Numerous studies have shown that a cup of joe is good for the gut – but what’s the best way to prepare it, and are some better than others?
That morning cup of coffee doesn’t just wake you up for the day, it also gives a boost to billions of friendly microbes residing in your digestive system. Because, according to a growing body of research, there is evidence that your espresso may positively influence your microbiome – gut bacteria – leading to better overall health and even a longer life.
“The microbiome comprises legions of species of ‘good bacteria’ that work collectively and individually to improve our health,” says Nicola Shubrook, a registered nutritionist and functional medicine practitioner.
“These microbes are increasingly being seen to benefit our metabolic health, weight management and mental health,” she continues.
“Coffee contains several compounds that act as a prebiotic, which means that they nourish the probiotic beneficial bacteria by providing them with nutrients necessary for growth and function.”
The impact of coffee on our gut flora appears to be twofold. Firstly, caffeine itself acts as a stimulant, increasing the number of helpful bacteria in the gut. “The greater the diversity in your digestive system, the better,” says Shubrook.
The specific polyphenol in coffee is known as chlorogenic acid. According to a 2020 study published in Experimental and Clinical Sciences, patients who consumed coffee rich in chlorogenic acid lowered their risk of Type 2 diabetes and non-alcoholic fatty liver disease – they also lost weight. Scientists concluded this was probably related to an increase in intestinal bifidobacteria (one of the “good” ones).
Established studies have also shown that caffeine is good for your gut, stimulating the colon and leading to regular bowel movements. One 1990 study showed that people who drank coffee tended to need the loo 30 minutes after drinking a cup.
In so many ways, the gut appears to love a cup of Joe. But is there a best way to prepare and serve your coffee?
Black or with milk?
Experts tend to be unanimous that black coffee is better for you than a cappuccino, latte or flat white.
“Milk has been shown to impede the absorption of polyphenols,” says Julia Kopczyńska, a microbiologist at the Polish Institute of Biochemistry and Biophysics in Warsaw. “Adding tons of cream or sugar turns your coffee into a dessert. Sugars will do more harm to your blood sugar levels than coffee can do good.”
Which blend should I choose?
There are two main types of coffee bean: Arabica and Robusta. “Each has different qualities at particular roasting stages,” says Kopczyńska.
“Though lighter roasts generally have a higher caffeine content, they preserve more antioxidants than darker roasts. Light-roasted Robusta beans have more antioxidants than the blonde roasts of Arabica coffee.”
Most UK chain coffee shops use medium-roasted Arabica beans, although Costa does sell a blend of Arabica and Robusta. Black Sheep Coffee also sells Robusta.
“My go-to is Exhale Coffee, which is a dark Arabica grown with the highest level of antioxidants,” says Shubrook. “It’s the perfect black coffee, not at all messed with.”
The length of time the beans have been stored will also influence their polyphenol levels, with a reduction seen in coffee beans stored for 12 months or longer.
What about instant coffee?
Though studies show that instant coffee may contain even more polyphenols and minerals than ground coffee, it also contains 100 per cent more of a chemical called acrylamide – coffee substitutes can even have 300 per cent more. “Acrylamide forms in coffee during the roasting process and if people are exposed to it in higher amounts, they could raise their risk of nerve damage and cancer,” says Kopczyńska.
There is no cause for alarm, however. “Coffee consumption, both instant and ground coffee, is not linked to cancer development,” Kopczyńska continues. “However, the European Food Safety Authority (EFSA) recommends reducing the amount of acrylamide in our diet. This is why we also recommend classic ground coffee above instant and substitutes.”
How many cups should I drink a day?
A recent study of the centenarians living in the European “long life” Blue Zones of Sardinia and Ikaria, Greece, revealed that almost all of them drank two to three cups of black coffee a day.
“Presuming a cup of coffee is 8oz/ 220ml, two to three cups is the sweet spot, with five the upper limit,” says Kopczyńska.
Before grinding your beans or stamping your loyalty card, it’s worth bearing in mind the caffeine content of your drink. “Although coffee is beneficial, not everyone can metabolise it as efficiently,” notes Shubrook. Kopczyńska agrees.
“The maximum recommended amount of caffeine is 400mg a day. Anything above 600mg has been linked to insomnia and high blood pressure.”
Can I make my coffee healthier?
Adding natural spices – as opposed to sugars or syrups – can bring extra health benefits.
“Cardamom is an anti-inflammatory and regulates blood sugar levels,” advises Kopczyńska. “Ginger, a natural painkiller, improves digestive health and lowers cholesterol.
If you’re using milk, turmeric added to a latte is known for its beneficial effects on metabolism and the immune system.”
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