Debates about coffee are everywhere. For many of us, coffee is a regular indulgence, whether it is a single cup every so often or four to five cups a day – but what is this doing to our health?
Well, it really depends on who you ask.
There are a lot of rumors about coffee, such as how it can stunt your growth or how drinking coffee at any time can affect your ability to sleep at night.
But, there is also growing evidence that coffee may actually offer health benefits.
So, how do the potential health benefits of coffee stack up? Is coffee good for you or does it ultimately do much more harm than good?
Our Love of Coffee
We are a culture that simply can’t get enough of coffee.
For example, in 2013, there were more than 7,000 Starbucks stores in the United States alone (1) and that doesn’t even count all of the other coffee stores out there. In fact, Americans consume around 400 million cups of coffee every single day and more than $4 billion dollars of coffee is imported into the United States each year (2).
That’s a lot of coffee to go through – and many of us can’t imagine going through the day without it. Despite the prevalence of energy drinks and soda on the market, even young adults are going back to coffee, with coffee consumption increasing in recent years (3).
At the same time, there has been a growing interest in gourmet coffee and coffee brewed from beans. In contrast, instant coffee has been taking a backseat. But, is this love healthy?
Most of us don’t really drink coffee because of health – yet, the drink actually does have some significant health benefits.
There are also many different ways to drink coffee and machines that can help you get the most out of it. The Coffee Maven is a great resource for that purpose, offering powerful buyers guides for coffee makers.
Health Benefits of Coffee
Coffee has a strong potential to contribute to weight loss through a few different mechanisms. Most people are probably aware of the first one, which is simply that coffee consumption can decrease appetite.
This is a particularly important role as many people trying to lose weight struggle with feeling hungry and craving food that their body doesn’t need.
Coffee is also a hot drink that takes time to consume.
This can also play a role in weight loss, because people don’t tend to look for other food while they are drinking coffee.
This means that people trying to lose weight can choose to drink coffee instead of having a snack.
Of course, this only works with coffee that is low in calories, which means some of the specialty coffee from Starbucks or coffee laden with cream and sugar wouldn’t have the same effect.
Another element of coffee and weight loss is that research has indicated that the polyphenols in coffee can increase energy metabolism and decrease the rate that body fat accumulates at (4). Coffee has also been linked to mobilizing fat from tissues, potentially making it easier to lose weight (5).
Theoretically, this means that drinking coffee may increase the rate that people lose weight and decrease the weight that they put on. While the effect might not be dramatic, it is pretty significant when you combine it with the other ways that coffee can help people lose weight.
Indeed, research has even indicated that people who drink coffee frequently tend to have a lower BMI (body mass index), waist circumference and a range of other factors compared to those who rarely drink coffee (6). The results of that particular study also indicated that coffee consumption could have positive impacts on the presence of many issues associated with metabolic syndrome, which is a group of conditions that act as risk factors for type 2 diabetes, stroke and coronary heart disease (7).
Coffee can make it easier to lose weight and can potentially increase metabolism and decrease appetite - helping people to lose weight
One of the most well-researched health benefits of coffee is its ability to decrease the risk of type 2 diabetes.
One study analyzed this across a sample of more than 100,000 individuals from several different studies. The authors of the study found that patients who increased their coffee consumption throughout the study period decreased their risk of type 2 diabetes while those who decreased their consumption of coffee actually increased their risk of type 2 diabetes (8).
The impact of coffee consumption on diabetes risk appears to be independent of caffeine, as people drinking both caffeinated and decaffeinated coffee saw a decrease in diabetes risk (9). The outcomes of the study can be seen below:
This graph is based on the data from the study and shows changes in the risk of type 2 diabetes compared to a baseline of 0 cups of coffee per day (so, not drinking coffee would be a relative risk of 1).
In fact, one study even found that drinking upwards of 12 cups of coffee a day resulted in a 67% lower risk of diabetes (10). Now, that is an extraordinary amount of coffee to drink every day and I don’t recommend it, nevertheless, it is a very interesting outcome. One potential reason for this mechanism is chlorogenic acid, which can significantly help to reduce blood sugar (11).
As I mentioned before, drinking coffee can also help to curb appetite, so this may be part of the reason why diabetes risk appears to decrease when increasing the number of cups per day.
Coffee is also significant for people who actually have diabetes. In particular, it can act to reduce the amount of carbohydrates stored and improve insulin sensitivity (12).
Research has consistently shown that coffee consumption can decrease the risk for type 2 diabetes
Not surprisingly, the consumption of coffee has been linked to improvements in mood. This impact of coffee is most obvious in the way that people’s moods often seem to be worse before they’ve had their first cup of coffee in the morning.
The reason for this is partly that coffee (specifically the caffeine in coffee) helps to make people more alert and reduce feelings of fatigue. This, in turn, boosts overall mood.
However, research studies have shown that this impact occurs with the supplementation of caffeine in general. This includes times where subjects are sleep deprived as well as times where they are normal and healthy.
A 2008 study considered the overall impacts of caffeine consumption on mood (and a range of other outcomes) by looking at the results of a selection of different studies. The authors of that study found caffeine consumption was consistently associated with improvements in mood, regardless of whether subjects were sleep deprived.
Additionally, the impacts of coffee on mood continued to be significant even for habitual users (13). This suggests that regular coffee drinkers never completely build up a tolerance for the positive impacts of coffee.
Research also indicates that drinking coffee regularly can act to significantly decrease the risk of suicide, specifically as the result of the caffeine consumption (14). It is likely that this outcome occurs through many of the same mechanisms through which coffee (and caffeine) is able to improve mood.
In a similar manner, caffeinated coffee has also been linked to a decrease in the risk of depression (15).
Coffee can improve mood and even reduce the risk of depression and suicide
Heart and Liver Disease
A persistent myth about coffee is that it increases the risk of heart disease or stroke.
This belief is largely based on early research, which used a research design that did not take all factors into account.
However, more recent results have called this myth into question.
Research also suggests that coffee provides some benefits in the case of liver disease.
One such benefit is that higher levels of coffee consumption have been linked to slower fibrogenesis progression in people with chronic and alcoholic liver disease (18).
