February 8, 2023
Memory typically declines with age, but engaging in healthy lifestyle activities can help to keep the memory sharp into old age, according to a new report. The study found that a healthy lifestyle, and particularly a healthy diet, was associated with slower memory decline in old age. A healthy lifestyle also helped protect against the onset of Alzheimer’s disease, including among those who have a higher genetic risk of developing the illness.
For the study, researchers in China reviewed health records from 29,072 men and women age 60 and older. Their average age was 72, and all were free of Alzheimer’s disease or other serious memory issues at the start of the study, in 2009. The researchers also did follow-up memory assessments over the next decade, in 2012, 2014, 2016 and 2019.
Researchers also recorded whether they carried the APOE-E4 gene variant. People who carry this genetic variant, especially when they carry two copies, are at increased risk of developing Alzheimer’s disease, though not everyone who has the gene will develop dementia. In the study, about 20 percent of participants had the APOE-E4 gene variant.
In addition, the researchers focused on six lifestyle factors that are known to lower the risk of Alzheimer’s disease. They were:
Regular physical exercise
At least 150 minutes of moderate exercise or 75 minutes of vigorous exercise per week was considered a healthy factor. These levels are consistent with the American sports guidelines for physical activity in adults.
Study participants were grouped as to whether they were current smokers, had never smoked (fewer than 100 cigarettes in their lifetime) or were former smokers (those who had quit smoking at least three years previously). Never smoking and former smoking was considered a healthy lifestyle factor.
Researchers recorded participants’ typical alcohol consumption and grouped them into never to low drinking (those who never drank or drank occasionally), moderate drinking (one to a few drinks a day on average) and excess drinking (four or more drinks a day on average). A low level of drinking was considered a healthy lifestyle factor.
A healthy diet
Researchers recorded participants daily consumption of 12 food groups — fruits, vegetables, fish, meat, dairy products, salt, oil, eggs, cereals, legumes, nuts and tea. Their intake was deemed healthy if they consumed recommended amounts of at least seven of the 12 food items daily. Recommended amounts typically mean eating more of heart-healthy foods like fruits, vegetables, fish, nuts, olive oil, grains and tea and less of foods like red meats, salt, butter and other saturated fats and eggs.
Researchers assessed whether participants engaged in mentally stimulating activities like writing, reading, playing cards, mahjong or other games, or doing puzzles or other mental challenges. Engaging in such activities at least twice weekly was considered healthy.
Active social contact
Social interaction is good for the brain. Participating in activities like going to meetings or parties, visiting friends or relatives, traveling, and chatting online at least twice weekly was considered a healthy factor.
The researchers then grouped participants according to how often they typically engaged in these healthy lifestyle behaviors. Those who typically engaged in four to six healthy factors were put in the favorable group; those who engaged in two or three were put in the average group; and those who did one or none were placed in the unfavorable group. They were then sub-grouped according to whether they carried the APOE-E4 gene variant.
After accounting for a range of other health, economic and social factors, the researchers found that each individual healthy behavior was associated with a slower than average decline in memory over 10 years. A healthy diet had the strongest effect on slowing memory decline, followed by cognitive activity and then physical exercise.
Participants with the APOE-E4 gene who had favorable and average lifestyles also experienced a slower rate of memory decline than those with an unfavorable lifestyle.
What’s more, compared to those in the unfavorable lifestyle group, those with favorable lifestyles were almost 90 percent less likely to develop Alzheimer’s disease or mild cognitive impairment (MCI), which often precedes dementia, over the 10-year course of the study. Those in the average lifestyle group were 30 percent less likely to develop Alzheimer’s or MCI. The findings were published in the British medical journal The BMJ.
“The results of this study provide strong evidence that adherence to a healthy lifestyle with a combination of positive behaviors, such as never or former smoking, never drinking, a healthy diet, regular physical exercise, and active cognitive activity and social contact, is associated with a slower rate of memory decline,” the authors conclude.
Healthy lifestyle factors may be especially important in those who have a genetic predisposition to Alzheimer’s disease in their family. “APOE E4 is the strongest known risk factor for Alzheimer’s disease and related dementias,” write the authors of an editorial accompanying the study. “These results support the notion that lifestyle change might counteract the deleterious effect of APOE-E4 on cognitive decline and dementia.”
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Sources: Jianping Jia, Tan Zhao, Zhaojun Liu, et al: “Association between healthy lifestyle and memory decline in older adults: 10 year, population based, prospective cohort study.” The BMJ, January 25, 2023
Séverine Sabia, Archana Singh-Manoux : “Healthy lifestyles for dementia prevention An increasingly urgent public health priority” (editorial). The BMJ, January 25, 2023