How to nurture a healthy brain for life (Part 7 of Your Brain at 100)

This is part 7 of a series of lessons in brain health from our elders — those folk who lived the longest and healthiest. Click here to download the entire series as a PDF

Dementia, memory loss and cognitive decline are robustly related to old age, and AD is one of the leading causes of death globally. So, is the payoff for a longer life memory loss and poor brain health in our final years?

To answer this question, I’ve look to two sources — those exceptionally old folks who remain in robust physical and mental health until the very end of their lives, and our evolutionary past.

Over millennia, Mother Nature has equipped us to survive and thrive in the wild. Our brains evolved such that from the womb to the tomb we’re required to move, eat well, sleep, immerse ourselves in nature, avoid stress, love and befriend, and seek meaning. These requirements neatly match the everyday life prescriptions followed by the world’s longest-living people.

Prevention is our best defence and the research on dementia is clear. Those of us who lead mentally, socially and physically stimulating lives have reduced risk of age-related brain disease. If we live as close as possible to how Mother Nature intended, while reaping the rewards of our modern healthcare, there is every chance we can add not only years to our lives but life to our years.

Our human ancestors likely evolved facing similar survival challenges to other species.

Whereas the need to acquire food was a major day-to-day challenge during much of our evolutionary history, today we live with a constant oversupply of food.

Today, our intellectual challenges focus on work or education, rather than the challenge of acquiring food.

Neuroscientist and ageing researcher, Prof Mark P. Mattson writers in Ageing Brain Reviews.

Regular intellectual challenges are critical for brain development and a successful career, and recent findings suggest that intermittent exercise and energy restriction can further enhance and then sustain the functional capabilities of the brain during aging.

Rather like an animal in the wild, our intellect evolved to function optimally when we’re motivated towards a goal, slightly hungry, and on foot, a state Mattson likens to ‘Hunger Games’ bolstered brainpower. 

In a 2017 Trends in Neurosciences paper, University of Arizona researchers David Raichlen and Gene Alexander support Mattson’s case that our brains are a product of our evolutionary history and our past as hunter-gatherers.

They argue as humans transitioned from a relatively sedentary ape-like existence to a more physically demanding hunter-gatherer lifestyle, starting around two million years ago, we began to engage in complex foraging tasks that were simultaneously physically and mentally demanding, and that may explain how moving and thinking came to be so connected.

Notably, the parts of the brain most taxed during high cognitive load tasks such as foraging (the pre-frontal cortex, hippocampus and entorhinal cortex) are the same areas that show vulnerability in Alzheimer’s disease.

When faced with inactivity as is so common in our modern-day life, our brains adaptively reduce capacity as part of an energy-saving strategy, leading to age-related brain atrophy…

The evidence from modern science and ancient wisdom is clear. How we eat, move, sleep, form relationships and find meaning is intimately connected to how our brains grow, think, feel and, ultimately, age.

1. The best exercise for your brain is physical exercise

Our brains and nervous systems evolved to move us around and to sense and perceive the world. Our cognitive prowess and human intellect evolved while we were on foot. Our brains evolved, not to think or feel, but to control how we move. Therefore, moving is the best way we know to keep our brains fit and well.

A Canadian review of twenty-four randomised control trials and twenty-one prospective cohort studies calculated that at least one in seven cases of AD could be prevented if everyone who is currently inactive took up exercise.

People living in Blue Zones people don’t run marathons, wear Fitbits, or join Crossfit gyms. Instead, they live in environments that constantly ‘nudge’ them into moving without thinking about it. Jeanne Calment rode her bike till she was 100, and lived in a second-story apartment with no lift until she was 110.

2. Eat real food, not too much, mostly plants

Our ancestors and their smart brains were trotting across the landscape hunting, fishing and foraging for food. We evolved to eat food from the rivers, forest and sky. We are also adaptable, and the many versions of a healthy ‘diet’ vary by country, culture (and today by social media platform). What sets those who live the longest apart is not the minutiae of their diet and balance of nutrients gained from fats, protein or carbohydrates, but the absence of refined processed foods.

Evidence from epidemiological studies such as the Blue Zones and clinical trials strongly implicates a Mediterranean-style diet slows brain ageing.

And most recently, a clinical trial in Australia proved successful in treating depression by encouraging young people with depression to up their consumption of vegetables, fruits, wholegrains, legumes, fish, lean red meats, olive oil and nuts, while reducing their consumption of unhealthy ‘extras’ foods, such as sweets, refined cereals, fried food, fast-food, processed meats and sugary drinks.

When we eat, we’re consuming not only nutrients but energy in the form of calories. Researchers, such as the Dunedin Study team, are now unravelling the relationships among calories, lifespan, healthspan and cognitive health. Calorie restriction (eating less) and intermittent fasting (fasting on and off) increases longevity in all species thus far observed, from yeast to rodents to primates — it’s assumed the same is true for us.

This notion ties back to the ‘Hunger Games’ concept whereby our brains evolved to function most optimally when we’re hungry and looking for food. Eating less benefits our glucose control, cholesterol and may produce mild neuronal stress which engages signalling pathways that improve the ability of the brain to resist ageing.

Dietary advice for brain health can be summed up by Michael Pollen’s famous adage,

Eat real food, not too much, mostly plants.

