We are a culture that simply can’t get enough of coffee. 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 (1).
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 (2).
So, it’s clear that some of us see benefits of coffee drinking.
Despite that popularity, 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 many 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 be good for you – rather than causing harm. For that matter, this is a topic that I have covered extensively in other posts and there are some clear advantages to drinking coffee regularly.
So, how do the positives of drinking coffee stack up? What about the negatives? Is coffee actually healthy or does it ultimately do much more harm than good? In this post, we’re looking at the health benefits that coffee offers – ones that have been scientifically proven.
1. Promotes Weight Loss
Coffee is well-known as a tool for weight loss – and does so in multiple ways. The first is simply that coffee can decrease appetite for many people (3). This isn’t an area that has been studied extensively and probably isn’t true for everyone.
But, many people do find that coffee lowers appetite. And, as Precision Nutrition reports, this effect also occurs in non-caffeinated coffee, so it may be related to other compounds in coffee.
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 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 as well
2. Coffee Lowers Type 2 Diabetes Risk
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:
Data from Ding et al., 2014
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
3. Promotes Significant Mood Improvements
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 reduces 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
4. May Protect Against 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.
Some of these studies have even indicated that moderate consumption of coffee can lower the risk of heart disease (16,17). This includes a 2017 study in Korean women (18). One mechanism may be the way that long-term coffee consumption can decrease hypertension risk (19).
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 (20).
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 (21). Likewise, a meta-analysis indicated that coffee may reduce the risk of liver cirrhosis (22).
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
5. Has The Potential to Lower Cancer Risk
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) (23) and research has failed to find a causal link between coffee and cancer (24,25).
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 (26). 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 (27).
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 this potential to decrease coffee 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 (28). Coffee may also lower the risk of oral and pharyngeal cancers (29,30).
Finally, a meta-analysis found that drinking more than 5 cups of coffee per day was associated with a reduced risk of colorectal cancer (31).
Coffee consumption has been linked to decreases in the risk of prostate, endometrial, colorectal and liver cancer
6. Can Improve Brain Function
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 (32).
What’s more, caffeine is sometimes promoted as a nootropic to improve mental function.
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) (33).
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 (34).
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.
Data from Ross et al., 2000
This particular study considered outcomes from a 30 year follow-up and included 8,004 participants (35). 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 (36). 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 (37). 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
7. Can Help You Live Longer
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 (38). 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.
Data from Freedman et al., 2012
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 (39).
Data from Ding et al., 2015
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 (42).
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 (43).
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 (44,45).
This field is still a fairly new one but one piece of recent research did find that coffee consumption was associated with longer telomeres in nurses (46), 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 (47) as well as gallstones (48,49). 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 (50).
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.
There is also an indication that caffeine may help to improve sports performance, in moderate doses. The site Ironman provides more details about this association. While many athletes would rely on caffeine supplements to get this benefit, coffee itself would also be a way to increase performance.
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 (51).
Other health benefits that have been linked to coffee consumption include protection against kidney stones, gallstones, tinnitus and breaks in DNA
How Safe and Beneficial is Coffee Really?
It’s clear that drinking coffee comes with some powerful health benefits. And, in many ways, this isn’t surprising at all. Coffee beans are packed with plant-based compounds, many of which have direct impacts on our body.
This area is one that Chemistry World turns to in considerable detail. Their article on the topic is a great place to turn if you want to understand more about why coffee impacts health so dramatically.
Still, as with any food or drink, coffee isn’t an amazing cure-all and it won’t suit everyone. Anyone who is sensitive to caffeine may want to rely on decaf instead or avoid coffee altogether (tea makes a good alternative). The same is true for people with heart conditions and for pregnant women.
Additionally, excessive coffee consumption does come with some risks, largely because of the caffeine content.
The balance of research suggests that you will get the most benefits from 2-4 cups of coffee per day. While some studies have found advantages at higher levels (including contributions to longevity), risks generally increase with consumption as well.
So, if you can control your consumption, there is no reason why you can’t regularly drink coffee every day. 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.
Likewise, you can turn to approaches like cold brew coffee if you want something different. Some people even use protein powder in their coffee, as a way to get the benefits of protein and coffee at the same time.
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