Remember the days when doctors used to advise their patients not to drink coffee as this could harm their hearts, give them ulcers, and make them overly nervous? Well, it’s still true today that in excess, coffee, and particularly caffeine, can cause health problems. But the fretting about two or three cups a day, or even more, is fading as study results suggestive of health benefits from coffee keep pouring in.
In the last few years alone, research continues to serve up health perks for coffee drinkers. Here’s a roundup of results of recent studies on coffee:
• Heart failure. Women who drink coffee are slightly less likely to develop heart failure than women who don’t drink coffee. Coffee drinking has little effect on heart failure in men.
• Stroke. Women who drink coffee are about 25 percent less likely to have a stroke than those who don’t. (The study didn’t include men.)
• Blood clot in the legs or lungs. Men and women who drink coffee may be less likely to develop a blood clot in the legs (deep vein thrombosis) or the lungs (pulmonary embolism) than non-drinkers.
• Premature death. In a 24-year study of female nurses, coffee drinkers — including those who downed four or more cups a day — were no more likely to have died than women who didn’t drink coffee.
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• Heart rhythm problems. Doctors often advise their patients with heart palpitations or other rhythm problems to stop drinking coffee and other caffeinated beverages. Northwestern University researchers reviewed the evidence for this recommendation. Of 11 studies in humans, one showed a link between caffeine and premature contractions of the ventricles, two showed problems associated with drinking a lot of coffee (more than nine cups a day), and the remaining eight showed no effect from drinking caffeinated beverages or avoiding caffeine. Although the researchers acknowledge that some people are more susceptible to the effects of caffeine than others, they suggest that caffeine in moderation may be fine for many people with a known or suspected heart rhythm problem.
• Beyond the heart. Drinking a few cups of coffee a day was linked to lower rates of estrogen-negative breast cancer, type 2 diabetes, and aggressive prostate cancer.
Caffeine is the most commonly consumed psychoactive substance in the world, and some of its behavioral effects (such as arousal) may resemble those produced by cocaine, amphetamines, and other stimulants.
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 may be responsible for some healthful effects in other parts of the body. Some studies show caffeinated and decaffeinated coffee as having essentially 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 effects may depend on how much they cancel out each other. The caffeine content of coffee varies greatly, depending on the beans, how they are roasted, and other factors, but the average for an eight-ounce cup of brewed coffee contains between 90 and 200 milligrams (mg) of caffeine, while an eight-ounce cup of black tea has 15 to 60 gm of caffeine. The average 12-ounce caffeinated soda has between 20 and 40 mg of caffeine. The lethal dose of caffeine is about 10 grams, which is equivalent to the amount of caffeine in 100 cups of coffee.
Coffee: A disease- by-disease report
Here is a brief summary of the effects of coffee on the various diseases and medical conditions:
• Alzheimer’s disease. Human and animal studies show hints of protection. Some preliminary evidence suggests activity against beta-amyloid plaque that may have a causative role in Alzheimer’s.
• Cancer. Studies suggest a lower risk for some cancers (endometrial, aggressive prostate, estrogen-negative breast, basal cell carcinoma — a type of skin cancer), but not others (esophageal). Antioxidant and anti-inflammatory substances could be responsible for possible anticancer activity.
• Diabetes. Effects on insulin and blood sugar levels that would promote diabetes seem to have a greater effect. Protection may come from increases in the hormone adiponectin and other factors that affect insulin and blood sugar levels.
• Depression. The study, which included 50,000 women with an average age of 63, found that women who drink four eight-ounce cups of caffeinated coffee daily are 20-percent less likely to become depressed than women who rarely drink coffee. The researchers suggested that one possible explanation for caffeine’s role in lowering depression risk is that caffeine appears to protect the brain against certain neurotoxins that interfere with the release of chemicals related to mood.
• Heart attack. Coffee drinking increases some factors (homocysteine) associated with higher risk. But moderate consumption (one to three cups a day) has been linked to a small decrease in risk. The evidence for a possible protective effect is stronger for women.
• Liver disease. Coffee drinking is associated with lower levels of enzymes that indicate liver damage and inflammation. Coffee may improve response to some treatments for hepatitis C. Findings suggest some protection against liver cancer. Cafestol and kahweol, substances found in unfiltered coffee, may be responsible for liver benefits.
• Parkinson’s disease. Studies show a moderate (25-percent) decrease in risk for coffee drinkers. The effect is less in women. Research has found evidence of activity in the part of the brain affected by Parkinson’s.
• Stroke. Moderate consumption (three to four cups a day) is associated with a lower risk. But chance of a stroke may increase immediately after intake, particularly among infrequent consumers. Researchers who published their stroke study in the September 2011 issue of the American Journal of Epidemiology could not pinpoint exactly how coffee protects a brain against stroke. However, they noted that the brain-protective qualities of coffee peaked at three to four cups per day. Having six cups, for example, did not provide additional decrease in the risk of stroke.
Risk and warnings
Despite coffee’s apparent health benefits, a coffee habit has some drawbacks, too. One can become dependent on caffeine for energy, though decaf drinkers do not face that problem. Similarly, caffeinated coffee can interfere with sleep. Even if you are able to fall asleep after consuming coffee in the late afternoon or evening, avoid doing so, as caffeine can prevent you from getting a restful sleep.
Caffeinated beverages can also exacerbate acid reflux symptoms. And individuals who are used to caffeine every day can suffer headaches and anxiousness when they go without their usual cup of Joe. Caffeine, of course, can also act as a diuretic, so you may experience a greater urgency to urinate after drinking a caffeinated beverage.
How much coffee one can drink each day depends on the individual. Some may notice negative effects with less, while others are able to have more with no negative effects. Most people can have two to three cups of coffee a day without negative side effects.
And, if you indulge in gourmet coffee drinks that contain high amounts of whipped cream, caramel, chocolate or other sweeteners, you run the risk of adding a significant number of calories and fat grams to your daily total and putting on weight as a result.
A health drink? Not quite
It is one thing to say that coffee may be good for you; it’s another to say it’s so good for you that drinking it should be recommended. No, we’re not there yet.
All of the favorable studies on the healthful benefits of drinking coffee are, indeed, good news for coffee drinkers. They can relax and enjoy their habit. And people who don’t drink coffee can find plenty of other things to do to help keep themselves healthy.