There is also some indication that coffee consumption may help to protect people against the development of liver disease, but more research needs to be done to determine whether this is the case (19). Likewise, a meta-analysis indicated that coffee may reduce the risk of liver cirrhosis (20).
Despite myths about coffee being bad for the heart, it can actually decrease the risk of heart disease, stroke and also liver disease and liver cirrhosis
Now, you may have heard rumors that coffee can contribute to cancer development but this perspective is mostly just that, rumor. In fact, the World Health Organization recently removed coffee from its list of possible carcinogens (cancer-causing agents) (21) and research has failed to find a causal link between coffee and cancer (22, 23).
Instead, coffee may actually act to decrease cancer risk.
A study that followed 47,911 men from 1986 through to 2006 found that participants who drank more than six cups of coffee per day had a lower risk of prostate cancer (24). Interestingly, the outcome was found for both caffeinated and decaffeinated coffee, suggesting that the protective element came from other compounds in the coffee.
A study on 67,470 women over a 26 year period also found that coffee consumption decreased the risk of cancer, in this case, endometrial cancer (25).This study also differed in that it found that four or more cups of coffee per day were associated with a decrease in the risk of cancer.
However, the authors note that the addition of cream and sugar to coffee could offset any health benefits of coffee in relation to cancer risk.
Another study found that coffee consumption was able to significantly reduce the risk of death from liver cancer among a study group of more than 215,000 males and females (26).
Finally, a meta -analysis found that drinking more than 5 cups of coffee per day was associated with a reduced risk of colorectal cancer (27).
Coffee consumption has been linked to decreases in the risk of prostate, endometrial, colorectal and liver cancer
Most people associate coffee with being able to think better and more clearly, particularly if they were tired or sleep deprived beforehand.
This relationship is largely due to the caffeine in coffee, but coffee also plays a role in preventing damage to the brain – specifically related to Alzheimer’s disease and Parkinson’s disease.
In fact, coffee has even been associated with decreasing the risk of cognitive disorders in general (28).
Caffeinated coffee has been linked to improvements in Alzheimer’s disease and even as a way to reduce the risk of getting the disease.
This topic has been most commonly studied in mice, with one study finding that coffee offered some protection against the development of Alzheimer’s disease and the decrease in levels of amyloid-beta (a critical component of Alzheimer’s disease) (29).
A meta-analysis also supported the potential of coffee to reduce the risk of Alzheimer's disease, although it is clear that more work in the area is needed (30).
Another area where coffee can improve health is in relation to the development of Parkinson’s disease. A growing amount of research has indicated that drinking caffeinated beverages on a regular basis can significantly decrease the risk of developing Parkinson’s disease.
The image below shows the outcomes of one such study, which looked at the incidence of Parkinson’s disease in Japanese-American men.
This particular study considered outcomes from a 30 year follow-up and included 8,004 participants (31). Overall, higher levels of coffee consumption were associated with lower rates of Parkinson’s disease.
Another study found similar outcomes when looking at 6,710 males and females (32). However, in that study, the authors also found that other factors could influence how protective coffee consumption was against Parkinson’s disease. In particular, the authors found that the association between coffee consumption and decreased Parkinson’s disease risk was stronger in people who were overweight.
A third study considered 77,713 females and found similar outcomes (33). One key difference with that study was that the authors looked at caffeine itself rather than coffee consumption. This suggests that the protective effects of coffee are the result of caffeine rather than other components of coffee.
Coffee is a stimulant with the potential to improve brain function and provide protective benefits against Alzheimer's disease and Parkinson's disease
Overall, coffee consumption has been linked to a decreased risk of death.
For example, one study looked at coffee consumption of 400,000+ people who were somewhere between 50 and 71 years old when the study first began (34). Not only did the study find a significant negative association between coffee consumption and death overall, but also for a number of different specific causes of death.
The study design means that the data can only prove that a relationship exists, not that coffee directly caused the decreased risk of death. Nevertheless, the high number of participants and the solid experimental design overall suggests that the outcomes of the study are likely to be accurate. The graph below shows some of the key outcomes of the study and similar outcomes were seen with the individual causes of death.
This graph is interesting. It shows that the best outcomes in terms of risk of death were at between four and five cups of coffee per day.
After that point, the risk of death started to increase again, although it remained far below the original baseline. This could be an indication that six or more cups of coffee a day is harmful, or it might simply mean that people drinking this much coffee in a day also have unhealthy lifestyles in general.
Interestingly, another study indicated that a decrease in mortality because of coffee consumption occurred for caffeinated and decaffeinated coffee – suggesting that the caffeine is not the reason for a lower risk of death (35).
Even though the pattern here looks a little different, it still reinforces the idea that coffee consumption can decrease the risk of death. In this case, every group that consumed less than 5 cups of coffee per day had a lower risk of death than people who did not consume coffee.
As with the earlier study, this response was also dose-dependent. In this case, the people with the lowest risk of death were those consuming between 1 and 3 cups of coffee per day.
Despite the differences between the studies, this research does strongly support the idea that the people who consume coffee have a lower risk of death than those that do not (although, this is questionable for people who drink more than 5 cups per day).
There is also another interesting area to consider - the potential of coffee to promote longer telomeres (38).
Now, the term telomere refers to repeating sequences of DNA that are present at the end of chromosomes. Essentially, these act as caps on DNA, protecting the rest of your chromosomes and the essential information that those chromosomes provide (39).
Telomeres are so important because the process of DNA replication is not 100% complete. Instead, the ends of DNA cannot be effectively replicated. As such, the DNA in a chromosome will become shorter over time, as subsequent DNA replication shortens the telomeres.
Now, the process is entirely natural - but researchers have been looking for the connection between telomere length and the symptoms of aging.
One reason for this is that late in life, the telomeres become so short that they are no longer effective at preventing DNA damage.
In theory, if we can find ways to lengthen telomeres, it may be possible to 'turn back' the biological clock and help people to live longer. Indeed, research has supported the idea that short telomeres can contribute to a shorter life. Likewise, lifestyle factors can influence the length of our telomeres, which may be one reason why people with healthier lifestyles tend to live longer (40,41).
