What happens to our health when we drink coffee every day?

Numerous studies show that your morning cup of coffee not only wakes you up for the day, but also gives a boost to the billions of beneficial microbes in your digestive system.

There is growing evidence that your coffee may positively impact your microbiome (gut bacteria), leading to better overall health and even a longer life.

“The microbiome contains legions of good bacteria that work together and individually to improve our health,” says nutritionist Nicola Schubrock. “These microbes are increasingly seen as benefiting our metabolic health, weight management and mental health. Coffee contains several compounds that act as prebiotics, meaning they feed the beneficial probiotic bacteria by providing them with the nutrients they need to grow and function.”

Caffeine itself acts as a stimulant, increasing the number of beneficial bacteria in the gut, and “the more diversity you have in your digestive system, the better,” says Schobrooke.

Results of a 2023 study published in the journal Nutrients showed that regular coffee drinkers had higher microbiome richness, with increased numbers of beneficial Alistipes and Faecalibacterium bacteria (which are thought to have protective effects against liver cirrhosis and cardiovascular disease), and lower levels of harmful Erysipelatoclostridium bacteria, which cause gut problems.

Coffee also contains plant compounds called polyphenols, a class of compounds found naturally in plant foods, such as fruits, vegetables, herbs, spices, tea, dark chocolate and wine.

"Polyphenols act as an anti-inflammatory and antioxidant. They can help reduce the risk of cancer by neutralizing harmful free radicals, chemicals that destroy cells," Schawbrook points out.

The specific polyphenol found in coffee is known as chlorogenic acid. According to a 2020 study, patients who consumed coffee rich in chlorogenic acid had a reduced risk of developing type 2 diabetes and non-alcoholic fatty liver disease, and they also lost weight.

Studies have also shown that caffeine is good for the intestines, as it stimulates the colon and leads to regular bowel movements.

Experts tend to agree that black coffee is better than cappuccino or latte. “Milk has been shown to hinder the absorption of polyphenols,” says Julia Kupczynska, a microbiologist at the Polish Institute of Biochemistry and Biophysics in Warsaw. “Adding cream or sugar turns your coffee into a dessert. Sugars do more harm to blood sugar levels than coffee ever could.”

There are two main types of coffee: Arabica and Robusta. “Each has different characteristics at certain roasting stages,” says Kopczynska. “Although lighter roasts generally have higher caffeine content, they retain more antioxidants than dark roasts. Lightly roasted Robusta beans have more antioxidants than lightly roasted Arabica.”

The length of time the beans are stored will also affect polyphenol levels, with a noticeable decrease in coffee beans stored for 12 months or more.

While studies suggest that instant coffee may contain more polyphenols and minerals than ground coffee, it also contains 100 percent more of a chemical called acrylamide. “Acrylamide is formed in coffee during the roasting process, and if people are exposed to it in higher amounts, they may be at increased risk of nerve damage and cancer,” says Kopczynska. However, studies on the chemical’s link to cancer are mixed, meaning there’s no solid evidence that coffee consumption, whether instant or ground, is linked to the development of cancer.

How many cups should I drink a day?

A recent study of centenarians living in the European Blue Zones of Sardinia and Ikaria, Greece, revealed that almost all of them drink two to three cups of black coffee daily.

"Although coffee is beneficial, not everyone can metabolize it efficiently. The recommended maximum amount of caffeine is 400 mg per day. Anything over 600 mg is linked to insomnia and high blood pressure," Schubroek stresses.

Can I make my coffee healthier?

Adding natural spices, rather than sugars or syrups, can provide additional health benefits. Kupczynska recommends adding cardamom, noting that it is “anti-inflammatory and regulates blood sugar levels.” She also recommends ginger, which is a natural pain reliever, improves digestive health and lowers cholesterol. “If you use milk, adding turmeric to your latte is known to have beneficial effects on metabolism and the immune system,” she adds.