The mysteries of our ageing brain

Reader’s Digest: The UK population is getting older and we’re led to believe we have diminished brain function to look forward to as we age. But you claim that ageing is good for the brain. How so, and where’s the evidence?

André Aleman: Well, there are certainly cognitive functions that diminish somewhat with ageing, such as a reduction of mental speed and of memory performance. But there are also mental abilities that improve with ageing, such as the ability to make complex decisions and to deal with emotions. Elderly people have more experience stored in their brains, which benefits decision-making. It may also explain why they are a bit slower: there is more information to go through.

RD: Can you share examples of the research you’ve undertaken to show us that brain ageing is not all doom and gloom?

AA: We’ve shown that physical exercise is associated with good cognitive functioning in elderly people, so it’s not only good for your physical health but also for keeping your mind sharp to work out at the gym or go for a brisk walk every day. Our studies have also shown, as did a host of other studies worldwide, that elderly people are good with verbal knowledge (e.g. vocabulary). They even outperform younger people. We are currently investigating the brain function, using MRI scans, of elderly people with memory problems to see whether those with a degree of apathy (lack of initiative to undertake daily activities) are at a higher risk for dementia.

RD: How often we hear the elderly apologise with, "My memory isn’t what it used to be!" Is memory a medical condition? How do we distinguish between early onset dementia and forgetfulness?

AA: It's not always an easy distinction. Everybody forgets names and appointments every now and then. But if it becomes very frequent, it could be a reason to visit your GP. Especially when others confirm that your memory is worse than usual for more than a few weeks, or when you start getting into difficulties finding your way to familiar places.

RD: What do you mean by "successful ageing"?

AA: This is a concept that has emerged from research among elderly people that experience a high level of well-being. It refers to several factors: the avoidance of disease and disability, the maintenance of high physical and cognitive function, and sustained engagement in social and productive activities. It doesn't always mean absence of certain chronic health problems, but that they are well under control and do not hamper what we want to do in our daily lives.

RD: In your book, you talk about the population in Okinawa, Japan, being remarkable for having the oldest and healthiest people in the world. What are the scientific reasons for this?

AA: Researchers have identified several reasons for healthy ageing among Okinawan people. One of those is the fact that in their culture the elderly are well respected and seen as a valuable asset to society. The feeling of being valued is good for your well-being. Another factor is their level of physical activity. Genetics also plays a role, but cannot explain more than 30% of the difference between Okinawan and Western elderly people. The most important factor seems to be diet. The Okinawan diet is characterised by moderate calorie intake, plenty of fruits and vegetables and low levels of saturated fats and sugar. Numerous studies have shown such a diet to be good for brain function.

RD: Do fish oils work? And what about health supplements in general?

AA: Studies have shown a small positive effect of fish oils on cognitive functioning. If you have a healthy diet, other health supplements don't really seem to add anything. There is no evidence that they can help fight decline.

RD: Mindfulness is a hot topic, with pages on the subject appearing in the press and on the internet. How do you see the mindful approach to living leading to an improvement in brain function?

AA: Mindfulness has been shown to be associated with reduced levels of stress – and prolonged stress is an enemy of our brain. Brain-imaging studies have recently shown that a mindful attitude, which can be enhanced by mindfulness training, improves the ability to regulate emotions. Brain regions involved in controlling and changing negative feelings, for example, are able to exert stronger control as a result of mindfulness training.

RD: You talk about the five-point plan. What is it and will it really help us have the best possible brain?

AA: Marian Diamond, a well-known neuroscience professor from California, developed a five-point plan to keep the brain young: diet, exercise, challenges, newness and love. By challenges, she meant engaging in activities that demand effort, intelligence or creativity. She advised looking for new stimuli – reading something different, or visiting new places and meeting new people. At the age of 82 she still gave lectures at the university. Her plan is definitely well supported by scientific evidence. I very much like her suggestion regarding the importance of love, as social relationships with close others are highly valued by older people and essential for their wellbeing.

RD: Thinking ahead to the distant future, will medical science advance so much that we will be able to enhance our brain function beyond its current capability? For example, can we one day be treated to have a photographic memory or learn a new language at supersonic speed? What does the future hold in store for brain power?

AA: Frankly, we don't know what will be possible in the future. There have been several recent advances in neuroscience that we may not have thought to be possible in the past. For example, using neurostimulation with magnetic pulses we can directly influence brain-activity patterns. This is already being used in the treatment of depression. Other novel methods such as optogenetics even enable researchers to change behaviour in rats by driving brain activity in specific areas. There are also new developments in brain-computer interaction. It's clear that such developments will raise important ethical questions, which will need to be addressed in interaction with society. 

Andre Aleman is the author of Our Ageing Brain: how our mental capacities develop as we grow older, published by Scribe. Read an extract here. 
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