Eight lifestyle changes experts recommend to protect your brain in middle age

A diet rich in fibre is associated with more beneficial cognitive outcomes, and critical chemical messengers derived from the gut microbiota affect the brain.

"We know that a diet rich in fibre tends to be associated with more beneficial cognitive outcomes," Dohm-Hansen says. "We have appreciated for some time that a lot of gut-microbiota-derived chemical messengers are incredibly helpful for the brain."

Of particular interest to scientists is butyrate, a short-chain fatty acid produced by bacterial fermentation of fibre in the gut.

"Butyrate is one of these interesting molecules that make their way across the blood/brain barrier into the brain," he says. "It seems to have very beneficial effects, particularly on the hippocampus which is the part involved in memory."

In Ireland, the average fibre intake is around 15g a day, well below the recommended 30g daily. We can make up the shortfall by consuming more wholegrains, fruit and veg, lentils, nuts, and seeds.

Mix up your exercise

"A variety of regular exercise is important for the brain," says Dohm-Hansen. "In studies, we have seen that muscle releases proteins in the bloodstream which has beneficial effects on the brain, and some of these molecules have a potent anti-ageing effect."

In a joint study between UCC's APC Microbiome Ireland and Kings College London (KCL), researchers are looking more closely at how exercise impacts our gut microbiota and brain health in middle age.

"It seems physical exercise can help to slow down the decline in overall health as we get older," says Prof Sandrine Thuret, head of the Adult Neurogenesis and Mental Health Laboratory at KCL. "Previously, it has been cardio activity such as running and cycling that has been studied but running isn't for everyone and our current research looks at the effects of a mixed approach of aerobic, strength and functional bodyweight sort of exercises performed three times a week."

Keep an eye on your blood pressure

It's wise to remember that what's good for your heart is generally good for your brain and hypertension is as important for cognitive health as it is for cardiovascular health.

Last year, a study showed that damage to nine specific regions of the brain, influencing various types of learning can be caused by high blood pressure. In the long term, that may contribute to a decline in cognitive function, such as memory loss and diminished thinking skills. Normal blood pressure for people under 80 is between 90/60mmHg and 120/80mmHg, so keep tabs on yours.

Keep your body clock to a strict routine

"A regular sleep pattern is extremely important for the brain," Dohm-Hansen says.

Getting too much or too little sleep in middle age has a particularly harsh effect on cognitive health, according to a team of Australian researchers who also published their findings last year. In their study of 29,544 adults, the team from the University of Canberra and the Australian National University found that those who regularly got less than six hours of sleep or more than nine hours or who were prone to lots of "daytime dozing" in midlife had worse brain health.

Eat a heart-healthy diet

Following a heart-friendly diet has been shown to improve cognitive function later in life. Women who followed the DASH (Dietary Approaches to Stop Hypertension) diet during middle age were found to be about 17% less likely to report memory loss and other signs of cognitive decline decades later.

In their study of 5,116 women published last year in Alzheimer's & Dementia journal, researchers from New York University's Grossman School of Medicine suggested that the DASH diet, which includes high amounts of plant-based foods and low amounts of saturated animal fat, salt and sugar, might help improve cognitive function later in life. Cutting out ultra-processed foods in middle age has also been shown to have a brain-protective effect.

Keep your brain busy

Building up your cognitive reserve by engaging in stimulating hobbies and tasks such as sudoku, crosswords, reading, organising activities and joining a quiz team is a bit like working a bicep muscle through weight training.

"There's a long-standing observation that people with a lot of high education attainments have a proportionately lower risk of dementia and even if they do get the disease, their rate of decline is less severe," says Dohm Hansen. "It is thought, but not yet categorically proven, that learning and years of brain challenges have built up their cognitive reserve or their resistance to cognitive decline, a bit like exercise strengthens muscles and slows the onset of frailty."

Early retirement can be something of a double-edged sword. On one hand, stopping work reduces stress, which is known to have a negative impact on brain health, but on the other hand, it can present a void in cognitively demanding daily tasks.

"People who retire earlier seem to have an earlier onset of dementia," Dohm-Hansen says, pointing to a 2020 Lancet report that found that people who retired early had a proportionately higher rate of dementia later in life. "It is clear that people who keep [their] brains active with spatially complex games and cognitive stimulating tasks have less of a steep decline and even sometimes a slight improvement in brain function and memory."

Eat more fermented foods

Fermented foods such as kefir, kombucha, yoghurt and parmesan cheese are a source of tryptophan, an amino acid known to influence brain function and mood. Ongoing research at APC Microbiome, University College Cork, suggests they are important brain-healthy foods. UCC researcher Ramya Balasubramanian told the Microbiology Society that fermented foods "are like winning the lottery for brain health".

Last year, researchers from the University of North Carolina presented findings to the American Society of Nutrition conference that showed a probiotic called Lactobacillus rhamnosus GG (LGG) found in fermented foods such as parmesan and yoghurt prompted gut changes that helped to prevent age-related memory decline.

Drizzle olive oil on everything

Olive oil is a staple of diets such as the Mediterranean and MIND (Mediterranean intervention for neurodegenerative delay). Thanks to its high levels of monounsaturated fats, it is known to be super-healthy for the brain. Drizzle it on any dish you make and it could make a significant difference to your cognitive health.

One of the monounsaturated fatty acids it contains is the potent oleic acid known to reduce inflammation in the body and brain.

Harvard scientists reporting in the Journal of the American College of Cardiology two years ago found that consuming just a teaspoon of olive oil daily was associated with a 12% reduced risk of death from all causes and that there was a stand-out connection between olive oil consumption and fewer deaths from degenerative brain disease.