This field is still a fairly new one but one piece of recent research did find that coffee consumption was associated with longer telemeres in nurses (42), suggesting one possible mechanism for the connection between coffee and life length in the population as a whole.
Observational studies have linked coffee consumption to reduced risk of death
Other Health Benefits of Coffee
Research has also indicated that caffeine consumption can significantly reduce the risk of developing kidney stones (43) as well as gallstones (44,45). However, both of these areas have been the subject of a relatively limited amount of research, so the outcomes are far from conclusive.
Another relatively surprising outcome is that the consumption of caffeine can help to reduce the development of tinnitus in women. Tinnitus is a steady ringing in a person’s ear and for this particular study most of the caffeine consumed came from coffee (46).
This particular piece of research was a prospective study. As such, it offered some evidence that a negative relationship between caffeine consumption and tinnitus exists, but more research on the topic is needed.
A final health benefit that has been associated with coffee is its ability to prevent breaks in DNA, helping to maintain the integrity of DNA (47).
Other health benefits that have been linked to coffee consumption include protection against kidney stones, gallstones, tinnitus and breaks in DNA
There is growing recognition that antioxidants are associated with many health benefits. Specifically, antioxidants are molecules that prevent other compounds from being oxidized.
Now, within the body, a degree of oxidation is important for chemical reactions, but too much oxidation can be harmful. One major issue is chemicals known as free radicals.
Free radicals are highly reactive because they are missing an electron in their outer shell. This means that the free radical will try to get an electron from other molecules in the body.
In doing so, free radicals can cause significant cell damage, contributing to many health complications and aging in general. Despite their importance, most people don’t get enough antioxidants into their diet.
There are a few different ways of calculating antioxidant levels in food, one of which is the ORAC, which stands for Oxygen Radical Absorbance Capacity, which the USDA used to promote (48). The antioxidant value of foods is far from the only indicator of their health benefits, and looking at these levels should still be done with some caution.
Nevertheless, high levels of antioxidants can be a strong indication that a particular food offers some health benefits.
So, what about coffee?
Antioxidant Levels in Coffee
In general, the ORAC value of coffee tends to range from 15,000 to 17,000 depending on the specific type of coffee and how long it was brewed for. In the grand scheme of things this isn’t a lot, as you can see from the graph below.
Even though the amount of antioxidants in coffee is relatively low compared to other high sources of antioxidants – it is still a significant amount.
Additionally, most Americans actually get most of their antioxidants from coffee. In fact, the majority of antioxidants in the diet come from beverages in general, including coffee, wine, fruit juices and tea (49).
This is because of consumption level. Many of the high antioxidant foods are things like spices, berries or dark chocolate. Even if you included all of these in your diet, you would probably include them in relatively small amounts.
For example, people tend to use a pinch or a teaspoon of spices or a couple of squares of dark chocolate a day. In comparison, you might have three or four cups of coffee in a day, and many people have more.
While people who are intentionally focusing on antioxidants might be taking in more from other sources, the vast majority of people in the United States get most of their antioxidants from beverages, with coffee being the leading candidate. Because of this, many of the health benefits of coffee stem from the antioxidants in it.
The term antioxidants actually refers to a large group of different chemicals that perform a similar role.
However, there is actually a lot of variation among antioxidants, and different compounds do different things.
For coffee, one significant group of antioxidants is the hydroxycinnamic acids.
This group of compounds is highly potent antioxidants and they are also polyphenols. This is important, because polyphenols have also been linked to a number of health benefits beyond their antioxidant abilities (50).
Because of this, it is important to include polyphenols (like those found in coffee) in the diet, as well as just antioxidants.
Coffee is a highly important source of antioxidants, which have the potential to improve health overall
All Coffee is Not Equal
One of the challenges with coffee is that there are so many different varieties out there.
This can make it particularly difficult to figure out what type of coffee will offer the best health benefits – especially as you also have to look for coffee that you actually like drinking in the first place.
How You Make It
The health benefits of coffee come from the coffee itself and the many different chemicals in it. This is something that you have to consider when you are making coffee.
In particular, many people choose to add things to their coffee when they make it, such as milk, sugar or even cream. Other people also go for the specialty coffee that places like Starbucks offer.
When you do this, you end up diluting the actual coffee in your drink, in favor of additions that are not as good for your health.
For example, in this image you can see how black coffee is relatively low in calories, regardless of source, while specialty coffees from Starbucks are high in calories and coffee with milk and sugar is somewhere in the middle.
While the calories involved in adding milk and sugar to coffee are still relatively low (especially if you pick low-fat milk), you do still need to be aware of these calories. If you are having one cup of coffee a day, then they probably won’t matter too much, but if you are having three or more, then you do want to carefully consider what you are taking in.
Ultimately, the nutritional benefits of coffee aren’t going to mean that much if you are consuming a lot of sugars and fat through your coffee.
So, this option won’t help your health whatsoever.
Single Serve Cups
Those little single serve cups for coffee has been developing into a pretty major trend and it looks like they are here to stay.
The concept of these cups is that they allow you to brew a single cup of coffee without hassle or mess – theoretically resulting in better quality and consistency overall.
Essentially, the cups are small containers that contain a coffee filter and ground coffee beans. When used in the brewer, the cups produce a single cup of coffee.
This type of single serve cup has become very popular, with a large number of brands producing them. For many people, these cups are desirable because they make it much easier to make coffee for a single person, and make it possible to try many different flavors without having to make full brews of each.
But… what does this mean for health?
For the most part, these single serve cups are the same as filtered coffee, particularly as they already contain the filter within them. This makes them a healthy choice for coffee consumption because using a filter tends to be better for health overall (51).
Nevertheless, cups like this are the source of major controversy. After all, there is a lot of waste that goes into them, especially as most people use each cup just once and normally you can only ever get away with using them twice.
Furthermore, the cups are made out of plastic, which certainly isn't good for the environment.
There is some call for the development of new materials, which would make the cups more sustainable and allow them to be recycled (52). However, whether or not this will actually happen remains to be seen.
