A new study has found that a healthy lifestyle, particularly a healthy diet, is associated with slower memory decline in older adults.
The study published in The BMJ followed 29,000 adults over the age of 60 for a decade in China.
At the start of the study, participants’ memory function was measured using the Auditory Verbal Learning test (AVLT) and they were also tested for the APOE gene, which is a known risk factor for Alzheimer’s disease and related dementias. Follow-up assessments were conducted every two years for a total of ten years.
The researchers calculated a healthy lifestyle score for each participant based on six factors: a healthy diet, regular exercise, active social contact, cognitive activity, non-smoking, and never drinking alcohol. Participants were then divided into three groups based on their score: favourable (4-6 healthy factors), average (2-3 healthy factors), or unfavourable (0-1 healthy factors).
The study found that each individual healthy behaviour was associated with a slower than average decline in memory over the ten-year period. A healthy diet had the strongest effect, followed by cognitive activity and physical exercise.
Compared to the unfavourable lifestyle group, the favourable lifestyle group had a 0.28 point slower decline in memory over ten years, and the average lifestyle group had a 0.16 point slower decline. Participants with the APOE gene who had favourable or average lifestyles also experienced a slower rate of memory decline than those with unfavourable lifestyles. Additionally, those with favourable or average lifestyles were almost 90% and almost 30% less likely to develop dementia or mild cognitive impairment.
The study’s authors note that it is an observational study and cannot establish cause, and there are limitations such as potential measurement errors and selection bias. However, they say that the large size and long follow-up period of the study provide strong evidence that adherence to a healthy lifestyle is associated with a slower rate of memory decline, even for those who are genetically susceptible. They suggest that further research should focus on the effects of a healthy lifestyle on memory decline across the lifespan.