Recognition of links between diet and mental health has snowballed in recent years. This includes the impact of nutrition on risk of dementia and Alzheimer’s disease.
Some individual nutrients have been singled out, such as vitamin B6 and omega-3. While these are important, by themselves they are no replacement for healthy dietary patterns.
In particular, the Mediterranean diet has been showered with accolades for its physical and mental health benefits.
Most people won’t argue with the fact that a healthy diet can ward off heart disease, diabetes, obesity and other chronic lifestyle ailments.
Not so many connect diet with mental health. But the brain is an organ, just like the heart, the liver and the pancreas.
It’s not just any organ. Although the brain accounts for only 2-2.7% of the body’s weight, it uses up 25% of the body’s glucose supply at rest – and this increases to 50% when it’s active.
As such, the brain is highly dependent on a regular supply of energy and nutrients from food. This fuels its structure and function, keeping us sharp and happy.
Not only does the brain need nutrients to work properly and create the neurotransmitters that keep it ticking over, it is directly influenced by signals from the gut through pathways known as the ‘gut-brain axis’.
These pathways are hormonal, neuronal and immunological. And there are trillions of little workers that help or hinder gut-brain messages: microscopic bacteria that dwell in the intestines.
These microbial communities are impacted by several factors including antibiotics, stress and excessive hygiene. They are also influenced by the food we eat.
Specifically, a diet high in sugar and processed food breeds less healthy bacteria while the beneficial microbes munch and proliferate on a whole food, high fibre diet.
There isn’t just one Mediterranean diet. Likewise, populations that live long healthy lives – with miniscule risk of dementia – have variations in their diets.
But there is no need for confusion; some basic underlying dietary principles are simple to follow.
The driving tenet is eating plenty of plant foods: fruit, vegetables, legumes, nuts, seeds and wholegrains. These are teeming with nutrients, antioxidants and fibre that promote a healthy gut and brain.
Fats are also important. In particular, extra virgin olive oil – a healthy monounsaturated fat – has numerous benefits attributed to its antioxidant properties. This oil has a high smoke point so can be used liberally for cooking as well as salads.
The diet typically includes moderate intakes of fish, which is associated with reduced risk of dementia, fermented dairy and red wine with meals. Importantly, it is low in sugar, processed foods and meat.
Nurturing a healthy lifestyle not only includes following these dietary principles; engaging in regular physical activity is also robustly linked to better physical and cognitive outcomes with aging.
Over the past decade, dementia has jumped from the fourth to the second leading cause of death in Australia – and for Australian women it has overtaken heart disease to become the top cause of death.
“With more than 436,000 Australians living with dementia and an estimated 1.45 million people involved in the care of someone with dementia, it is clearly one of the biggest public health challenges facing Australia,” said Maree McCabe, CEO of Dementia Australia.
McCabe highlights the urgent need for more investment into dementia awareness, research, treatment and care to address this major public health problem.
While memory and cognition decline with age – along with other physical faculties – dementia is not a normal part of aging.
Most common after the age of 65, dementia is a constellation of symptoms that affect brain function. It is a progressive disease with debilitating effects on thinking, memory, emotions, behaviour and ability to carry out daily activities.
Alzheimer’s disease is its most common form. Other versions include vascular dementia, dementia with Lewy bodies, Huntington’s disease, and alcohol-related dementia (Korsakoff’s syndrome – caused by vitamin B deficiency).
These all have different causes, and an early diagnosis is essential to try and identify if symptoms are treatable.
More importantly, many cases of dementia can be prevented.
It is estimated that a staggering one third to half of dementia cases can be prevented by changes in lifestyle behaviours – unhealthy habits that can slowly develop into dementia over an extended period of time.
A recent study conducted brain scans on 135 people over a 20-year period. Results showed that people with higher cholesterol had more white matter damage to the brain, suggesting poorer cognitive function and greater risk of dementia – independently of age, education and genetic dementia risk.
Lead researcher, Cassandra Szoeke, director of the Healthy Ageing Program at the University of Melbourne, says the effects are substantial, and are reinforced by another study that found the number of brain cells at age 50 can predict cognitive ability 10 years later.
Other new research that followed older adults for 15 years has shown that hardening of the arteries is a strong predictor of dementia risk.
These findings are consistent with studies showing that a healthy Mediterranean diet, high in plant foods and low in processed food, can lower risk of both heart disease and dementia.
Compelling evidence tells us that regular physical activity is an important way to stay physically and mentally healthy – even incidental daily activities and walking all add up.
And for people with dementia and restricted mobility, personalised exercise can also lift some of the burden, so it’s never too late to get moving.
Posted by ProPortion Foods Blog on Dec 7, 2018 in Cognition
New research adds to growing evidence that dementia can be prevented or delayed with modifiable lifestyle factors.
Researchers followed up more than 300 older adults in Pittsburgh, USA, for 15 years and found that the stiffness or hardening of their arteries was a strong predictor of their dementia risk.
These major blood vessels deliver oxygen and nutrients to all body organs including the brain. Arterial stiffness occurs when the vessel walls become inflamed and thick with plaque, and the heart has to work harder to pump blood through the body.
