QUESTION: I gave up coffee years ago because it made me too
jittery, but my husband still drinks coffee -- sometimes four
or more cups -- every day. I've always been under the
impression that too much caffeine is bad for your health. Is
there harm in drinking so much coffee? Are there any health
benefits from drinking it?

ANSWER: In excess, coffee, and more particularly,
caffeine, can cause problems for some people: Nervousness,
rapid heart action, heartburn and excessive urination head the
list. But study results keep coming that suggest coffee does
have some health benefits.

Recently, researchers reported that coffee drinking is
associated with lower risks of depression, lethal prostate
cancer and stroke. There are also reports of possible
protective effects against illnesses ranging from Parkinson's
disease to diabetes to some types of cancer.

Caffeine has been studied more than any other ingredient in
coffee. But coffee contains literally a thousand different
substances. And some of these lesser-known substances may be
responsible for healthful effects in various parts of the body.

In fact, some studies show that caffeinated and decaffeinated
coffee have similar effects, which suggests that something
besides caffeine is involved.

It gets complicated, though. Caffeine and some of the other
substances in coffee seem to have their good and bad sides.
Coffee's overall effect may depend on how much the positive and
negative effects balance out.

Here's a rundown of how coffee is thought to affect various
medical conditions:

• Alzheimer's disease: Some evidence suggests protection
against beta-amyloid plaque that may have a role in causing
Alzheimer's.

• Cancer: Studies suggest a lower risk for some tumors
(endometrial, aggressive prostate and estrogen-negative breast
cancers). Antioxidant and anti-inflammatory substances could be
responsible.

• Diabetes: Regular caffeine use is associated with lower risk,
and high intake (three to six cups a day) seems to have a
greater effect. Protection may come from factors that affect
insulin and blood sugar levels.

• Heart attack: Coffee drinking increases some factors
(homocysteine) associated with higher risk. But one to three
cups a day has been linked to a small decrease in risk.

• Liver disease: Coffee drinking is associated with lower
levels of enzymes that indicate liver damage and inflammation.

• Parkinson's disease: Studies show a 25% decrease in risk for
coffee drinkers. The effect is smaller in women.

• Stroke: Three to four cups a day is associated with lower
risk. But chance of a stroke may increase immediately after
intake, particularly among infrequent drinkers.

• Migraine headache: The caffeine in coffee helps ease migraine
headache in some people by narrowing the expanded blood vessels
in the brain that cause migraine pain.

Caffeine can also be a performance enhancer, strengthening
muscle contraction and offsetting effects of physical exertion.
But, especially in the short term, it also has negative
effects, which include raising blood pressure and increasing
levels of homocysteine, insulin and possibly cholesterol.

Coffee drinkers concerned about cholesterol weren't happy about
some early study results showing that coffee seemed to increase
cholesterol levels. But the bad news turns out to be not so
bad, because the cholesterol-raising effect seems to be limited
to unfiltered coffee.

Follow this link:
Harvard Medical School Adviser: If you enjoy coffee, go ahead and drink it