Is coffee actually good for you? Here's what the research says

According to the British Coffee Association, we drink around 98 million cups of coffee in the UK each day. Globally, approximately 2 billion cups are downed a day, making it the most popular drink in the world.

But should we be wary about coffee? After all, so many of life's delicious things have some kind of negative health impact. It's hard not to notice the difference that coffee can have on people, with the effects of caffeine and some people's seeming dependence on the drink.

Well, one review of research says that not only is coffee consumption generally safe within regular levels of intake, but it might even go so far as to reduce your risk of several health conditions.

Does the research provide grounds for drinking more coffee? And how much might be a good amount to drink? Let's take a look and see what the study authors found.

What did the review reveal about coffee consumption?

For the most part, the researchers found that drinking coffee was associated with a range of risk reductions for different health conditions, depending on the amount that people had drunk.

In the study, published in The BMJ in 2017, researchers reviewed meta-analyses examining coffee consumption and its association with various health outcomes.

The review included 201 meta-analyses of observational research looking at 67 different health outcomes, plus 17 meta-analyses of interventional research looking at nine different health outcomes. This makes it one of the largest evidence reviews to date.

The most significant risk reductions were associated with drinking three to four cups of coffee a day compared with not drinking any at all. These were a reduced risk of death from all causes, death from cardiovascular issues specifically, and cardiovascular disease.

Drinking high levels of coffee was associated with an 18% lower risk of developing cancer compared with drinking low levels of coffee. And drinking coffee in general was associated with a lower risk of a number of specific diseases, including certain cancers, liver conditions, and neurological issues.

The biggest effects overall were related to liver diseases. Drinking coffee was associated with a 29% lower risk of non-alcoholic fatty liver disease, 27% lower risk of liver fibrosis, and a 39% lower risk of cirrhosis compared with not drinking coffee.

The researchers did note some sex-related differences, however. During pregnancy, high levels of coffee drinking were associated with negative birth outcomes such as preterm birth and pregnancy loss.

There was also an association between coffee and risk of bone fractures for females, but for males, the association was with a lower risk.

Overall, this review is very positive, suggesting that you might stand to gain a lot from regular cups of coffee. But what is it about coffee that might provide these potential benefits?

Why might coffee affect health outcomes?

As well as being a delicious warm drink to many people, we know that coffee contains lots of different active compounds that can have an effect on our bodies.

While most coffee contains caffeine, which has some antioxidant properties, it can also contribute a large number of antioxidants to our diets, such as chlorogenic acid.

Coffee also contains two chemical compounds, cafestol and kahweol, that can have antioxidant and anti-inflammatory effects, particularly against carcinogens.

It's the effects of all these compounds that the researchers suggest could be behind the associations they found in their review.

We should point out that many of the beneficial associations spotted by the researchers were similar for both caffeinated and decaffeinated coffee, suggesting that caffeine isn't the key compound in the brew.

On top of this, none of the harmful associations that the researchers found for caffeinated coffee was present for decaf.

Although the researchers don't mention it, it's also worth noting that coffee contains a decent amount of soluble dietary fibre. You'll find 0.47-0.75 grams of fibre in 100 millilitres of coffee, depending on how it's prepared.

Fibre-rich diets help support your gut health and are associated with reduced risks of heart disease, stroke, bowel cancer, and type 2 diabetes.

Are there any limitations with this coffee research?

There are several caveats to this research review that we should bear in mind.

Although the researchers reviewed 218 meta-analyses for their paper — a huge amount — only 17 were intervention studies. This means that a large chunk of the data the researchers worked with was from observational studies, leaving room for the associations to be driven by things other than coffee consumption.

Not only is there scope for associations in observational studies to be confounded by other factors — smoking, overall diet, or exercise, for instance — but the door is also open for reverse causality. Might people be drinking more coffee because they are healthier?

To their credit, the authors did note that most of their evidence is low in quality, and that genetic analysis or randomised controlled trials would be necessary to give firmer conclusions.

It can be tricky to get a clear handle on how much coffee people are actually drinking too. There's no standardised volume for one cup of coffee, which could lead to treating espresso cups the same way as your biggest coffee mug.

In addition to the study findings that associate coffee drinking with negative pregnancy outcomes and an increased risk of fractures for some people, other research is less positive about the potential impact of the drink.

A more recent systematic review published in Nutrition Research Reviews investigated the influence of coffee by looking at genetic variations associated with its consumption.

The authors of this review paint a different picture, suggesting that many of the benefits reported by observational studies are not supported by the genetic research they analyse in their research.

The systematic review did find some positive associations, however. These were decreased risks of migraines, kidney disease, gallstone disease, ovarian cancer, and a type of liver cancer called hepatocellular carcinoma.

They conclude that overall, there's little evidence of harm relating to coffee consumption, and that drinking one to three cups a day appears to be a generally safe amount.

So while the picture might not be as exciting and rosy as the 2017 research review suggests, there's still some potential good news to be had for coffee aficionados.

So, should we all be drinking coffee?

If you're a coffee drinker, the first bit of good news is that the research indicates that for most people, it's all good to drink.

Both the research review and the systematic review we've looked at suggest that consuming up to three cups of coffee a day is generally safe, and is an amount associated with some health benefits.

So, coffee could be a good thing to drink. It's just important not to get too carried away due to the potential limitations the research review has.

If you do drink coffee, here are a few things worth thinking about:

• Think about how you brew: Making coffee through boiling, as an espresso, or with a cafetiere yields larger amounts of the antioxidant and anti-inflammatory cafestol and kahweol compared with instant and filtered coffee. On the other hand, filtered coffee may have less of an impact on blood fats such as LDL cholesterol than boiled coffee. So if this is a metric you're looking to manage, filtering could be the way to go.
• Don't dismiss decaf: Decaf coffee tends to get a bad rap, but the research here is supportive. The researchers found no harmful associations between drinking decaf and health outcomes. The decaffeination process does little else to the composition of your coffee, so you may get many of the same potential health benefits with it that you might with the regular variety, minus whatever effects that caffeine might bring to the table.
• Try green tea if coffee isn't your thing: If you're looking for a healthful beverage, an alternative might be green tea. One meta-analysis of randomised controlled trials has suggested that it might aid glucose level management, while another noted that it could help with lowering blood pressure.
• Take care if you're pregnant or at higher risk of bone fractures: If you're pregnant or a female with an increased risk of bone fractures, it may be best to look for coffee alternatives.

If you're curious about the potential impact of coffee on LDL and other blood lipids, a Thriva blood test can help you test and track your levels at home.

Takeaway

A large review of meta-analyses reported many associations between coffee drinking and health benefits. We should be wary about drawing firm conclusions, though, due to the limitations of the evidence used alongside the findings of other more recent research.

A more recent systematic review of genetic studies did find some other positive health associations, however. And with some exceptions, the research suggests coffee is safe to drink, and that one to three cups a day is an amount most often associated with health benefits.

Disclaimer: This information is for general educational purposes only and isn’t a substitute for professional medical advice, diagnosis, or treatment. Always speak with a qualified healthcare professional first if you have concerns about your health.