However, not everyone agrees that the cups are as wasteful as they seem. For one thing, they help people to actually brew the amount of coffee they are going to drink, which reduces waste. In fact, people do normally overestimate the amount of coffee they need and end up throwing some out.
Likewise, the small cups are very efficient, which further reduces waste.
Now, reducing waste in this way is actually a very important advantage because coffee is a water-intensive crop.
So, using cups like these does help to reduce the amount of water that is wasted (and also the amount that you use yourself).
One way around some of these issues is to pick a reusable cup and fill it with grounds yourself.
These cups tend to be washable.
In doing so, you would lesson the impacts of packaging on the environment but you may end up using more water and perhaps wasting more coffee.
To be honest, I suspect that many people probably wouldn't find that option appealing anyway - as it does somewhat take away from the convenience factor of the cups.
So, at the end of the day, single serve cups are completely fine if you want the health benefits from coffee but the environmental impact of the cups is more complex. Ultimately, whether or not you choose to use them is going to be based on your own personal perspectives and priorities.
Not surprisingly, the type of roast of your coffee beans can potentially have health impacts. However, there is a lot of mixed information out there on the topic.
For example, some people argue that dark roast coffee is bad for you and that you should stick to light roast coffee.
The argument for this perspective has to do with the chemicals in coffee. Dark roast coffee is coffee that has been roasted longer.
However, the roasting process can potentially have impacts on many of the compounds in coffee, which may mean that dark roast coffee has fewer health benefits than light roast.
But, there are advocates for dark roast coffee too. In particular, dark coffee is easier on the stomach than light roast coffee. The reason for this is the production of a chemical that helps to decrease how much stomach acid is produced (53).
Additionally, research has also shown that dark roast coffee is more effective at achieving some health benefits, including the reduction of body weight and improvement of glutathione and vitamin E concentrations (54).
This does suggest that overall dark roast coffee offers more health benefits than light roast.
Despite this, at the end of the day, which you should choose largely comes down to personal preference. There is quite a bit of taste difference between dark and light roast, and many people find that they prefer one type over the other. In terms of health, it is worth remembering that many of the health benefits of coffee come from caffeine and that is relatively consistent across the different roasts.
The way that you make your coffee may influence the health benefits you get from it
How Does Coffee Improve Health?
Like it or not, many (but not all) of the health benefits of coffee are associated with caffeine.
Caffeine is a fat-soluble chemical and this gives it the ability to pass the blood-brain barrier and enter into the central nervous system. This lets it get into cells very quickly. Many of the effects of caffeine come from blocking a chemical known as adenosine
Adenosine is a neurotransmitter and it impacts a large number of different functions throughout the body. In particular, one thing that adenosine does is make people feel sleepy or tired. By blocking adenosine, caffeine helps people to stay awake longer and to be more alert while they are awake.
But this is only one impact of blocking adenosine. By doing this, caffeine also affects a large number of other neurotransmitters.
One such neurotransmitter is dopamine. By increasing the levels of dopamine, caffeine has the ability to improve mood and there is also the potential for long-term benefits through the protection of brain cells from degeneration (55)
Caffeine can also help people with depression by increasing serotonin levels. This process can also help to make people more alert and can help to stop migraines. These are only some of the neurotransmitters that caffeine affects.
In reality, we still do not fully understand all of the mechanisms associated with caffeine and its effect on the body. However, two things are clear in relation to caffeine and neurotransmitters.
First, caffeine can cause an increase in production or update of a number of neurotransmitters – a process that can increase both physical and mental performance. Second, caffeine acts to regulate the way that different neurotransmitters are balanced – a process that can help to reduce pain, reduce appetite, improve mood and potentially offer some protection for brain cells.
Research also indicates that caffeine has the ability to create positive changes in gene expression, including potentially adaptive changes. These include changes that may help to protect neurons (56).
Aroma and Other Compounds
Coffee is a complex drink.
While caffeine does play a strong role in the health benefits that coffee offers, it isn’t the only source of health benefits. In fact, more than 800 different aromatic elements alone have been discovered in coffee and it is likely that more will be discovered in the future (57).
This makes it challenging to isolate specific components of coffee and associate them with specific health benefits. However, the aromatic compounds in coffee are likely to play some role in health.
The reason for this is that the aroma of coffee can offer some health benefits even when people don’t actually drink the coffee. Just the smell of coffee alone can help increase alertness, particularly following sleep deprivation (58).
This research is still in relatively early stages, but just about any coffee drinker will tell you that the aroma of coffee – particularly from freshly ground beans – certainly has some effects.
Coffee can improve health through the action of caffeine on neurotransmitters and the role of aromatic compounds
Caffeine and Coffee
Caffeine is one of the more significant components of coffee. After all, many people drink coffee largely for the caffeine fix, particularly first thing in the morning.
Caffeine also has a pretty bad name. After all, too much caffeine can have all sorts of negative effects, such as insomnia, irritability, restlessness, anxiety and heartburn.
However, caffeine is actually important, particularly in the right amounts. Clearly, overdosing on caffeine isn’t going to offer significant health advantages, but having some through coffee can actually improve health.
Is Caffeine Addictive?
People are often concerned about caffeine being addictive. This is true to a degree, but it is important to note that coffee is not addictive in the same way that drugs or alcohol are. With caffeine, a level of addiction occurs because caffeine is a stimulant, making people feel more alert and engaged.
If you drink coffee regularly then start to go without it, you will feel some symptoms of withdrawal. In fact, one study found that high caffeine consumers performed poorly when they went without caffeine, yet low caffeine consumers performed at around the same level regardless of whether they had caffeine at the time or not (59).
This study showed that caffeine withdrawal did result in some detrimental effects – such as lower levels of mental alertness and poorer reaction time.
It also showed that caffeine’s effect on sleepiness and mental performance was lower for those who took caffeine regularly, suggesting a developed tolerance.
So, the study does indicate that people who have a lot of caffeine will experience some withdrawal effects – but that is to be expected. There were some interesting things about the study.
