Balanced diet associated with better cognitive function

Maintaining a balanced energy intake through diet was associated with significantly better cognitive function compared with uneven intake patterns, researchers reported in Life Metabolism.

Hui Chen, PhD, vice dean of the department of psychology and behavioral sciences at Zhejiang University in China, and colleagues conducted a community-based cohort study to assess whether or not the timing of meals has an effect on cognitive function.

Chen and colleagues used data from the China Health and Nutrition Survey from 1997 to 2006 and included participants aged 55 years and older who completed at least one dietary assessment and cognitive test. Participants were excluded if they had severe cognitive impairment at baseline; had extreme energy intake; or had a stroke, ischemic attack, hypertension, diabetes or cancer at baseline.

A total of 3,342 individuals were included for analysis (mean age, 62.2 years). Of those, 61.2% lived in rural areas, and 13.6% achieved a high school education or higher.

The authors assessed dietary intake using a combination of weighing methods and a 3-day, 24-hour dietary recall at each wave. Average daily energy intake from breakfast, morning snack, lunch, afternoon snack, dinner and evening snack were calculated using the Chinese Food Composition Table.

The authors identified six temporal patterns of energy intake (TPEIs) — participants with a “breakfast-dominant” pattern had an average of 49.5% total energy intake (TEI) per day from breakfast. Those with a “lunch-dominant” pattern had an average of 64.3% TEI from lunch. Participants with a “dinner-dominant” pattern had 64.5 TEI. The “snack-rich” pattern was 36.8% TEI, and the “breakfast-skipping” pattern was 5.9% TEI.

Lastly those with an “evenly distributed” pattern was characterized by TEI evenly spread out among three major meals (28.5%, 36.3% and 33.8% from breakfast, lunch and dinner, respectively). A total of 33% of all participants maintained their patterns from baseline to the end of the study.

The authors assessed cognitive function through the modified Telephone Interview for Cognitive Status, comprising immediate and delayed word recalls, backward counting and the serial-7 subtraction test. Total cognitive scores ranged between 0 to 27, with a higher score representing higher cognitive function.

The authors assessed the correlation of TPEIs to cognitive function using linear mixed models and adjusted for age, sex, residence, total energy, physical activity, smoking status, alcohol consumption, household income, education level and body mass index.

Other than the evenly distributed TPEIs, all other five patterns were associated with poorer cognitive function — breakfast dominant, –0.94; 95% CI, –1.37 to –0.51; lunch dominant, –1.18; 95% CI, –1.67 to –0.69; dinner dominant, –0.97; 95% CI, –1.43 to –0.51; snack rich, –1.05; 95% CI, –1.70 to –0.40; and breakfast skipping, –1.32; 95% CI, –1.66 to –0.99.

Additionally, compared with the evenly distributed pattern, the breakfast-skipping pattern was associated with significantly faster cognitive decline by 0.14 points per year (95% CI, –0.24 to –0.04). This was significant only for individuals aged younger than 65 years.

“We observed that maintaining balanced energy intake across three major meals was associated with significantly better cognitive function than the other five unevenly distributed patterns,” the authors wrote.