3. Get more sleep

As earthlings, our biological rhythms are determined by the rising and setting of the sun. Our sleep patterns, when hormones are released, our blood pressure and body temperature, ebb and flow in sync with day and night.

Modern-day life with its artificial lighting late at night, alarm clocks, shift work, iPhones in bed, and jetlag, is very good at interfering with our natural sleep patterns. As a basic biological function, sleep is overlooked and underappreciated, and globally, modern humans are chronically sleep-deprived.

Sleep deprivation (even a few hours a night) impacts cognition, mood, memory, and learning, and long-term leads to chronic disease including depression, diabetes and cardiovascular disease, all risk factors for developing dementia.

A good night’s sleep every night should be a priority, not a luxury. And my personal daily indulgence, a short afternoon nap, consolidates memory, sparks creativity and smooths your rough emotional edges, giving you greater control over your thoughts and feelings.

4. Challenge your mind

Lab mice kept in bare cages with no toys or places to explore show greater rates of age-related cognitive decline compared to their counterparts kept in enriched novel environments full of toys, tunnels and mazes. As we’ve discussed, humans are no different.

People who stay mentally engaged in life and constantly challenge themselves to step out of their comfort zone have reduced risk of age-related cognitive decline and dementia.

Children have a natural tendency to run and play, whereas adults tend take life more seriously. We don’t lose the need for novelty and pleasure once we grow up. Game playing, whether it be video or online, traditional board games, dancing, or team or individual sports, has been shown to alleviate boredom, anxiety, depression, loneliness, despair and even physical pain.

As Charlene Levitan said to me,

We don’t stop playing and learning because we get old, we grow old because we stop playing and learning.

5. Find your place or moment of calm

One pervasive theme I came across writing my book was how stress ‘gets under our skin’ to influence our mental and physical health decades later.

Not all stress is bad, but chronic or toxic stress, especially life events that are out of our control, have deleterious effects.

The key to buffering stress is to find ways to improve your perceived ability to cope with whatever life throws your way. Find peace amid the chaos. Find your place or moment of calm.

The evidence is mixed whether or not stress causes dementia, but it’s clear stress hormones alter risk for anxiety, depression, obesity and cardiovascular disease, which in turn increase dementia risk.

More has been spoken or written about the practice of mindfulness meditation in recent years than any other previously free stress-relief practice. With good reason. Paying attention to your breath, which is a core component of many mindfulness practices, reduced anxiety and depression, and improves sleep.

Blue Zones people have in place varied daily rituals that reduce or buffer the impact of stress in their lives. Activities include prayer, napping and happy hour with friends. (I’ll add walking the dog or enjoying a good book to the mix.)

6. Connect with family and friends

After we foraged, caught or hunted our food, we trotted back to our tribe. Being socially connected to other people protects against stress and because socialising involves many cognitive functions such as thinking, feeling, sensing, reasoning and intuition, friendships contribute to cognitive reserve.

Old age brings ‘costs of survivorship,’ and a ‘thinned’ social landscape. Richard Setterson writes,

We lose people with whom we shared many experiences, who are central to our identities, and who are no longer there to validate — or to question — our memories or accounts. This kind of identity loss also occurs with the death of older generations, as we are pushed up the family ladder and, once at the top, become orphans in time.

A 2010 meta-analysis of 148 studies including 300 000 people who were tracked for 7.5 years after completing surveys of how often they met with family and friends, found socially connected folks live longer.

On the flipside, loneliness was associated with late-life loss of cognition, including elevated blood pressure, depression and poor sleep. The startling conclusion of this report was that the influence of social isolation on the health and risk of death was comparable to smoking.

7. Seek out meaning and purpose

With purpose and meaning comes positive emotions — love, compassion, and appreciation — which counteract stress and support a healthy brain throughout life. Blue Zones residents are members of faith communities and find meaning and purpose through spirituality. Living a meaningful life seems an unlikely addition to a book about the brain, but ‘purpose in life’ is a concept in neuroscience that links to robust brain and mind health.

Purpose, defined as the tendency to derive meaning from life’s experiences and to possess a sense of intentionality and goal-directedness that guides behaviour, can be quantified.

A study published in Archives of General Psychiatry in 2010 examined the association of purpose in life with risk of AD in more than 900 elderly people living in residential care. During the seven years of follow-up, greater purpose in life was associated with a substantially reduced risk of AD, such that a person with a high score on the purpose in life measure was approximately two and half times more likely to remain free of AD than a person with a low score.

Have you figured out why you’re here?

What’s your north star? Your ‘ikigai’. Your ‘plan de vida’? There are possibly many clever strategies to find meaning of your life — somewhere in the nexus of passion, skillset, employment opportunity, education and service to others. William James the psychologist said in 1920,

The deepest principle in human nature is the craving to be appreciated.

Recently I’ve come across a simpler way. Over the years, I’ve taken taken stage with Paul Baldock, a bone biologist at Sydney’s Garvan Institute of Medical Research. We called on to share our wisdom, purpose and what we’ve learned on our career paths in science. Baldock has developed a novel formula for every decision he makes in the research lab, career, and life. He simply asks,

Is it awesome? Does it help?

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This is part 7 of a series of lessons in brain health from our elders — those folk who lived the longest and healthiest. Click here to download the entire series as a PDF