Longevity Briefs: The Optimal Lifestyle For Memory Function?

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: A decline in memory function seems to be an inevitable consequence of ageing, as is an increased risk of dementia. There’s no cure for either, but research suggests that you can preserve memory into old age through various simple interventions.

The most important common gene when it comes to dementia risk is the APOE gene. 15 to 25% of the general population carries the APOE e4 gene variant, which is associated with a faster rate of memory decline after middle age and a significantly higher risk of developing mild cognitive impairment (MCI) or dementia. Studies have previously looked at how lifestyle factors may improve memory function, but not much research has looked at how they interact with the APOE gene.

What did the researchers do: In this study, researchers recruited 29 000 participants aged 60 and over from 12 provinces throughout China. All participants had normal cognitive function at the start of the study. Participants were followed up for 10 years, during which time six healthy lifestyle practices were recorded:

• Healthy diet: Intake of fruits, vegetables, fish, meat, dairy products, salt, oil, eggs, cereals, legumes, nuts, and tea.
• Physical exercise: At least 150 min of moderate or 75 min of vigorous activity per week.
• Social contact: Participation in meetings or attending parties, visiting friends or relatives, travelling, and chatting online.
• Cognitive activity: Writing, reading, playing cards, mahjong, and other games.
• No smoking: Had either never smoked or not smoked within the last 3 years.
• No drinking: Did not drink or drank very rarely.

Participants were divided into carriers and non-carriers of the APOE e4 allele. They were then categorised based on how many of the healthy lifestyle practices above they adhered to, and were followed up for 10 years to assess how quickly their memories declined.

Key takeaway(s) from this research:

• Following more healthy practices was associated with a slower reduction in memory performance, regardless of whether participants carried an APOE e4 variant.
• Diet was the most impactful factor, but the number of different healthy practices seems to be more important.
• Following more healthy practices was associated with reduced risk of dementia and MCI, regardless of whether participants carried an APOE e4 variant.

Participants who followed 4-6 healthy practices had a significantly slower rate of memory decline when compared to those who followed no more than one, regardless of whether or not they carried an APOE e4 variant. Following 2-3 healthy practices was also associated with significant benefit in both carriers and non-carriers, slowing memory decline by about half as much as following 4-6 practices.

Overall, participants following 0-1 practices were about 40% more likely to develop mild cognitive impairment or dementia compared with people following 2-3. They were about ten times more likely to develop MCI or dementia compared with those following 4-6 practices. When grouped according to APOE variants, the researchers found similar results.

When looking at each different lifestyle factor individually, the researchers found that diet had the strongest association with slower memory decline, followed by cognitive activity, physical exercise and social contact.

Since no participants were younger than 60 at the start of the study, some of the benefit seen could be because participants had already been practicing healthy lifestyle habits throughout their lives. Participants weren’t perfectly representative of the population, tending to be healthier than average, and self-reporting of health practices make the reported figures less accurate. Regardless, there are already plenty of good arguments to be made for engaging in all of the practices studied in this paper.