One was that caffeine did improve performance in both groups of participants. The second was that the other group of participants was considered the no-low caffeine consumption group, and had less than 40mg of caffeine per day. This group didn’t experience any of the withdrawal symptoms, suggesting that having a small amount of caffeine in a day is not strongly addictive.
Health Benefits of Decaffeinated Coffee
So, what about decaffeinated coffee? People normally drink decaffeinated coffee because they can’t have caffeine or they don’t want to.
Often this is the result of a medical condition, but sometimes it is a lifestyle choice. It’s certainly true that decaffeinated coffee doesn’t offer as many health benefits as coffee with caffeine.
After all, the caffeine in coffee does play a role in how coffee influences health.
However, caffeine is not the only healthy element of coffee. Some of the health benefits that we have discussed in this article go beyond caffeine, such as decreased risk of type 2 diabetes and decreased cancer risk.
Additionally, there may be many more health benefits associated with the aromatic compounds of coffee than we currently know. It’s also important to note that decaffeinated coffee does still have some caffeine in it, just not very much.
How much caffeine is present in decaffeinated coffee really depends on the brand, but one study found levels of 8.6 mg to 12.9 mg (60).
This isn’t a whole lot, but if you are drinking multiple cups of decaf coffee a day, you might find your dose getting close to the caffeine in a normal cup of coffee.
Research has also indicated that as low as 10 mg of caffeine can be enough to cause reactions in people who are sensitive to caffeine (61). This doesn’t mean that you should avoid decaffeinated coffee if you are supposed to be dropping caffeine in your diet.
However, you should be aware of the caffeine that you are likely to be ingesting and base how many cups of coffee you have around that.
Caffeine is associated with many of the health benefits of coffee – so it’s not surprising that many people choose to supplement with caffeine instead of actually drinking coffee. Most of the time you see these supplements in the form of ‘stay awake’ pills, which seem to be strongly marketed towards busy people and students.
It might seem like a good approach to get caffeine into your diet this way, but it has its limitations. Caffeine is associated with many of the health benefits of coffee, but not all of them.
By taking caffeine independently, you end up missing out on some of the other key benefits associated with coffee. Additionally, caffeine supplements frequently come in doses of around 200mg, which is roughly twice what is in a cup of coffee. This makes it very easy to have too much caffeine, particularly as taking a pill is easy and fast to do.
Because of this, you are much more likely to become dependent on caffeine through taking caffeine supplements than you would through drinking coffee.
How Much is Too Much?
Caffeine really is a tricky thing. Nowadays, people end up getting caffeine from so many different sources, including soda, energy drinks, coffee and even some foods.
The graph below shows the average level of caffeine in a selected range of products (mainly drinks) based on their common serving sizes.
Doctors frequently refer to moderate caffeine consumption as somewhere between 300 to 400 mg of caffeine per day.
What this means in practice really depends on the type of coffee you are drinking, but a very general estimate is that an 8 oz cup of coffee typically contains somewhere around 90 mg of caffeine. In reality, we still don’t fully understand all the mechanisms that caffeine has in the body, which makes it difficult to know all the positive and negative impacts of coffee.
However, it is clear that there is no set size for a healthy dose of caffeine. For some people, 300 – 400 mg of caffeine per day is no big deal, and they could easily have more. For others, even 300 mg of caffeine could give them symptoms of excess caffeine, including a rapid heartbeat and nausea. Part of this comes from how much caffeine people are used to. People who drink caffeine regularly will tend to have more of a tolerance than those who do not.
However, that’s not the only factor.
Some people simply metabolize caffeine faster, while others seem to be much more sensitive to even a little caffeine. So, when you are looking at how much caffeine you should be having it’s good to stop and look at your own body and how you react to coffee.
Many health benefits of coffee come from the caffeine but some are present in decaffeinated coffee too
Potential Negative Effects of Coffee
The focus of the discussion in this post is on the health benefits of coffee. Nevertheless, coffee is a complex drink and there is some potential for negative consequences on health.
However, these are not as bad as they seem and in most cases, negative health impacts are only relevant to a small group of people. For the vast majority of people, consuming coffee in moderation is not going to have any significant negative impacts on health – and is actually likely to improve health.
People are often worried about coffee causing dehydration. After all, coffee does tend to induce thirst, particularly if you don’t drink it all that often. The argument behind this is that coffee (and other drinks with caffeine) acts as a diuretic, increasing the amount of water that the body loses.
The theoretical basis for this perspective is that caffeine increases the amount of blood flow to the kidneys while also acting to prevent the reabsorption of magnesium, calcium and sodium. In doing so, caffeine can potentially result in more water being expelled.
However, actual studies on this behavior in humans with realistic levels of caffeine have been limited.
A meta-analysis of the relatively few studies on the topic found that high levels of caffeine consumption could result in higher water output, particularly when participants had been deprived of caffeine for days prior to the study.
However, for people with a low-moderate caffeine intake, there were no significant impacts. For this particular study low-moderate intake was between 1.4 to 6 mg of caffeine per kilogram of bodyweight (62).
So, if you do drink large amounts of coffee in a given day (say upwards of 4 cups), dehydration is something to be aware of, and you may want to increase your water intake as a consequence.
However, for many people, coffee is also a source of water – particularly if you don’t add much else to it.
At the end of the day, any dehydration effects of coffee aren’t really going to harm your overall health. Instead, this effect simply means that you have to be aware of the potential for caffeine to act as a diuretic and adjust how much water you drink.
One area of concern about coffee is the presence of mycotoxins.
Mycotoxins are a collection of toxic chemicals that are produced from mold – mold that can grow in crops that we eat, including coffee beans (63). These toxins are a cause for concern, because consumers often will not know that they are there, yet the toxins can have very strong negative impacts on health.
It is true that mycotoxins and even molds can sometimes be found in coffee beans. However, it’s important to understand that when this does occur, the amount of the toxin or mold present is very small. After all, there are a lot of regulations surrounding the presence of mycotoxins in food (64).
Furthermore, the danger from these toxins and from mold in food is dose-specific. This means that if you eat too much of them, you may get sick, but a little amount won’t do you any harm at all.
