Increasingly, we see headlines about the positive health effects of coffee. This seems to be a huge swing away from a couple of decades ago where coffee seemed to be bad for us and was blamed for interrupting our sleep and making our hearts pound in a bad way. So, what has brought about this change in thinking?

One reason is that the way coffee is made in some countries has changed. Some of the original research focussed on coffee, once popular in Sweden, which was made by boiling ground coffee. This type of filtered coffee has been associated with increased risk of heart disease, but it’s not seen where the coffee isn’t boiled and is filtered. The reason for this is not entirely clear, but some studies have suggested that unusual types of fat in the coffee can alter how our bodies make and use fats and cholesterol. In theory, this could increase risk of heart disease. In addition, this type of coffee has become less popular with the rise of people drinking other types of coffee such as espresso.  

Different countries, different coffees?

Coffee is not the same world over and it’s unlikely that the coffee in many of the studies carried out around the world are the same as the one served in your local coffee shop such as the salted caramel latte with extra whipped cream and sprinkles! In a recent analysis of a Greek population, we attempted at least to see if a research group I am involved in could standardise the coffee drunk in Greece so that the results could be compared to those in the rest of the world.

This wasn’t a simple task, as it may not be the same drink, even before the milk and extras are added. The good news is that it was found that it doesn’t have to be a posh fresh coffee to suggest health benefits, instant coffee seems to be just the same as fresh, with or without caffeine.

Be wary of the caffeine

Until recently, most of the focus on coffee has been about the caffeine it contains. The average cup of coffee contains about 90mg of the stuff (depending on the type of coffee and how it’s made). A double espresso, the typical base for many coffee shop coffees, will contain about 125mg and the more shots you have in your coffee means that you will get more caffeine.

Health organisations around the world suggest that most people can safely consume up to 300mg of caffeine a day. Some people are advised to consume less though. The NHS suggests that pregnant women consume no more than 200mg, or 2 cups, of caffeinated coffee a day. This is because studies have linked caffeine intake (not coffee intake) with low birth weight babies. Pregnancy aside, the safe limits are set because research has linked intakes of over 600mg a day to insomnia, nervousness, irritability, increased blood pressure and upset stomachs, although response to caffeine varies hugely from person to person.

While caffeine is perhaps the most socially accepted psychoactive drug around, with an ability to increase alertness and aid energy release, especially from fats in exercise, it’s probably not the only or main substance in coffee linked to improved health.

Coffee is a rich source of potassium and is linked to lower blood pressure. Having said that, people with kidney disease may need to lay off the coffee - especially as many people add milk which increases the potassium content even more. What might also be a surprise is that a cup of coffee can contain as much as half a gram of fibre! The fibre found in coffee is different to the type of fibre we find in wholegrains, though - they are small soluble compounds known as ‘phenolics’.

These phenolics, along with caffeine, add to the bitter taste and, in the test-tube, are known to be powerful antioxidants. Unfortunately, the ability of these compounds to reduce the risk of heart disease, cancer and liver disease by neutralising up harmful ‘oxidising’ chemicals in our bodies is unlikely, as they are poorly absorbed. They could assist in helping the bacteria in our gut to maintain our health though. In addition, the small amounts that are taken into our bodies might help support our liver and other defences so they can be better at preventing disease.

Evidence for health benefits of coffee

So, coffee can be healthy, but is it as healthy as news stories say?

There might just be something in coffee which is helpful to health, but is it as good as some of the papers say? Recent headlines have claimed that up to 25 cups of coffee a day are safe for heart health and that coffee may be the secret to helping fight obesity, but is this true?

Firstly, the idea that up to 25 cups a day is good for our hearts was not a formal research paper but was a talk at a scientific meeting so much of the detail is hard to assess. However, when looking deeper into the research, the scientists grouped together everyone consuming 3 to 25 cups a day and only excluded those who drank more than 25 cups of coffee a day. So, although some people did drink two dozen cups of coffee a day, it’s more likely that most people had a far more typical 3 to 5 cups a day!

In addition, when the news reports stated heart health, it didn’t look at whether heart attacks were prevented, but how ‘bouncy’ blood vessels were in the coffee drinkers’ fingers. This is an indirect assessment of risk of heart health, but it’s not exactly the same thing so this looks to be a good example where the headlines make an impact by inflating both the number of cups and the potential health benefits of coffee.

Another recent coffee story suggested it could be a potential way of managing weight. The study investigated different types of body fat cells in the lab. This is because there is a special type of fat, called ‘brown adipose tissue’ found in people and more brown fat is found in naturally thinner people. Unfortunately, this study did not look at people who were overweight, nor did it look at changes in weight or if they actually burnt more calories! So, it didn’t really measure if coffee can help people lose weight at all. Once, again this was a news story that reported more than the actual research found out!

It’s quite possible that coffee could be healthy though. Many studies of large communities of people seem to show it can be healthy when drunk in moderation. It seems that people who drink 1 to 3 cups of coffee a day appear to have lower risk of heart disease, liver disease and developing Type 2 diabetes, than those drinking none or those drinking many more. It’s not all about coffee intake though as other lifestyle factors such as smoking or non-smoking and fruit and vegetable intakes have an impact on health risks too.

Is coffee healthy then?

The way coffee is made seems to have a big impact on how healthy it is. Different beans, ways of roasting and brewing can certainly vary the caffeine content. For most people it’s the milk, sugar and syrups, cream, sprinkles and extras that probably influence how healthy your coffee is. A black americano or instant coffee will only contain a handful of calories, whereas the largest salted caramel mocha can contain over 500 calories, a quarter of a woman’s energy needs for a day and more.