the years coffee has been blamed for causing everything from
high blood pressure and high cholesterol (and thus heart disease)
to pancreatic cancer, fibrocystic breast disease, and bone
loss. The main focus has been on caffeine, one of the most
extensively studied substances in food. But in nearly every
instance early research linking coffee or caffeine to health
problems has been refuted by better subsequent studies. "Not
guilty" has repeatedly been the verdict. The pendulum
has swung so far that some researchers now suggest that coffee
may actually have health benefits.
usually contains anywhere from 60 to 120 milligrams of caffeine
in six ounces. Caffeine's benefits are well known. It is a
mild psychoactive substance--it stimulates the central
nervous system. Thus, it improves reaction time, mental acuity,
alertness, and mood, wards off drowsiness, and helps millions
wake up and feel better in the morning. It also has an analgesic
effect, which is why it is added to some pain relievers.
all plant foods, coffee (derived from a bean) contains many
naturally occurring chemicals--more than 1,000 have been
identified so far--some potentially harmful, some potentially
healthful. As in tea, many of the beneficial substances are
antioxidants, which help protect against cell-damaging free
radicals, and thus may reduce the risk of heart disease and
cancer. In fact, a recent study found that coffee is the No.1
source of antioxidants in the U.S., largely because Americans
drink so much of it.
that's not enough, a handful of recent studies have
linked coffee or caffeine to a reduced risk of several diseases:
Type 2 diabetes. In February
researchers looking at 88,000 women in the Nurses'
Health Study at Harvard found that those who drank at least
two cups of coffee a day--regular or decaf--have
a lower risk of diabetes. Several previous studies of men
and women have had similar findings, though in men it may
take at least four cups a day to have this effect.
Parkinson's disease. In a well-designed study
from Honolulu, men who drank no coffee were two to three
times more likely to develop the disease than those who
drank one to four cups a day. Decaf was not included in
Symptomatic gallstone disease. In 2002 another part
of the Nurses' Health Study suggested there's
a protective effect, but it seemed to take four cups a day.
Caffeine is thought to be the primary protective ingredient.
Three years earlier the same researchers found a reduced
risk in men.
Liver damage. Regular coffee and tea may help prevent
liver disease in people at high risk (due to alcoholism,
obesity, or diabetes, for instance), according to a recent
study in Gastroenterology.
easy to see why some people would worry about coffee. First
of all, because caffeine is a stimulant, it can cause jitters
and insomnia. It can also boost heart rate, which is why people
with certain heart problems are sometimes advised to avoid
it. Coffee can also cause stomach upset and heartburn.
the effects of coffee can be confusing to evaluate. Here are
Caffeine can indeed raise blood pressure and heart rate
briefly in those not used to it, though this effect varies
greatly from person to person. The key question is whether
habitual coffee drinking leads to hypertension. And
the answer is no, according to most research, including
a recent study of 155,000 women.
A few studies have found that large quantities of unfiltered,
European-style coffee (regular or decaf) can boost blood
cholesterol slightly. However, paper filters seem to trap
whatever culprits may be in the grounds. Most research has
found no increase in cholesterol or cardiovascular risk
from coffee drinking in general.
While caffeine was a suspected risk factor for weak bones,
that may be because people who drink lots of coffee tend
not to consume milk, thus missing out on calcium and vitamin
Overall, people who drink lots of coffee are more likely
to smoke, eat poorly, and drink too much alcohol. Researchers
take such factors into consideration, but they can't
adjust for all of them.
for pregnant women: Some studies have indicated that
high doses of caffeine may raise the risk of miscarriage and
birth defects and possibly reduce fertility. Even though the
evidence for this is not clear-cut, to be safe, pregnant women
should drink no more than two cups a day.
to the wise: There's no health reason to deprive yourself
of coffee if you like the lift it gives and the sociability
it affords, unless you suffer adverse effects. On the other
hand, though it won't be surprising if coffee producers and
servers soon start promoting coffee as a health drink, the
potential benefits are still too uncertain to lead anyone
to start drinking coffee. Drink it only if you enjoy it.