The amounts that are present in coffee are much lower than the safety limits, so they’re not a threat to human health – regardless of how much coffee you drink. Most of us don’t like the idea of ingesting any toxins or molds at all, but really this is unavoidable.
The vast majority of food that is produced can be contaminated with at least one mycotoxin and many people would even test positive for it if their blood was tested (65).
However, this really isn’t a big deal.
Through food and through activities people are constantly taking in small amounts of toxins and other undesirable things – but the amounts are simply too small to matter.
For example, one study found that even if people drink 4 cups of coffee per day, they would only reach about 2% of the safety limit for the mycotoxin Ochratoxin A (one of the more common mycotoxins in coffee) (66).
This leaves a pretty big margin for safety.
Additionally, the producers of coffee are already aware of molds and mycotoxins and their potential to do harm. As such, many coffee producers already take steps to minimize any risk in their products.
If you really do want to minimize your mycotoxin levels as much as possible, then it would be best to choose caffeinated, ground coffee as this has lower levels of mycotoxin overall. However, regardless of the type you choose, the levels really are too small to even be significant (67).
Coffee and Lifestyle
One major issue with coffee is that it is often used as a way to support a bad lifestyle. In particular, coffee offers a significant boost of energy, which is why so many people have it first thing in the morning. It can also be powerful for de-stressing.
However, coffee can easily become a ‘quick fix’ to issues like stress and being tired, and this means that people tend not to actually look for solutions.
For example, I have known many people who use coffee to keep them going in the day, often foregoing good food, exercise and sleep because they are trying to squeeze as much as possible into a single day.
This isn’t a good practice and it ends up creating a very unhealthy and very stressful lifestyle. Coffee is never going to offer many health benefits if it is simply being used as a way of supplementing an unhealthy lifestyle.
However, this doesn’t mean that coffee itself is unhealthy.
If you do have this type of lifestyle it would be best to start to look for ways to slow down and lower your stress levels. This includes actually getting enough sleep, eating good food and moving about more.
In general, the right way to drink coffee is as a treat and something you take your time to enjoy. This includes being aware of the impacts that coffee (and caffeine) has on your body and taking these into account.
Likewise, you should base how much coffee you drink on your own body and how it reacts to the coffee, not on how much caffeine other people are able to drink. Your body will give you indicators of when you have had too much coffee, often in the form of jitteriness or the inability to sleep at night.
The potential negative impacts of coffee are relatively few and are largely irrelevant when compared with a healthy lifestyle
Getting the Most out of Coffee
If you’re going to drink coffee, it makes sense to get as many health benefits as possible from it. As we already discussed, adding sugar, milk and cream to your coffee can often be detrimental, particularly if you are having multiple cups of coffee each day.
However, this doesn’t mean that you have to have your coffee plain. There are some things that you can add to your coffee that can potentially help to improve your health.
One example is the spice cinnamon, which has a whole range of health benefits and can also add quite a nice flavor to your coffee. Another option is to add a square of dark chocolate or even some cocoa into your coffee (avoid any that is processed with alkali).
It might be surprising, but full fat cream, milk or grass-fed butter can also be a good option. However, in these cases, you need to be very aware of the calories you are consuming and take these into account.
How Much Should You Drink?
One of the key questions about coffee and health is how much you should drink to see health effects. Many people are concerned that drinking too much coffee would have negative impacts on their health, while drinking too little would mean that they miss out.
However, many of the research studies that we have discussed found health benefits with large amounts of coffee, as much as six cups of coffee per day. This suggests that there isn’t really an upper limit to how much coffee you can drink to get health benefits.
Nevertheless, when it comes to coffee, you do need to take into account its effects on your body. Everyone handles caffeine and coffee differently, so you need to be aware of your own personal limits.
Additionally, you need to consider how your coffee influences the calories you are taking in.
For example, if you are having four cups of coffee a day, all with added milk and sugar, then the additional calories in your diet can be significant. This is particularly concerning for anyone trying to lose weight.
Storing and Reheating Coffee
Some of the components in coffee are relatively unstable. Because of this, if coffee is kept hot its flavor decreases rapidly as the chemicals break down.
This also means that the health benefits of the coffee decrease. Ideally, you should drink coffee as soon as possible after it is brewed to make sure you get the best flavor and the most health benefits from it.
You will also find that reheated coffee ends up with a ‘muddy’ flavor as even more compounds are destroyed during the reheating process.
This means that you shouldn’t ever try to reheat coffee – because the end product will taste bad and it won’t have the same health benefits.
However, it is possible to store brewed coffee at room temperature without the compounds significantly deteriorating, but only if the coffee is stored in an airtight container.
If you have brewed coffee at room temperature without using an airtight container, then its chemicals will tend to deteriorate.
But what about coffee beans and ground coffee?
Despite popular belief, you shouldn’t freeze or refrigerate coffee. Coffee is porous, which lets it absorb flavors well.
If you keep coffee in the fridge or the freezer, then the coffee has the chance to absorb flavors from other foods as well as the moisture.
If you absolutely have to store coffee in the freezer (like when you buy it in bulk), make sure you store it in air tight freezer bags and don’t try to freeze any coffee more than once. The absolute best way to store and use coffee is to buy it as whole beans and grind it right before using. As soon as coffee is ground some of the flavor is released and ground coffee will always go stale faster.
When you are storing your beans, store them in an air-tight container in a dark place. If you have to buy pre-ground coffee, try for coffee in a vacuum sealed bag. Coffee in these types of bags does tend to stay fresh longer, but the coffee was still sitting around before it was bagged, so it will never taste as fresh as freshly ground coffee.
Whether it is ground or still as beans, coffee should be stored in an airtight container, in a dark place and at a stable temperature. This environment helps the coffee to stay fresh for longer and helps to make sure that the health benefits of coffee remain intact.
The health benefits of coffee can be improved based on how the coffee is stored and what else you put in your drink
In general, there are four steps to making coffee drinkable. These are:
- Separating the coffee from the grounds
This makes it challenging to understand how to get the most out of coffee, because each step has the potential to remove some of the health benefits.
