Scientists once believed that coffee was bad for your health – but it now seems that the drink may come with a number of benefits.

It’s a morning ritual that kick-starts the day for millions of us. Indeed, the joy of getting up and gulping down a hot cup of coffee cannot be underestimated. It can wake you up, drive you forward and help you to focus. In fact, some statistics suggest that 150 million Americans drink the beverage every day. But how many of us stop to consider the effect that a cup of joe might have on our bodies?

After all, coffee has been getting bad press for decades now. Since the 1970s, it’s been painted as an addictive stimulant, which can have a range of negative impacts on health. In particular, the consumption of the caffeine-rich beverage has been linked to higher instances of heart disease and cancer.

But it now seems that coffee might not be as dangerous for our health as we once thought. Indeed, some studies in recent years have explored the positive impact that the drink might have for us. And some scientists believe that the benefits of drinking coffee might even outweigh the negatives, which once gave the beverage its unhealthy reputation.

But first, let’s consider just why coffee has earned itself such a negative reputation. The answer is a complicated one, however, as the drink contains a heady mix of chemicals. Probably the most well-known of these substances is, of course, caffeine, which is a naturally occurring insecticide made by plants. It’s also a stimulant and a psychoactive substance.

Given that caffeine is completely legal and unregulated in most countries, it is the most widely used psychoactive drug on the planet. It’s found in tea leaves, cocoa beans, Kola nuts – which make cola – and coffee beans. And this abundance is part of the reason why there are quite so many caffeinated beverages around. Indeed, a 2014 study found that 85 percent of Americans consumed at least one drink containing caffeine each day.

And caffeine has some interesting effects on our biology. Indeed, the compound is sometimes included in pain-killing medications along with ibuprofen or paracetamol, in order to enhance their efficacy. It is also a key component of numerous energy drinks based on the fact that it helps to tackle drowsiness. The substance does this by blocking signals from the chemical adenosine in the brain, which would otherwise leave us feeling sleepy.

What’s more, caffeine has a direct impact on the nervous system, and it can help us to focus and to be more alert. However, too much caffeine can lead us to feel twitchy and anxious. It also boosts adrenaline – which kick-starts our “fight or flight” instincts. This can lead to high blood pressure and an erratic heartbeat.

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Because of all this, coffee can cause issues such as nervousness, irritability, restlessness, muscle tremors, insomnia and stomach upsets. Drinking too much could also be dangerous for those who already experience high blood pressure. And there are other medical conditions that make drinking coffee riskier as well. Of course, it can affect us all differently; and your genetic make-up also affects how well your body copes with coffee in your system.

For instance, pregnant women may want to think about reducing their caffeine intake. This is because, in rare instances, there is a link between coffee drinking and miscarriage. That said, other research suggests that expectant moms can drink a moderate amount of coffee without any risk to their unborn child.

That said, drinking too much coffee may also have a negative impact on fertility. It’s believed that women who consume five cups of coffee or more each day will find it harder to conceive through IVF. And it’s not just women trying for a family who should take note of their coffee intake.

Individuals who have to watch their cholesterol may also have issues after consuming some types of coffee. That’s because coffee beans contain a compound known as cafestol, which can boost low-density lipoprotein (LDL) cholesterol. However, paper filters can get rid of most of this compound. With that in mind, cafestol tends to be found in higher quantities in espressos and French press-brewed coffee.

A study in the Journal of the American Medical Association, from 2006, found that coffee could even add to the probability of nonfatal heart attacks. This is due to the fact that some people are genetically predisposed to metabolize caffeine less quickly. Giving up can also have negative consequences – those who quit caffeine completely can suffer from withdrawal symptoms including tiredness, inattentiveness and depression.

Other studies, meanwhile, have made links between coffee consumption and cancer. In 2008 experts said that drinking in excess of four cups per day increased a woman’s chances of breast cancer by almost two-thirds. The study also found that consuming a large amount of caffeine also boosted the threat of developing harder-to-treat tumors by 79 percent.

