A healthy lifestyle, and particularly a healthy diet, is associated with slower memory decline, a decade-long study of older adults has revealed.
Even for people with the apolipoprotein E (APOE) gene – the strongest known risk factor for Alzheimer’s disease and related dementias – a healthy lifestyle was found to slow memory loss.
“These results might offer important information for public health initiatives to protect older adults against memory decline,” say the research team.
“Prevention is important, given the absence of effective treatments for Alzheimer’s disease and related dementias.”
Memory continuously declines as people age, but evidence from existing studies is insufficient to assess the effect of a healthy lifestyle on memory in later life. And given the many possible causes of memory decline, a combination of healthy behaviours might be needed for an optimal effect.
To explore this further, researchers analysed data from 29,000 adults aged at least 60 years (average age 72; 49 per cent women) with normal cognitive function who were part of the China Cognition and Ageing Study.
At the start of the study in 2009, memory function was measured using the Auditory Verbal Learning test (AVLT) and participants were tested for the APOE gene (20 per cent were found to be carriers).
Follow-up assessments were then conducted over the next ten years in 2012, 2014, 2016, and 2019.
A healthy lifestyle score combining six factors was then calculated: healthy diet, regular exercise, active social contact, cognitive activity, non-smoking, and never drinking alcohol.
Based on their score, ranging from zero to six, participants were put into favourable (four to six healthy factors), average (two to three healthy factors), or unfavourable (zero to one healthy factors) lifestyle groups and into APOE carrier and non-carrier groups.
After accounting for a range of other health, economic and social factors, the researchers found that each individual healthy behaviour was associated with a slower than average decline in memory over ten years.
A healthy diet had the strongest effect on slowing memory decline, followed by cognitive activity and then physical exercise.
Compared with the group that had unfavourable lifestyles, memory decline in the favourable lifestyle group was 0.28 points slower over ten years based on a standardised score (z score) of the AVLT, and memory decline in the average lifestyle group was 0.16 points slower.
Participants with the APOE gene with favourable and average lifestyles also experienced a slower rate of memory decline than those with an unfavourable lifestyle (0.027 and 0.014 points per year slower, respectively).
The researchers say their results provide strong evidence that adherence to a healthy lifestyle with a combination of positive behaviours is associated with a slower rate of memory decline, even for people who are genetically susceptible to memory decline.
They suggest further research could focus on the effects of a healthy lifestyle on memory decline across the lifespan, acknowledging that memory problems can also affect younger people, not included in this study.