Age, hypertension, and diabetes are all risk factors for heart disease. They also increase the stiffness of arteries and have been linked to higher dementia risk.
Previous research has linked stiffer arteries to lower memory and concentration with aging. This study found that arterial stiffness was also an independent predictor of dementia.
Researchers assessed arterial stiffness using pulse wave velocity (PWV) – a measure of how long it takes for blood to be pumped through the arteries. They also took MRI scans of participants’ brains to test for signs of subclinical brain disease.
People with high PWV – hence stiffer arteries – were 60 percent more likely to develop dementia over the 15-year follow-up than those with low PWV. And although arterial stiffness is associated with risk of brain disease, controlling for that did not alter the risk.
First author Chendi Cui said, “It’s very surprising that adjusting for subclinical brain disease markers didn’t reduce the association between arterial stiffness and dementia at all.”
That’s good news, she added, because evidence suggests it’s easier to prevent arteries from becoming stiff than it is to prevent subclinical brain disease.
Arterial stiffness and other heart disease risk factors can be reduced with lifestyle habits like healthy diet, regular mobility, good quality sleep and not smoking – important for healthy aging altogether.
Addressing these well into advanced age could still have a significant impact. The long-term study above found that people who exercised at an average age of 73 had lower arterial stiffness five years later.
Even people in aged care with dementia have shown surprising benefits from individually tailored exercises.
The health benefits of a Mediterranean-style diet are also well established – including its link with healthy cognitive aging and reduced dementia risk.
The traditional diet is high in nutritious plant foods – vegetables, legumes, fruit, nuts, seeds and wholegrains – rich in extra virgin olive oil as the main culinary fat for cooking and salads, regular consumption of fish and moderate intake of fermented dairy products and red wine.
The diet is low in red and processed meats, confectionary and sugar.
It’s not only healthy; another bonus is that the recipes are yummy, cheap and simple to make, and can be made in bulk for leftovers or frozen for emergencies. What’s not to love?
People have long thought that dementia is unavoidable if you carry risky genes. Now research is slowly but surely debunking this fateful thinking as mounting evidence suggests lifestyle changes could help people retain control over their mental faculties.
In fact, a recent study collated the latest research and found that controllable factors could account for around 35% of the dementia burden – larger than that attributed to the genes typically linked with Alzheimer’s disease, the most common form of dementia.
Signposts have long pointed the way – physical conditions like hypertension, inflammation and heart disease confer greater risk of dementia. So it’s really a no-brainer that the benefits of looking after our physical wellbeing extend to better mental health.
In 2013, Spanish researchers allocated 522 people aged 55-80 at high risk for heart disease to a Mediterranean diet or low-fat diet. More than six years later, those in the Mediterranean diet group had less heart disease and scored higher on cognitive tests used for dementia.
Indeed, research has found that people who follow a Mediterranean diet have less brain atrophy and amyloid-ß that is typical of Alzheimer’s. “If you follow a Western diet, your brain ages faster. A Mediterranean diet is protective,” says neuroscientist Lisa Mosconi.
The traditional Mediterranean diet is high in plant foods: vegetables, fruit, legumes, nuts, seeds and wholegrains, and extra virgin olive oil for cooking and salads. It also features moderate consumption of fish, fermented dairy (cheese, yoghurt) and red wine with meals, and very little processed food or meat.
Physical activity has numerous health benefits, from reducing risk of heart disease and diabetes to some cancers. A grouped analysis of 15 studies in 2010 found that across the board, exercise can also protect against cognitive decline.
Other studies have shown that physical activity can enhance blood flow to the brain and increase levels of brain-derived neurotropic factor – a protective protein.
Even if you don’t fancy donning gym gear and sweating it out with aerobics classes and barbells, just taking opportunities each day to walk, move and be active will reap physical and mental rewards.
Keeping the brain active also confers striking protection against Alzheimer’s disease. Staying educated encourages new neural connections that might compensate for cognitive decline with aging. “It future-proofs your brain,” according to researcher Leon Flicker.
Even people who don’t pursue ongoing education can boost their cognitive reserves in other ways, like reading, doing puzzles or attending quiz nights. Quiz nights may have additional benefits – having a strong social network can also keep the brain healthy. Even being married reduces dementia risk dramatically.
In 2017, researchers pooled data from 27 studies on sleep. They found that sleep problems increase risk of cognitive impairment by 65% and could account for up to 15% of Alzheimer’s diagnoses.
Other protective factors include not smoking and maintaining a healthy weight and blood pressure.
Even if you have a genetic predisposition for Alzheimer’s disease, “there are still things you can do,” says Finnish geriatric epidemiologist Tiia Ngandu.
Richard Isaacson has set up a clinic for preventing Alzheimer’s in the US. The clinic offers individualised prevention strategies for people at risk for dementia.
Based on data they have collected, he estimates that 60% of lifestyle recommendations will apply to most people. Beyond that, strategies may vary from person to person, including, for instance, specific treatments for heart conditions or sleep problems.
Researchers are now optimistic that people can prevent their risk of dementia, and current large studies are underway to strengthen the evidence base.