric Depression Scale), social engagement, and self-rated health.

Diet quality trajectory was “consistently low” for 49.7 percent of participants and “consistently high” for 50.3 percent. Participants in the “consistently low” trajectory group had an average DASH score of 18 or 19 points at each time point, while those in the “consistently high” trajectory group maintained their DASH scores at an average of 24 points at all three time points. Of note, those with “consistently low” diet quality trajectory tended to have the lowest educational level, to be smokers, and to have the lowest physical activity level at baseline.

No statistically significant association was seen between the diet quality trajectories and self-rated health.

“Approximately half of the study sample had a low-quality diet from late to very late life. Although these individuals survived until very late life, their poor diet over time was associated with increased likelihood of cognitive impairment, depression, and social isolation,” the researchers said. “This is concerning and underscores the need for more interventions and health promotion efforts to support these individuals to adopt a healthier diet as they transition from late to very late life.”

A life-course approach

Taken together, the present data underscore the importance of considering health and well-being throughout all stages of life, according to the researchers. They pointed out that lifestyle behaviour interventions that advocate high-quality diet have to be performed early, that is in the decades leading up to very late life, to achieve optimal cognitive health and psychosocial well-being in later years.

“Nevertheless, our findings need to be interpreted with caution in the absence of baseline cognitive and psychosocial outcomes to rule out reverse causality, as it is possible that those with consistently high diet quality over time already had lower prevalence of cognitive impairment and depressive symptoms, and higher prevalence of social engagement at baseline, than those with consistently low diet quality,” according to the researchers.