So, let’s go through them.
When you buy beans, they will be already roasted, so this isn’t an area you have to worry too much about. However, the roasting process does have a significant impact on the coffee and even on the health benefits of coffee.
One element of this is chlorogenic acid.
This is a polyphenol and it has been linked to many of the health benefits of coffee, including a reduction in risk for cardiovascular disease and a decrease in blood glucose (68).
The problem with this is that a lot of the chlorogenic acid in coffee gets destroyed during the roasting process. Because of this, there has been an emphasis on green coffee beans, which are basically unroasted beans.
These beans don’t go through the roasting process and this means that they have much higher levels of chlorogenic acid. However, you can’t make coffee out of the beans, so they tend to be taken as a supplement. There are some potential health benefits to doing this, but drinking coffee still tends to be better.
The problem with supplementing with green bean extract is that you are focusing on a single chemical in coffee and emphasizing this. That approach completely ignores all of the other health benefits associated with coffee, including the ones that are connected to the roasting process.
Sometimes when you buy coffee from the grocery store it will already be ground, but other times you may buy the beans and grind them yourself. The grinding method of coffee is important because it affects how you can brew the coffee.
For example, one approach to grinding creates very fine coffee dust. This works well for drip coffee makers but it is no good for French Presses or drip coffee machines.
With coffee, the brewing process is probably where you see the most variation. Four general approaches to brewing are used:
- Boiling (or decotation)
- Steeping (or infusion)
- Gravitational feed (used in drip brewers and percolation)
- Pressurized percolation (e.g. espresso)
How the coffee is separated from the grounds really depends on the brewing process that you are using.
For example, many automatic coffee machines both brew the coffee and separate it from the beans with little human assistance, and may even grind the beans as well.
For health reasons, it is normally better to go with filtered coffee if at all possible, and I’ll explain why in a little bit.
Health Impacts of the Methods
For the most part, the method that a person uses to make coffee is based on their own personal preferences and possibly the way that they were first introduced to coffee.
However, there are actually health impacts of the way that coffee is made. Coffee contains cafestol, which is a chemical that acts to stimulate levels of LDL cholesterol. This is a major issue because LDL cholesterol is associated with a number of health issues.
It is important to note that this strongly depends on the way that the coffee is made to begin with. Cafestol is in the oily component of coffee, which means that if you use a filter, the cafestol is left in the filter, so you don’t drink it.
Research has even indicated that drinking filtered coffee does not have any impact on lipid levels in the bloodstream, while drinking boiled coffee does have an impact (69). This means that the level of cafestol is higher when coffee is made without a filter, such as using the French press approach or boiling coffee.
So, to get the most health benefits out of coffee, you really do need to focus on drinking coffee that is filtered rather than coffee that isn’t.
While we’re on the topic though – I do want to point out that the single-serve coffees that you can get nowadays do actually have filters in them. By this, I mean the little cups that are used in Keurig machines and similar products. If you are drinking coffee from machines like that, then you don’t have anything to worry about.
Even if you do drink other types of coffee, it is likely that the health benefits of coffee still outweigh any potential negative impacts (70).
Oh, and while we’re on the topic of filters, do remember to actually wash your filter after every use.
Having clean and dry equipment is essential to making any good food or drink, and that includes making coffee.
The process of filtering is important for getting the health benefits of coffee
Coffee and Genetics
Genetics has actually made the study of coffee pretty challenging. A lot of research has gone into looking at what impact both coffee and caffeine have on people, such as cognition, mood, physical performance and even preventing gallstones.
However, a major issue has been that people simply do not respond to coffee in the same way.
For some people, drinking large amounts of coffee every day appears to have very little negative impact, while other people struggle with even one or two cups.
Recent research indicates that one element of this is genetics. Specifically, eight different components of the genetic code have been identified that are associated with the level of coffee consumption.
These genetic components indicate the presence of a molecular reason why people vary so significantly in their reactions to coffee. Additionally, the outcomes of the study indicated that caffeine may play a strong role in the development of coffee drinking as a habit (71).
Our genes may play a role in how we respond to coffee
Common Questions about Coffee
Is Organic Coffee Healthier?
In the coffee market, there are a lot of options for both organic and non-organic coffee. Some people do argue that organic coffee is better and even that it has a lower risk for mycotoxins.
One reason why this might be the case is that organic coffee growers often spend more time inspecting coffee plants and the coffee beans also end up being chemical free.
In contrast, non-organic coffee tends to be heavily treated with chemicals. In theory, organic coffee is also better for the environment. This means that people often choose organic coffee for environmental reasons rather than out of concern for their own health.
There isn’t much evidence suggesting that organic coffee is better for health and ultimately any difference would largely come down to the individual companies and brands being considered rather than just organic versus non-organic.
However, it is true that organic coffee tends to involve fewer chemicals throughout the production process.
This might be desirable if you are willing to pay the extra cost normally associated with organic coffee.
Nevertheless, it is important to note that organic farmers can still use some natural pesticides (72).
This topic is actually a controversial one and is a little bit ironic. Basically, the term natural refers to pesticides that have been derived from nature (similar to natural sweeteners) (73).
The concept plays into the myth that natural products are better for health than artificial ones. In reality, natural is better sometimes but sometimes it simply isn't. For the most part, our bodies can't tell the difference between a naturally-derived and an artificially derived compound. This means that natural products certainly can still be bad for your health.
In some cases, this even means that some organic coffee may use more pesticides than coffee that isn't organic. The main difference is simply in the type of pesticides.
Now, this isn't an area that has been researched in much depth but there is a good chance that some organic pesticides are as bad for health as artificial ones. In some cases, they may even be worse.
Regardless of whether you choose organic or non-organic coffee, it's important to note that coffee goes through intensive chemical treatment. One estimate suggests that around 250 pounds of chemical fertilizers are used per acre for non-organic coffee (74). While less chemicals tend to be used for organic coffee, organic options are far from chemical-free.
However, there is some good news.
Coffee beans go through high heat as they are roasted, which serves to burn off any residue left behind by the chemicals (75). As such, even non-organic coffee ends up being fairly free from chemicals (76,77).