Some experts have also expressed concerns about acrylamide’s presence in coffee. This substance is also found in high-carb foods that come into contact with high temperatures – such as bread, potato chips, cereal and cake; it also forms when coffee beans are being roasted. And it’s something that we should perhaps be thinking more about.

That’s because there’s some evidence to suggest that acrylamide can increase the risk of cancer. When ingested, acrylamide can turn into epoxide glycidamide; and both of these substances are capable of altering and damaging human DNA. Of course, these kinds of changes can ultimately lead to cancer. But it’s not always that straightforward.

Indeed, when it comes to the connection between coffee and general cases of cancer, things aren’t so clear cut. That’s because the risk of developing cancers is really dependant on the amount of acrylamide consumed over a lifetime. If a person weighing around 175 pounds consumes under 208 micrograms of acrylamide per day then the evidence suggests that they shouldn’t have any higher risk than the baseline.

However, the same World Health Organisation (WHO) scientists who identified acrylamide as a likely carcinogen had something else to say. In fact, they concluded that there was no definitive proof that coffee could cause cancer. And in 2016 the WHO officially removed coffee from its log of potentially cancer-causing substances.

Similarly, breast cancer experts have proven to be sceptical about linking coffee to the disease. Liz Carroll, of U.K.-based charity Breast Cancer Care, called for “much more research” on the matter. Referring to the 2008 study, Carroll told The Daily Telegraph, “The results of this large study are very reassuring and suggest that for the majority of women, caffeine does not increase breast cancer risk.” And she was not alone in reaching these conclusions.

Commenting on the same study, Dr. Sarah Cant, of Breakthrough Breast Cancer, another U.K. charity, told The Daily Telegraph, “At this stage, [we] would not advise women to change their caffeine habits purely because of fears over breast cancer. We do know you can reduce your risk of developing breast cancer by maintaining a healthy weight, drinking less alcohol and exercising regularly.”

So not only are some of the studies linking coffee to ill health inconclusive, but there’s now research that suggests the exact opposite. In fact, some scientists believe that coffee is actually good for you. It may even increase the length of your life – and it can reportedly help to fight off some forms of cancer.

In 2017 a study actually found that those who drink coffee seemed to enjoy better health in general than those who didn’t. The findings, published in the BMJ, emerged from research at the U.K.’s University of Southampton. You see, in the study, scientists actually found that coffee drinkers were 17 percent less likely to suffer an early death than non-drinkers.

The study also found that those who drank coffee were 18 percent less likely to get cancer and 19 percent less likely to develop fatal heart disease. And elsewhere, research has linked coffee to a reduced incidence of early death and illnesses including Type 2 diabetes and Alzheimer’s.

And according to Southampton scientists, those who saw the greatest health benefits from coffee were those who drank in the region of three cups per day. Commenting on the study, Dr. Eliseo Guallar of Johns Hopkins Bloomberg School of Public Health, told Time, “I think now we can be reasonably reassured that, overall, coffee drinking is a safe habit.”

And there was more good news to be had in 2018. The National Cancer Institute in the U.K. suggested that people who drink coffee may have a reduced risk of early death. This was regardless of the kind of coffee they had, how much of the hot stuff they drank or whether they favored instant or decaf varieties.

The results came from the U.K. Biobank – an extensive study of people’s genes, carried out in Britain. More than 500,000 individuals had donated their blood and answered an in-depth survey on their health in order to take part. And the insights that the data gave into the effects of habitual coffee consumption were striking.

It was a team from the National Cancer Institute that decided to take a look at the details stored on coffee drinkers in the U.K. Biobank; they investigated what these individuals were drinking and in what quantities. They also took genetics into consideration, as this can have an impact on the way that a person metabolizes caffeine. After that, they explored the likelihood of death over the course of the ten-year study.

The researchers concluded that, regardless of the quantity of the drink or how it was prepared, coffee consumers were at an advantage. Indeed, they found that these individuals were more likely to survive the ten-year study period than those who didn’t drink the beverage. Perhaps surprisingly, even those who drank in excess of eight cups a day were more likely to survive than those who drank none.

