
A gut feeling: exploring the world of ‘psychobiotics’
Patsy Westcott
You don’t have to eat fermented cabbage to boost your levels of good bacteria
We really are what we eat, with every mouthful we take affecting the trillions of bacteria that live in our gut. There’s growing evidence that this microbiome can affect everything from our digestion and immune system to our moods and heart health.
A survey by OnePoll found 40% of people don’t realise its importance – and with expensive, niche, fermented products such as kimchi, kefir and kombucha always hyped as the best way to boost good bacteria, perhaps it’s no wonder the message isn’t getting through.
We really are what we eat, with every mouthful we take affecting the trillions of bacteria that live in our gut. There’s growing evidence that this microbiome can affect everything from our digestion and immune system to our moods and heart health.
A survey by OnePoll found 40% of people don’t realise its importance – and with expensive, niche, fermented products such as kimchi, kefir and kombucha always hyped as the best way to boost good bacteria, perhaps it’s no wonder the message isn’t getting through.
Yet there are plenty of other, rather more alluring foods that will do the job. It’s all about embracing a wide variety in the diet, says Laura Southern, nutritional therapist at London Food Therapy. “People assume you need fancy foods such as sauerkraut, but the most important thing is variety, with fibre from grains, fruit and vegetables to feed resident microbes, plus live dairy products to provide extra bacteria. Cutting back on processed food controls the bad bacteria.”
We look at some of the foods and drinks that research suggests can help maintain a healthy gut – without fermenting a single cabbage.
A swift half might actually be good for you according to research in June 2022 from NOVA University in Lisbon. A small group of men aged 23 to 58 were given a 330ml bottle of lager (Super Bock) every night for a month.
Scientists then used stool analysis to measure healthy stomach bacteria and discovered it had increased by 7%. That’s thought to be because plant micronutrients called polyphenols provide fuel for gut microbes.
Beer is the only source of hop polyphenols in the human diet. Professor Eric Claassen, a scientist from the University of Amsterdam, recommends Belgian beer for gut health.
He says that the double-fermentation process of beers such as Hoegaarden and WestMalle Tripel produces an acid that kills bad bacteria in the stomach. However, experts say the effects are only felt with one drink a night.
Dark chocolate is full of cocoa polyphenols, plant chemicals known to be anti-inflammatory, good for your heart, and which also have a big impact on digestive health.
“There’s a symbiotic relationship between the polyphenols in chocolate and your intestinal microbes,” says nutritionist Kim Plaza at Bio-Kult supplements.
“Your gut microbes make the polyphenols more readily available and absorbable, while the polyphenols influence the bugs to grow. It’s best to eat raw or 80% dark chocolate.”
Fans of sourdough have long claimed it is easier to digest than standard bread, and science is proving them right.
In a study at the University of Bolzano in Italy in 2021, volunteers who were given sourdough bread had evidence of healthier microbes in their colons than those given commercially produced bread.
Researchers found higher amounts of resistant starch and amino acids in sourdough (food for gut bacteria), due to the wild yeast starter and long fermentation process.
In 2020, scientists at the University of Illinois found that study participants who ate one avocado a day had a greater abundance of microbes in their intestines after 12 weeks. They also had a more diverse array, all of which is good news for gut health.
It’s all to do with the monounsaturated fats and fibre in avocados, according to Southern. “There’s a lot of fibre in an avocado – approximately 12g – which provides food for your bacteria. The good fats act as a lubricant to help prevent constipation.”
Yogurt gets much fanfare, but did you know cheese can contain just as many live bacteria?
A study by scientists at the Universities of Copenhagen and Aarhus found that people eating a cheese-heavy diet for two weeks had higher amounts of short-chain fatty acids in the intestine, indicating an increase in gut flora.
Cheeses with a probiotic punch have typically been aged but not heat-treated: mozzarella, cheddar and Parmesan.
Feta is rich in Lactobacillus plantarum (good bacteria found in fermented foods), and a study by a biotech company found that Roquefort has anti-inflammatory properties that are good for the stomach.
It’s not often the humble white potato wins health accolades (its sweet cousin hogs the limelight), but a study at China’s Jiangsu University in 2021 might change that.
Scientists found that potatoes increase the abundance of good bacteria in the gut and reduce bad bacteria. “Potatoes are full of resistant starch, a type of fibre that travels to the large intestine to become a food source for resident bacteria,” says Southern.
“How you cook potatoes makes a big difference to resistant starch. One of the best ways is to boil new potatoes, put them in the fridge and eat them cold the following day. Sadly, chips aren’t a great source!”
Good news for red wine drinkers – they have a more diverse range of flora in their gut than drinkers of other types of alcohol, according to a 2019 study by King’s College, London.
Scientists studied 458 pairs of twin sisters and put the results down to the high concentration of polyphenols in red wine, which act as fuel to the microbiome.
A Spanish study backs this up, finding that a large glass of Merlot increases two types of bacteria in the gut associated with slimness and low cholesterol.
Don’t say we don’t sometimes bring you good news.
This article first appeared in the September 2022 edition of Saga Magazine. Like what you’ve read? Subscribe to Saga Magazine today.
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Written by Ruth Tierney
Published: Updated: