Coffee-lovers, I have good news… you absolutely don’t need to cut it out altogether for good gut health!
Several studies have found health benefits to drinking coffee regularly (in moderation), linked to lowering the risk of type 2 diabetes, liver disease and certain cancers, to name a few. But how does it actually work?
Well, this hasn’t been totally figured out. It’s been previously suggested that it could be thanks to anti-inflammatory effects or protection against free radicals – but researchers have argued this activity is too weak to have such health effects.
Now a 2020 review published in Nutrients suggests that coffee, as a plant food, could have similar beneficial properties to many fruits and vegetables. While directly comparing coffee to fruit and veggies is a bit of stretch – of course, it’s not that simple (let’s not forget the all-important fibre!) – here’s what they found…
Polyphenols: the health effects are thought to be largely thanks to the health-promoting polyphenols found in coffee, which could work by the same process in the body as fruit and vegetables do (as they’re also packed with polyphenols). For regular coffee drinkers, coffee is the primary source of polyphenols in the developed world (followed by tea).
“Healthy” plant food: Coffee literally comes from plant origins and there’s no reason to think the beneficial plant chemicals in coffee are any less “healthy” than those in tea, vegetables or fruits. The researchers even suggested coffee beans could be seen as a healthy plant food – employing similar pathways for improving our health as seen for other plant foods, such as broccoli, beetroot, berries, pomegranate, cocoa and others.
Coffee types: Dark roast coffee appears to be a more powerful activator of antioxidant and protective activity than light coffee.
Coffee and our gut microbes
Coffee may have extra health-promoting effects happening in the gut too. Researchers also suggested that coffee may have a prebiotic effect (remember a prebiotic is food for beneficial microbes) which could also play a role in its health effect, by influencing the make-up and function of the gut microbiota (GM) – just like other plant foods can.
Studies have shown coffee consumption is linked to an increase in Bifidobacteria in humans and animal studies. And Bifiobacteria, in turn are linked with a wide range of health benefits including better mental health.
Much of the microbial ‘magic’ lies in the polyphenols we touched on above. These polyphenols aren’t digested in the small intestine – instead, they travel down into the large intestine where our GM lives. Our microbes help to transform them into a range of beneficial chemicals that can be absorbed into our body, linked with better heart health, mental health and reducing risk of cancer.
More long-term studies need to be done to fully understand the role of our GM in the health effects of coffee – but it most certainly busts the myth that coffee is ‘bad’ for the gut!
What about caffeine?
The health effects, including the lower risk of type 2 diabetes, have still been seen with decaffeinated coffee, so it doesn’t seem to be down to the caffeine content.
Instead, it seems to be other key components of coffee that are associated with health benefits – i.e. the polyphenols and other beneficial plant chemicals.
How much is too much?
Most adults can have up to 400mg of caffeine a day without any side effects, which is approx. 3 filtered coffees (200mg during pregnancy), but some people can be a little more sensitive and can experience things like nervousness, anxiety, insomnia and gut symptoms. Why some people and not others? It’s related to both genetics and how the caffeine is broken down by your body.
With coffee, the naturally occurring caffeine content can vary depending on the plant variety, growing conditions and brewing method, so it can be tricky to know exactly how much you’re having.
As a general guide:
When it comes to gut issues, what’s right for you really depends on your personal situation.
Diarrhoea: If you’re experiencing diarrhoea, coffee can stimulate the colon so it’s worth trying to lay off the coffee until your gut has settled.
IBS: It’s worth checking if caffeine affects you. If so, try switching to decaf options
Constipation: Coffee can enhance the mass movement of your gut, which essentially increases your urge to poop (you’ll know this if you always tend to go after your morning coffee!)
Take-home message
While no amount of coffee can ever replace good old fruits and vegetables (sorry, coffee-lovers!), regularly drinking coffee in moderation can absolutely be part of your gut-loving lifestyle as a good source of beneficial polyphenols. It’s no miracle drink, so remember to fill up on fibre too from all your plant-based foods, along with your morning coffee.
If you’re into the nitty-gritty science…
The mechanism: how it works
The researchers identified a mechanism of action as being common to coffee, vegetables and fruit. Essentially, when we consume them, certain proteins that help to protect our cells respond, which in turn triggers an increased expression of cell defence genes. These are involved in antioxidative, detoxifying and DNA repair processes in the body.
