The International Coffee Organization reported that 1.4 billion cups of coffee are poured worldwide every day. With an astonishing number like that, it’s no wonder so many studies are being conducted to determine the health benefits of coffee. That’s a ton of coffee being drunk and 45 percent (or 400 million cups a day) of that number represents coffee drinkers in the United States alone.
A 2017 meta-analysis study published in the British Medical Journal sought to examine the health benefits of coffee consumption. Rather than conduct another study, they instead combed through an extensive collection of existing research and evidence to determine the health benefits of coffee consumption. After analyzing over 200 reports, the study concluded that coffee seems generally safe within usual levels of intake: three to four 8-ounce cups.
What are the active compounds in coffee?
The evidence tells us that coffee consumption is more likely to benefit health than harm it. But what is coffee really, and why is it so addicting for many? The active ingredients in coffee are mostly responsible for its addictiveness.
Coffee contains a complex mixture of active ingredients that has a positive effect on your body’s health. It comprises over 1,000 bioactive compounds, some with potentially therapeutic antioxidant, anti-inflammatory, antifibrotic, or anticancer effects. These properties merit a closer look at the benefits of coffee on the human body.
There are many factors that determine whether coffee is truly a benefit, including the degree of roasting, prep method, grind setting, and brew type. But the determinants don’t stop there; your individual genetics and gut microbiomes will determine how coffee metabolizes and ultimately impacts your health.
The key compounds in coffee include the following:
A stimulant and one of the most commonly consumed psychoactive substances in the world. Caffeine blocks an inhibitory neurotransmitter in your brain, which causes a stimulant effect. This effect leads to improved energy levels, mood, and other brain functions.
Chlorogenic acid is a natural antioxidant compound found in coffee beans. This compound works by inhibiting the enzyme alpha-glucosidase, which is responsible for breaking down carbohydrates. Studies have revealed that it may help with weight loss and decreased levels of blood pressure. Additional benefits may include lower blood sugar, improved mood, and protection against infections.
Cafestol and kahweol
Cafestol and kahweol are fat-soluble compounds known as diterpenes. Diterpenes are antimicrobial and anti-inflammatory compounds that are naturally present in the oil contained in coffee and in the grounds floating in the coffee. Paper filters trap cafestol and kahweol, leading to little, if any, change in cholesterol levels.
Further research also shows that diterpenes may also have some health benefits that are lost when they're filtered out. While still in the early stages of research, it is believed to have some anticancer effects and be good for the liver.
What are the health benefits of coffee?
There are conflicting conclusions about the health benefits of coffee. Some experts report that the chemical compounds in coffee can be beneficial to the human body. Several of the studies show that coffee drinkers have a lower risk of several diseases. Here are the pros:
1. Heart health
The health benefits of coffee include a lower risk of heart failure, stroke, and coronary heart disease. Coffee drinkers who consumed an average of three cups per day were less likely to die from cardiovascular disease (19 percent), coronary heart disease (16 percent) and stroke (30 percent). The 2017 meta-analysis found that the caffeine in the coffee may have at least a small benefit for cardiovascular health, including blood pressure.
2. Liver function
Drinking coffee in moderate amounts may reduce the damage caused by overindulging in your favorite alcoholic beverages. The 2017 study showed beneficial associations with liver functions, including a lower risk for non-alcoholic fatty liver disease (29 percent), liver fibrosis (27 percent), and liver cirrhosis (39 percent). Drinking one extra cup a day was also significantly linked with a lower risk of death from cirrhosis as well as a significantly lower risk of gallstone disease.
3. Lower risk of cancer
Coffee may reduce the risk of developing certain types of cancer: the chance of developing prostate, endometrial, melanoma, oral, leukemia, liver, and non-melanoma skin cancers may be lower in coffee drinkers. Studies reveal a correlation between high levels of coffee consumption and a decreased risk of liver cirrhosis and liver cancer, although further research is required before any definitive conclusions can be reached.
4. Lower risk of type 2 diabetes
There’s a connection between the number of cups consumed per day and the risk of developing type 2 diabetes. People who drank four to six cups of coffee and more than six or seven cups of coffee per day were at a lower risk of type 2 diabetes when compared to those individuals who drank less than two cups per day.
A separate study reported that increasing coffee consumption over a four-year period lowers your risk of type 2 diabetes while decreasing your consumption can increase your risk of type 2 diabetes in subsequent years. According to the research, people who decreased their coffee consumption by more than one cup per day increased their risk of developing type 2 diabetes by 17 percent.
