Can a multicultural healthy diet reduce cognitive decline and Alzheimer's disease risk?

By Dr. Sanchari Sinha Dutta, Ph.D.Nov 16 2022Reviewed by Aimee Molineux

Scientists conducted a pilot randomized controlled clinical trial to investigate whether a multicultural healthy diet can reduce cognitive decline and Alzheimer’s disease risk in adults aged 40 – 65.

They have published novel study protocols for ambulatory cognitive assessment and web-based dietary intake assessment in Contemporary Clinical Trials.

Background

Alzheimer’s disease and related dementia (ADRD) are highly prevalent in the United States. The number of adult Americans living with ADRD is expected to increase from 6.2 million to 12.7 million by 2050.

Diet is a potentially modifiable risk factor for ADRD and related cognitive decline. An anti-inflammatory diet, including high amounts of vegetables, fruits, whole grains, and fish, is known to reduce cognitive decline and improve mood.

The current study aims to investigate the effects of a multicultural healthy diet in reducing the risk of Alzheimer’s disease and cognitive decline in a diverse population of adults living in the Bronx, New York.

Study design

The current randomized controlled trial is the first of its kind to combine novel ambulatory cognitive assessment methods with a web-based dietary intake recording assessment. This ambulatory strategy assessed cognition and diet in real-time over seven days every nine months. This led to a collection of 140 assessments of cognition and 28 days of diet records in real-time per person.

The study participants were randomly categorized into two groups. The multicultural healthy diet group participants were exposed to the dietary intervention over 18 months. The sustainability of the intervention was assessed for an additional nine months.

The participants in the control group were exposed to standard healthy diet intervention over the same period. Both conventional in-clinic and ambulatory methods were used to assess the study outcomes. The ambulatory methods were applied to mirror the natural setups in which people perform cognitive tasks in their daily lives.

Mobile Monitoring of Cognitive Change (M2C2) smartphone application was used for the ambulatory assessment of various cognitive tasks, including processing speed, visuospatial working memory, short-term associative memory binding, long-term associative memory, and working memory capacity.    

Daily dietary intake was recorded using National Cancer Institute’s Automated Self-Administered 24-hour (ASA24) food records.

Survey design

A total of six surveys, including one “wake-up survey,” four “notified surveys,” and one “bedtime survey,” were administered each day via the smartphone application.

The wake-up survey was designed to collect information about the previous night’s sleep pattern, expectations for the day, self-ratings of cognition, momentary food record, and physical activity before the wake-up survey.

The notified survey was designed to collect information about the self-rating of emotional behaviors and cognition, ratings of time pressure and distraction since the last survey, momentary food records, and physical activity records. The bedtime survey also followed the same design as a notified survey.

Ambulatory cognitive assessments were performed at the end of each wake-up and notified survey. Dietary records were collected during each ambulatory assessment.

Study outcomes

The study assessed a global composite cognition score derived from the M2C2 ambulatory cognitive assessments at nine months post-study commencement. Moreover, the study assessed the adaptability of a multicultural healthy diet in a diverse population of adults in the Bronx, New York.

Several serum biomarkers, including total folate and vitamers, tocopherols, carotenoids, vitamin B12, and fatty acid profile, were measured at nine months to determine the impact of dietary intervention. Self-reported consumption of food items, such as fruits and vegetables, was assessed.

Both short-term and long-term associations between dietary intervention and cognitive performance were assessed.   

Study significance

The ambulatory cognitive and dietary intake assessments performed in the study provide a rich real-time database to characterize the impact of dietary interventions on cognitive performance in adults.

The study includes ambulatory and in-clinic cognitive assessments for comparison and validation. The ability of ambulatory assessments to collect data remotely is particularly effective in a restricted situation like the coronavirus disease 2019 (COVID-19) pandemic. While in-clinic assessments have been discontinued during the pandemic, the cutting-edge ambulatory methods have allowed the study to continue with minimal interruptions.