We believe that coffee is more than just a drink: It’s a culture, an economy, an art, a science — and a passion. Whether you’re new to the brew or an espresso expert, there’s always more to learn about this beloved beverage.
People most commonly drink coffee to relieve mental and physical fatigue and to increase mental alertness. Coffee is also used to prevent Parkinson disease, Alzheimer disease, dementia, and cognitive decline. It is also used to prevent gallstones, gout, type 2 diabetes, and certain types of cancer.
Rectally, coffee is used as an enema to treat cancer. Coffee enemas are used as a part of the “Gerson Therapy.” In the Gerson Therapy, cancer patients are treated with caffeinated coffee in the form of enemas every four hours on a daily basis. During the treatment, people are given a diet of liver, vegetables, and a variety of other supplements.
In excess, coffee, and more particularly, caffeine, can cause problems. But fretting about two or three cups a day, or even more, is fading as study results suggest health benefits from coffee keep on coming in. In 2011, researchers reported findings that coffee drinking is associated with a lower risk of depression among women, a lower risk of lethal prostate cancer among men, and a lower risk of stroke among men and women.
Caffeine has been studied more than any other ingredient in coffee, and it tends to get credit if the body part benefited is the brain. But coffee contains literally a thousand different substances, and some of the lesser lights are thought to be responsible for healthful effects in other parts of the body. Some studies show caffeinated and decaffeinated coffee as having the same effect, which suggests that something else in coffee is involved.
It gets complicated, though. Caffeine and some of these other substances in coffee seem to have their good and bad sides, and coffee’s overall effect may depend on how much they cancel each other out.
Caffeine is the most commonly consumed psychoactive drug in the world, and some of its behavioural effects (such as arousal) may resemble those produced by cocaine, amphetamines, and other stimulants. Coffee consumption accounts for about 75% of the adult intake of caffeine in the United States, although that might be changing among younger adults with the growing popularity of energy drinks.
The caffeine content of coffee varies greatly, depending on the beans, how they’re roasted, and other factors, but the average for an 8-ounce cup is about 100 milligrams (mg). Tea has about half as much caffeine as coffee. Decaffeinated coffee has some caffeine, but the 2 to 4 mg in an 8-ounce cup is a smidgen compared with the caffeinated version. The lethal dose of caffeine is about 10 grams, which is equivalent to the amount of caffeine in 100 cups of coffee.
Caffeine gets absorbed in the stomach and small intestine and then distributed throughout the body, including the brain. The amount circulating in the blood peaks 30 to 45 minutes after it’s ingested and only small amounts are around eight to 10 hours later. In between, the amount circulating declines as caffeine gets metabolized in the liver.
Considerable controversy exists on the association between coffee consumption and cardiovascular disease (CVD) risk. A meta-analysis was performed to assess the dose-response relationship of long-term coffee consumption with CVD risk.
Coffee is one of the most widely consumed beverages around the world; thus, investigating whether coffee consumption is associated with chronic disease risk has important public health implications. The relationship between coffee consumption and risk of coronary heart disease was first studied in the 1960s, given that the prevalence of both coffee drinking and coronary heart disease (CHD) were high in Western countries. Short-term metabolic studies found that caffeine ingestion acutely induces cardiac arrhythmias and increases plasma renin activity, catecholamine concentrations, and blood pressure.
In the 1980s, cross-sectional studies found a positive association between coffee consumption and serum total cholesterol concentrations, which might be related to the coffee brewing method (i.e. boiled or unfiltered coffee). A later randomized trial showed that boiled coffee consumption increased serum cholesterol. From the 1980s to the 2000s, many case-control studies, which are prone to recall and selection bias, showed a positive association between coffee consumption and CHD risk.
Since 2000, the associations between coffee consumption and other cardiovascular diseases (CVD) outcomes such as stroke, heart failure, and total CVD mortality have also been more frequently studied. Meta-analyses have been published to summarize the association between coffee and risk of CHD, stroke, and heart failure. These meta-analyses did not support an association between coffee consumption and a higher CVD risk, but the shape of the association remains uncertain. Moreover, a number of additional studies have been published since the publication of these meta-analyses, and a recent meta-analysis showed that heavy coffee consumption was not associated with risk of CVD mortality.
Many studies have been done to see if there’s a direct link between caffeine, coffee drinking and coronary heart disease. The results are conflicting. This may be due to the way the studies were done and confounding dietary factors. However, moderate coffee drinking (1–2 cups per day) doesn’t seem to be harmful.
Caffeine-habituated individuals can experience “caffeine withdrawal” 12–24 hours after the last dose of caffeine. It resolves within 24–48 hours. The most prominent symptom is a headache. They can also feel anxiety, fatigue, drowsiness and depression.
Studies on coffee consumption variously claim that coffee harms the arteries, that it protects the heart, or that it has no effect on cardiovascular health. While some studies warn that drinking coffee can increase a person’s risk of cardiovascular events, others suggest that it can help maintain heart health and blood vessel function.
Some research has suggested that regularly drinking a lot of coffee contributes to aortic stiffness — this is when the aorta, which is the largest blood vessel in the human body, becomes less and less flexible. Aortic stiffness can contribute to the risk of cardiovascular disease.
At the same time, other evidence has indicated that drinking more than three cups of coffee a day can protect against atherosclerosis, a condition in which plaque builds up inside the arteries, preventing blood from flowing normally.
Now, a new study conducted by researchers from the Queen Mary University of London in the United Kingdom has found that even people who drink a significant amount of coffee each day do not experience arterial stiffness, meaning that coffee does not increase their risk of cardiovascular problems in this way.
These findings remained in place after the investigators adjusted for possible factors contributing to arterial stiffness, including age, biological sex, ethnicity, smoking status, alcohol consumption, height, weight, eating habits, hypertension (high blood pressure), high cholesterol, and diabetes.
In general, the widespread concerns many people have about the potentially deleterious effects of coffee on the heart have not been supported by recent scientific studies. It appears that, in the large majority of people, moderate coffee drinking is not detrimental to cardiac health, and in some cases may even be beneficial.