Personally, I would still recommend organic coffee as a healthier option, simply because there is a lower chance that there will be harmful chemicals present. Likewise, organic coffee may be better for the environment and for the people who work in the fields.
Nevertheless, organic coffee certainly isn't as safe, or as chemical-free, as the name implies.
If you are interested in organic coffee, then there really are a lot of options out there.
It is still worth taking the time to read labels and find out a bit about the company behind the product though. Just because coffee is organic doesn’t necessarily mean that it is better than anything else out there.
Likewise, there is going to be variation in the approaches that companies use, so some brands of organic coffee are probably going to be healthier than others.
Why Do People Say Coffee Is Unhealthy?
There certainly are a lot of people out there that claim coffee is unhealthy – but this doesn’t actually mean that it is. There are a few different reasons why so many people believe this.
One reason is simply that they were told coffee is unhealthy.
In many cases, people base their behaviors and their beliefs off things that they learn, often from other people.
This can be an issue when the things that they learn aren’t correct.
In the case of coffee, there has been a lot of rhetoric around the idea that it is unhealthy. So, many people end up feeling that coffee is unhealthy, even though they don’t have any proof.
A second reason is the caffeine.
Some people find caffeine a little scary because it is mildly addictive and can have some pretty significant effects if you have too much. Additionally, some people are also highly sensitive to caffeine and find that even a little coffee has serious impacts. These people are often the ones that claim coffee is bad for them, but that doesn’t really mean that coffee is for everyone.
A third reason is research design.
Scientists often focus on understanding the relationship between two variables, like whether coffee contributes to increased cardiovascular disease or to a higher risk of death. The problem is that studies can be difficult to design. In terms of data collection, one of the best types of studies to do is a large-scale observational study.
This type of study involves obtaining data from many different people on many different topics.
For example, an observational study might look at different aspects of people’s health and behavior, including whether they smoked, how much coffee they drink, whether they have diabetes, what their weight is and many other things.
This might go on for a number of years, resulting in a huge amount of data. Some studies track people for more than 20 years, giving them the chance to look at whether any of the study participants died.
The end result of this type of study is a very large and comprehensive set of data. Researchers can then take this data and start to analyze it.
This is where problems start to occur.
Because this type of study is observational in nature, it can’t test for cause and effect. So, the study can’t say that drinking coffee increased risk from cardiovascular disease. Instead, it would have to say that there was a relationship between coffee consumption and cardiovascular disease.
But, the presence of a relationship doesn’t actually mean cause an effect.
In the case of coffee, observational studies did find a relationship between coffee consumption and some poor health outcomes. This may be partly why so many people feel that coffee is bad for your health.
However, while there was a relationship, it wasn’t actually coffee consumption that was driving the relationship. This is actually an issue that pops up in many different studies.
Many people who drink a lot of coffee do so as part of an unhealthy lifestyle. For example, they might be less likely to eat correctly or exercise enough, and might also be more likely to have a highly stressful life.
This is particularly true because many people drink coffee for the caffeine, especially when they are struggling with stress or low energy levels.
I’m not saying that everyone does this – far from it.
But, because many people do use coffee as part of a bad lifestyle, the outcomes of the research imply that coffee actually causes poor health – even when it is the lifestyle that actually does this.
More recent research has been able to correct this issue and separate out the effects of lifestyle and coffee consumption, and we have discussed many pieces of this research as part of this article.
Does Bean Quality Matter?
As with any product, getting higher quality is likely to result in more health benefits. In the case of coffee, the freshness of the product tends to be much more relevant than the quality of the bean – as is how the coffee is stored.
There have been a large number of scientific studies on the health benefits of coffee and of caffeine. These studies have varied in many elements, including in the type of coffee beans used.
As such, coffee is associated with significant health benefits regardless of the type of bean that is used. Organic coffee beans are an option, but limited research has gone into whether these are any better for health.
Perhaps the biggest difference between organic and non-organic coffee beans is simply that organic beans involve fewer chemicals, which could potentially contribute to improved health outcomes.
Coffee might seem like an unhealthy habit, but really it is a habit that offers many different potential health benefits. The antioxidants in coffee alone make drinking coffee worthwhile, and that is just one area of advantage.
As we have seen, people who drink coffee on a regular basis have a reduced risk of type 2 diabetes, some forms of cancer, heart disease and liver disease. Additionally, drinking coffee tends to improve mood and is even associated with longer life.
So, with all those health benefits – why wouldn’t you treat yourself to coffee every day?
Now, I've shown that coffee itself isn't harmful and can be beneficial for health. But for many of us, coffee is only part of our coffee habit. As you can probably imagine, the best way to get health benefits from coffee would be to drink it black. However, many people don't find this appealing.
Instead, we tend to include creamers (or half and half) and/or sugar to make the drink more palatable.
Both of those of approaches aren't particularly good for health. After all, sugar adds in no nutritional value and has damaging impacts on the body. Likewise, cream or half and half is an additional source of calories, which isn't good if you are trying to lose weight.
All of this wouldn't be so bad if you only had 1 cup of coffee per day but many people have more than that and don't take their calorie consumption into account.
If you want the most health benefits from coffee, paying close attention to what you put in it is critical.
There are a range of other options out there. For example, some people use artificial sweeteners, although there is considerable debate about whether these do more harm than good. Likewise, others might choose options that are more natural, such as honey. While that is a better choice for health, you still have to be aware of the calories.
Another alternative is butter. To me, that choice is extremely weird but it is growing in popularity. Now, it's true that butter isn't as unhealthy as people assume (actually, it's pretty healthy), nevertheless, it mightn't be a good choice for coffee.
One final set of options is to use milk instead of a creamer. This approach is actually common in a lot of countries outside of America and it can certainly be a good option. For one thing, you get less calories than you would with cream and coffee with milk is easier to drink than black coffee for many.
Everyone differs in their preferences for coffee, so the right approach for one person may be unappealing for another person. Nevertheless, if you want the most out of your coffee, being aware of what you put into it is absolutely critical.
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