Is Coffee Really Good For Us? We Asked A Nutritionist

Our new columnist, Dr Federica Amati, head nutritionist at ZOE, unpacks the latest science on coffee, including the health benefits and impact on the gut microbiome.

What Are The Health Benefits Of Coffee?

Coffee’s shared history with humans stretches back many centuries, and it remains one of the world’s most popular drinks with 80 percent of the population drinking it daily. As scientists study how coffee might affect health, the media eagerly reports their studies – journalists know most of us have skin in the game and want to know whether coffee is killing us. Over the years, the pendulum has swung between headlines like ‘Coffee Is Bad for Your Heart!’ and ‘Coffee Is Actually Great for You!’. But what’s the truth?

To understand the full picture, we first need to separate coffee from caffeine, the most well-known of coffee’s many fascinating plant compounds. It’s an important part of the plant’s defence system, protecting it from being snacked upon or infected. We call these kinds of plant chemicals bioactive because they have specific effects, but what about its effects on humans? 

How Does Caffeine Affect The Body?

Caffeine acts on the central nervous system, making it the most commonly consumed psychostimulant drug in the world. Famously, it can make you feel more awake and alert, but studies also show it can improve athletic performance and thinking. Interestingly, despite past headlines to the contrary, moderate caffeine consumption isn’t bad for your heart. Now that scientists have run larger and longer studies, it’s clear that, for generally healthy people, coffee reduces your risk of heart disease. There’s also some evidence that caffeine may protect against Alzheimer’s and Parkinson’s.

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Caffeine is, of course, addictive, and withdrawal can be generally unpleasant, bringing headaches, fatigue and low mood. Some people respond poorly to caffeine, too – it can make them jittery and anxious and interrupt their sleep even many hours later. If you’re sensitive to caffeine, decaf coffee still has health benefits, thanks to the cocktail of plant chemicals it contains.

Raw coffee beans contain hundreds of plant chemicals. As part of the coffee-making process, beans are fermented – legions of bacteria process the raw ingredients, converting the cocktail of natural plant compounds into a dizzying array of new ones. These plant compounds and their fermentation likely impart many of the health benefits associated with coffee.

How Does Coffee Impact Gut Health?

This links to a topic close to my heart: the gut microbiome. Although the term ‘gut health’ has become a marketing buzzword, the science linking gut bacteria to overall health grows stronger with each study published. For instance, a recent study by ZOE scientists found they could identify who drank coffee just by analysing their gut microbiome. We also identified a species of bacteria called Lawsonibacter asaccharolyticus that thrive in the presence of coffee, which may help explain some of coffee’s health benefits. 

Coffee’s influence on the gut microbiome is partly thanks to plant compounds called polyphenols. They feed your ‘good’ gut bacteria, helping them thrive and multiply, displacing ‘bad’ species. Polyphenols also support antioxidant processes in your cells that mop up toxic byproducts of metabolism and may reduce your risk of heart disease and inflammation, and even help protect against type 2 diabetes.

Aside from the benefits of polyphenols, coffee supports gut health as it contains a fair dose of fibre. In the UK, guidelines suggest we eat 30g of fibre a day, but we only manage 20g on average. Fibre helps protect against heart disease, metabolic conditions and cancer; it also supports healthy blood sugar control, immune function, digestion and even weight management. Coffee contains around 1.5g of fibre per cup, which is more than a glass of orange juice. Although it won’t be enough fibre to fulfil your dietary requirements, it’s a good start.

Beyond the gut, evidence suggests that drinking moderate amounts of coffee may also be associated with a lower risk of some cancers, including breast, liver, prostate and colorectal cancer. Although experts are unclear on the precise mechanisms involved, it seems likely that coffee’s incredible suite of plant compounds play an outsized role.

As always, there are caveats to be aware of – not all coffees are created equal. Many coffee products contain high levels of sugar, and coffee’s powerful plant compounds can’t counteract that. Many also contain a range of additives, including emulsifiers, which are likely to impact the health of your gut microbiome.  

Overall, the latest science shows that moderate coffee consumption can support your health. And while caffeine has certain benefits – if the buzz is unpleasant, decaf and its powerful polyphenols will still provide benefits.

What To Look For

1. Check the ingredients. If a product has lots of added sugars or a long list of hard-to-pronounce ingredients, don’t buy it. 
2. Black is best for maximum benefits, but a splash of milk, whether it’s dairy, oat, or any other plant milk, will do no harm. 
3. Don’t frown on instant. The evidence suggests that, healthwise, it is just as beneficial. If that’s your cost-effective, simple-to-make coffee, you’re not missing out.