Grounds to Give Up Coffee? : Health: Research links the brew to cancer, stress and, most recently, heart attacks. But other studies show that it has positive effects on the mind and body.
In the New York offices of the National Coffee Assn., officials last week weighed the latest bombshell against their industry with the kind of calm resignation that results from frequent attacks.
Asked about a new study showing that heavy coffee consumption can boost the risk of heart attacks, George Boecklin, the association’s president, said he preferred to keep his silence until a panel of scientific experts reviews the study for the association. “We’d rather not go off half-cocked,” he said with a sigh.
Since the early ‘60s, the association--which represents Folgers, Maxwell House and other coffee makers--has weathered repeated studies reporting negative health effects of America’s beloved wake-up beverage.
“You get this sensationalism about coffee,” says Dr. Harvey Wolinsky, a New York cardiologist who says coffee is a safe product. “Someone is always saying, ‘Coffee is no good.’ ”
But, so far, no one can say, unequivocally, that coffee is bad for you, Wolinsky and other experts say. Moreover, along with the negative findings have been positive reports about coffee. Researchers so far this year have reported that:
* Elderly coffee drinkers are more sexually active than non-coffee drinkers.
* Drinking a cup of coffee in the morning really does makes you feel better and more alert.
* Coffee, particularly boiled coffee, increases blood cholesterol levels.
* Coffee may protect against cancer of the colon and rectum.
* Coffee may be related to cancer of the bladder.
* Coffee can magnify the effects of stress.
* Coffee can increase the risk of heart attack.
There is particular irony in the recent study on heart attack risk, says Wolinsky, of the Mount Sinai Hospital and Medical Center in New York.
The researchers, from Kaiser Permanente Medical Center in Oakland, found that people who drink four or more cups a day increase their risk of a heart attack by 40%. But in 1973, the same group performed a similar study and found no adverse risks associated with coffee.
“They re-examine the data and they find coffee is no good for you. And this is the same group that said coffee is good for you!” says Wolinsky, with a screech in his voice.
Dr. Arthur Klatsky, chief of cardiology for Kaiser Permanente Medical Center in Oakland, said, “Our new study is consistent with the view that heavier coffee use increases myocardial infarction risk. We now suggest that persons at high risk of myocardial infarction should limit coffee use to less than four cups a day.”
For all the interest in coffee and health--more than 500 scientific studies in the last 40 years--the drink consumed in moderation appears to be relatively benign. But, pour yourself a cup and judge for yourself.
(Incidentally, the “cup” referred to in most studies is five ounces; the mug consumed by most Americans is at least eight.)
Let’s start with the most, well, sexy stuff:
SEX
A study of 800 Michigan residents age 60 and older found that 62% of regular coffee drinkers still enjoyed an active sex life compared with 37% of the non-coffee drinkers. The study also found that older, male coffee drinkers were less likely to be impotent.
Researchers didn’t ask if the coffee drinkers consumed regular or decaf or how much coffee they drank. But, as one Chicago newspaper columnist noted: Goodby, Mrs. Olsen; hello, Tom Cruise.
ALERTNESS
There must be some reasons why 53% of all American adults drink at least one cup of coffee in the morning.
Research from the Naval Health Research Center in San Diego found that among two groups of young men, both of which received a verified good night’s sleep, those consuming a capsule of caffeine equivalent to the amount in two cups of coffee said they were in a better mood and more alert than those receiving a placebo.
Swiss researchers also found that coffee can increase work efficiency by improving the brain’s capacity to process information.
But results on coffee and brain power are mixed. Other studies have shown that while coffee consumption can speed performance of some mental tasks, it does not necessarily improve the quality or outcome of those tasks.
Coffee, of course, can also keep some people awake at night.
Caffeine apparently mimics a brain chemical called adenosine, which blocks the brain chemicals that cause alertness. But caffeine binds to adenosine receptors in the brain making adenosine ineffective and allowing the chemicals that cause alertness to remain active.
Coffee cannot erase the effects of alcohol. Studies show that a drunk driver topped off with three cups of coffee is no less dangerous.
NUTRITION
Coffee does not provide any vitamins or minerals, says Gail C. Frank, a spokeswoman for the America Dietetic Assn. and a professor of nutrition at Cal State Long Beach.
It does speed the excretion of calcium from the body. However, this deficit can be overcome by adding a couple of teaspoons of milk to the coffee.
A cup of black coffee has no calories; with a teaspoon of sugar and a tablespoon of heavy cream, one cup has about 150 calories.