5. Increased energy
The caffeine compound present in coffee is what gives you that extra jolt you need when you feel drained or tired. Caffeine is a stimulant that when absorbed into your bloodstream blocks the inhibitory neurotransmitter adenosine. As a stimulant, it enables your brain to produce more dopamine and adrenaline than usual.
This reaction leads to increased mood and energy levels. A number of controlled studies examined the effects of caffeine on the brain; the results show that caffeine can temporarily improve mood, reaction time, memory, vigilance, and general brain function.
6. Brain health
Caffeine is the reason why coffee can improve brain function and improve mood, reaction time, vigilance, and learning. The studies we reviewed show a consistent association with a lower risk of depression and cognitive disorders, especially Alzheimer’s disease and Parkinson’s disease.
As you age, your risk of dementia, Parkinson’s, and Alzheimer’s disease increases. Drinking coffee can improve brain function by stimulating the central nervous system, which promotes the release of other neurotransmitters like serotonin, dopamine, and noradrenaline. The evidence suggests that regular consumption (three to four cups) of black coffee reduces the risk of Alzheimer’s by 65 percent and Parkinson’s by 60 percent.
The benefits of antioxidants in coffee include a lower risk of cancer, heart disease, liver disease, diabetes, and premature death. Coffee contains Vitamin B2, B3, B5, manganese, potassium, and magnesium; combined with the antioxidants also present in coffee, these nutrients help fight inflammation, which may be an underlying cause of many chronic diseases and cancer. One study concluded coffee contained more extra antioxidants than several popular fruits and vegetables; however, another study found that antioxidants dissolved in the production process.
What are the side effects of coffee?
Researchers agree the drinking coffee seems safe within usual patterns of consumption, except during pregnancy and among women whose risk of fractures is high. In pregnancy, it may lead to consequences like low birth weight, pregnancy loss, and first and second-trimester preterm birth.
In women who are at risk for fracture, the evidence suggests an increased risk of fracture; but this risk decreased in men. This may suggest that biological sex plays a significant role in the connection between coffee consumption and the risk of fracture. Here are some other notable risks:
Coffee drinkers are at a higher risk of developing endometriosis
Unfiltered coffee can increase cholesterol levels
Coffee can lead to an increased risk of urinary tract cancer
Sugary add-ins like creamers contain ingredients that may cancel out the health benefits of coffee
The health benefits of coffee may go beyond providing you with just the right charge you need to get going in the morning. The potential health benefits include protection against type 2 diabetes, Parkinson’s disease, liver cancer, liver disease, and the promotion of a healthy heart. While the caffeine in coffee may provide some anti-cancer benefits, it is also highly addictive and can cause insomnia and high blood pressure.
The jury is still out on whether coffee is healthy and energizing or harmful and addictive. Further research will need to be done to account for factors like the method of brewing, processing, and human genetics.
If you love your cup of joe, feel free to enjoy it in moderation (two to three cups) to get the health benefits, but be mindful to avoid the negative outcomes resulting from too much caffeine.
Absorption and urinary excretion of the coffee diterpenes cafestol and kahweol in healthy ileostomy volunteers https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2796.1998.00386.x
Antioxidant and Antiradical Activity of Coffee https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4665516/
Changes in coffee intake and subsequent risk of type 2 diabetes https://link.springer.com/article/10.1007%2Fs00125-014-3235-7
Coffee consumption and nutritional information https://www.coffeeandhealth.org/topic-overview/compounds-in-coffee-2/
Coffee to reduce risk of type 2 diabetes?: a systematic review https://www.ncbi.nlm.nih.gov/pubmed/22497654
Dietary Guidelines for Americans 2015-2020 Eight Edition https://health.gov/dietaryguidelines/2015/resources/2015-2020_Dietary_Guidelines.pdf
Intakes of Antioxidants in Coffee, Wine, and Vegetables Are Correlated with Plasma Carotenoids in Humans https://academic.oup.com/jn/article/134/3/562/4688575
Natural diterpenes from coffee, cafestol and kahweol induce apoptosis through regulation of specificity protein 1 expression in human malignant pleural mesothelioma https://jbiomedsci.biomedcentral.com/articles/10.1186/1423-0127-19-60
The impact of caffeine on mood, cognitive function, performance and hydration: a review of benefits https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-3010.2007.00665.x
What is it about coffee? https://www.health.harvard.edu/staying-healthy/what-is-it-about-coffee