Even so, experts say that there’s no real advantage in drinking more coffee than you usually would in order to reap the apparent health benefits of the drink. That’s because death rates didn’t appear to improve as more coffee was consumed on a daily basis. So it’s probably best to stick to an amount normal for your lifestyle.

Furthermore, the study conducted by the National Cancer Institute had some limitations. For instance, most of the volunteers in the U.K. Biobank are British – as might be expected. Because of this, though, their coffee-drinking habits differ from those in other countries around the world. For example, they tended to consume more instant coffee than is the norm elsewhere.

However, the National Cancer Institute team plans to take its study further, drilling down into the data to explore the impact of how the drink is prepared. By doing this, they hope to determine whether, say, drinking filtered coffee or pressed coffee results in different outcomes. This may help scientists to understand why unfiltered coffee has previously been linked to increases in bad cholesterol.

The National Cancer Institute findings weren’t the only source of good news for coffee drinkers, however. In the United States, coffee is believed to be the top source of antioxidants in the general diet. These chemical compounds help to combat everyday harm done to our DNA. Antioxidants can hence decrease inflammation, fight cancer and assist healthy liver function.

What’s more, coffee also contains other anti-inflammatory compounds. These can lower the threat of heart conditions and diseases of the liver, including cancer and cirrhosis. Anti-inflammatory compounds can also reduce the chances of individuals developing Alzheimer’s. You might be beginning to wonder if there’s anything that coffee can’t do for you.

Indeed, in 2010 a study was published by scientists from the University of Lisbon and the University of Coimbra. Strikingly, they found that coffee may prevent neural degeneration in the brain. As a result, drinking coffee could actually help to reduce a person’s chances of contracting conditions such as Parkinson’s and Alzheimer’s.

According to the study, the positive effects on neural degeneration only occurred when moderate amounts of caffeine were ingested, consistently and over the long term. Moderate consumption, meanwhile, was considered as being equal to four cups of coffee or less per day. However, those who worked on the study stressed that caffeine didn’t enhance mental faculties – it just stopped them from deteriorating.

Nevertheless, there are scientific findings to suggest that coffee can be of assistance when it comes to a number of other ailments. For example, it may assist people in their recovery from colon cancer. Furthermore, it may protect against other cancers, including those that affect the liver, skin, prostate and breast.

What’s more, it seems that drinking coffee can lower the risk of an individual developing Type 2 diabetes. In fact, the Diabetes Care journal published a review of 28 studies on the matter. They discovered that those who drank six cups a day actually saw a benefit; whether the coffee was caffeinated or not, these individuals saw their chances of getting Type 2 diabetes drop by some 30 percent.

In 2018, meanwhile, a study from the International Agency for Research on Cancer – based in Lyon, France – delivered more positive results for coffee lovers. It found that those who drank two or three coffees a day had healthier circulatory systems and livers. Furthermore, the researchers found that coffee drinkers had less inflammation than non-drinkers. And this study was pretty extraordinary.

Indeed, the research project had 500,000 participants living across 10 countries in Europe. The 16-year study, led by epidemiologist Marc Gunter, is believed to be the largest piece of research of its kind ever attempted. According to National Geographic, the study found that “higher coffee consumption was associated with a reduced risk of death from any cause.”

Now, previous studies had discovered links between coffee consumption and increased immunity to particular health problems. However, the study led by Gunter provided what are likely the most significant and far-reaching results so far – as well as impacts on a range of other conditions. As Gunter noted, “This digestive disease relationship, which was strongest for liver disease deaths, is particularly striking.” He now plans to break coffee down into its chemical constituents to learn even more.

With all this considered, coffee may be a far more benign beverage than we had previously thought. While too much caffeine can most certainly kill, it would take a huge quantity of some 20 servings or more, consumed simultaneously, to do so. So, all in all, these scientific findings are good news for coffee drinkers. Indeed, they can now appreciate the fact that their health shouldn’t necessarily suffer at all as a result of enjoying a good ’ol cup of joe.