How to eat to keep your brain young
Recent research has found that you can slow brain ageing by boosting the health of your gut. Experts explain what foods can help you to do this.
Most of us are now familiar with the idea that boosting our gut health can transform our physical wellbeing. But scientists are discovering that the state of our gut microbiome, the vast collection of bacteria, fungi and yeasts that inhabit our digestive tract, may also hold the key to brain health — not only in protecting cognitive function but in reversing the damaging effects of ageing on our brains.
Scientists have known for some time that a two-way communication system exists between the gut and brain, known as the “gut-brain axis”. By chemically altering nerve signals going to the brain, gut bacteria have been shown to change brain chemistry in a way that influences behaviour, mood and cognition.
But earlier this year, in a study from the APC Microbiome Ireland at University College Cork, one of the world’s leading research centres into gut health, the neuroscientist John Cryan showed for the first time how we might be able to slow and even reverse brain ageing by improving levels of beneficial bacteria in the gut.
For a trial published in the Nature Aging journal, Cryan and his team revealed how transferring the gut bacteria of healthy young mice into older animals produced significant changes in ageing brains. It actually reversed the ageing of the hippocampus, part of the brain responsible for memory.
“Epidemiological studies have previously shown us that healthy brain ageing is associated with certain types of diet, but nobody had figured out what was making that happen,” he says. “It is now clear that our gut microbes are affecting all aspects of our health, including brain health.”
As we get older, the number and variety of beneficial bacteria we harbour in the microbiome declines. “This decline is made worse by the fact that we tend to become more rigid in our diets as we get older, eating less variety and fewer of the foods that can boost our microbiome,” Cryan says.
“In our latest study we were surprised to find that by keeping microbes young and diverse we could reverse many of the processes of brain ageing.”
“There are practical ways to help stave off cognitive decline, and improving gut health through nutrition and diet is the best way.”
Here are the foods that can help to boost your microbiome and reverse brain ageing.
Eat asparagus, artichokes and bananas
Asparagus, artichokes, leeks, chicory and bananas contain inulin, a form of soluble fibre that nourishes beneficial gut microbes. In one of Cryan’s studies published in the journal Molecular Psychiatry two years ago, a 14-week inulin-rich diet was shown to reduce inflammation of immune cells in the brain called microglia, key players in neurodegenerative conditions such as dementia. The anti-ageing effects were in the hippocampus, the brain region that regulates learning and memory.
“We showed that we could slow down brain ageing when this prebiotic was provided,” Cryan says. “It follows that we should all make an effort to get more inulin our diets through food.”
Increase your consumption of fermented foods
Fermented foods including kombucha, kimchi and sauerkraut, made by combining milk or vegetables with micro-organisms such as yeast and bacteria, are full of live microbes.
In a recent study at Stanford University, published in the journal Cell, researchers showed that adults who were asked to increase their intake of fermented foods from almost nothing to about six servings a day (a small pot of yoghurt or a small cup of kimchi classed as a serving) had a much greater diversity of gut microbes and lower levels of inflammation after 10 weeks than those who ate no fermented foods.
Drink kefir — but make sure it’s good quality
Many people drink kefir, the traditionally fermented milk drink, because it’s fashionable and they have heard it’s good for gut health, but until recently there were few studies proving its health benefits. Now in several studies, including one published in the journal Microbiome last year, the APC team have shown how kefir consumption influences the gut-brain axis to improve behaviour, memory, learning and mood.
Paul Cotter, an adjunct professor and head of the food biosciences department at University College Cork, stresses that not all kefirs are equally beneficial. “It is a case of buyer beware,” he says. “Some companies call their products kefir but it really isn’t anything more than a dilute yoghurt, while others contain a long list of micro-organisms.”
You should be looking for a lengthy list of 15 or more microbes, including “a range of Lactobacillus, yeasts, enterococcus and possibly some Leuconostoc bacteria”, Cotter says.
“My recommendation is to consume it daily, preferably after a meal when stomach acid is reduced so that the microbes stand a better chance of getting through to the gut,” Cotter says.
Eat good cheese
Cheese is a rich source of microbes. “Most cheese varieties are fermented in some way and therefore contain bacteria that are beneficial for the gut,” Cotter says. But not all contain the same amount of microbes.
“For consistency, many mass-produced cheeses rely on just one or two microbes as opposed to the 10-20 that might be present in cheeses made to traditional methods,” Cotter says. “The advice is to buy artisanal cheeses if you can or to get as wide a variety as possible.”
Eat leafy green vegetables every day
Fibre feeds our gut bacteria, and one of the best ways to boost our daily intake is through leafy green vegetables. “Try to eat as much fibre as you can tolerate in your diet,” Cryan says. “Eating more green veg, a wonderful prebiotic, is one of the best forms of fuel and will impact the health of our brain.”
What to avoid
Cryan advises cutting out processed food, which he goes so far as to describe as having an “evil” effect on our microbiome. “We should avoid it as much as possible and also cut out foods with artificial sweeteners and emulsifiers for the same reasons,” he says.
“In addition, you should minimise antibiotic consumption and try to avoid missing out on sleep as those are also unhealthy for the state of our microbiome.”
The Times
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