ADDICTION
Coffee is not crack. But among heavy drinkers--five or more cups a day--it can lead to a kind of dependency.
Studies show that when heavy coffee drinkers quit cold turkey they experience nervousness, irritability and the inability to concentrate. Many also suffer a severe headache. But studies fail to show that deprived coffee drinkers are compulsive about obtaining their “fix” as, say, a heroin user.
CANCER
Studies have examined whether coffee increases the risk of cancer of the bladder, urinary tract, kidney and breast; most of the works have been inconclusive and some have found no link. One study tying caffeine to pancreatic cancer was later retracted.
Earlier this year, a panel of experts convened by the World Health Organization concluded that coffee may protect against cancer of the colon and rectum. A Boston University study found a 40% lower risk of colon and rectal cancer among people who consumed five or more cups a day. But the WHO panel also reported that coffee may increase the risk of bladder cancer.
Some studies suggest an association between caffeine and a benign breast ailment, fibrocystic disease, which can lead to breast cancer.
While other studies have dismissed the connection between caffeine and breast cancer, Frank says dietitians often advise women at high risk for breast cancer to avoid excessive doses of caffeine--such as 10 servings a day--from sources such as coffee, colas and chocolate.
“Caffeine is a concern for some women,” Frank says. “We think there is a threshold of safety.”
ULCERS
Coffee apparently isn’t a major cause of stomach disorders. It can cause heartburn and seems to aggravate ulcers. But researchers say it doesn’t cause ulcers.
Coffee is something of a laxative and in some sensitive individuals can cause diarrhea, Frank says.
“Coffee, in some people, interacts with the gastrointestinal tract and gives them an upset, such as diarrhea,” she says.
BIRTH DEFECTS
It is hardly surprising that when scientists fed laboratory animals massive doses of caffeine, their offspring were born with serious defects. A recent study reported that huge doses of just about any substance cause disease in lab animals and that those results are not indicative of the effects moderate amounts of the same substance might have in humans. It remains unproven whether coffee consumed by pregnant women causes birth defects or low birth weight babies.
Nevertheless, doctors advise pregnant women to avoid caffeine because it does cross the placenta to the fetus.
Women trying to become pregnant might also want to limit their coffee intake. A Yale study found that women who consumed several cups of coffee a day nearly doubled their risk of miscarriage.
STRESS
Coffee drinkers who exercise and have high blood pressure or are at risk for it have reason to be concerned by a new study from the University of Oklahoma.
Researchers there found that coffee combined with the cardiovascular stress of exercise can elevate blood pressure, especially among people already at high risk.
The scientists suspect that caffeine increases the body’s production of the natural brain stimulant epinephrine, which makes the heart beat faster.
Researchers at McGill University in Montreal checked the blood pressures of salespeople paid on commission as they sold their wares and found that caffeine combined with job stress produced higher blood pressure readings than just job stress alone.
CHOLESTEROL
The way you prepare coffee may have something to do with whether it raises your cholesterol. The method that most Americans use--employing electric drip machines or stove-top filter pots--appears safe.
In a study from the Netherlands reported last November, people who drank boiled coffee, common in some parts of Europe, experienced a 10% increase in total cholesterol levels. Those who drank filtered coffee experienced no changes in cholesterol levels.
Researchers don’t know why boiled coffee causes such an increase. Boiled coffee requires hotter water that must stay in contact with the grounds longer, perhaps increasing the levels of an unknown lipid that boosts cholesterol. Or perhaps filters screen out some adverse element in coffee.
Another recent study found decaffeinated coffee increases cholesterol levels. This was particularly upsetting to coffee drinkers who switched to decaf in hopes of reducing any harmful effects of caffeine.
Stanford researchers found that decaf drinkers experienced a slight increase in low-density lipoprotein (“bad”) cholesterol. Instead of blaming caffeine, however, the Stanford scientists suggest that, because regular and decaf are made from different types of beans, a substance in decaffeinated beans causes the higher cholesterol level.
The increase in cholesterol in the decaf drinkers was not significant enough to warrant a change in habits, said researcher Sheldon Margen, a professor of public health nutrition, in a recent issue of the University of California, Berkeley, Wellness Letter.
HEART ATTACK
The new study by Kaiser researchers once again raises doubts about the safety of excessive coffee consumption, especially among people at high risk for heart disease.
But, in general, experts largely agree that moderate coffee consumption--less than four cups a day--is safe.
According to a long-running study on heart disease and lifestyle risk factors called the Framingham Heart Study, coffee intake does not influence cardiovascular disease.
