Good News About Coffee
By Joyce Hendley
Coffee lovers may be raising their cups—and perhaps eyebrows—at the recent
news (in the Journal of Agricultural and Food Chemistry) that the drink
contains soluble fiber, the type that can help lower cholesterol. With about 1
gram per cup, coffee’s fiber impact is modest. But the report is the latest in
a growing stream of positive news about coffee.
Some of the most promising findings come from studies of diabetes. When
Harvard researchers combined data from nine studies involving more than 193,000
people, they found that regular coffee drinkers had a significantly lower risk
of type 2 diabetes than those who abstained. The more they drank, the lower
And, despite coffee’s reputation for being bad for the heart, recent
epidemiologic studies haven’t found a connection; some even suggest coffee can
be protective. A study in February’s American Journal of Clinical Nutrition
reported that healthy people 65 and over who drank four or more cups of
caffeinated beverages daily (primarily coffee) had a 53 percent lower risk of
heart disease than non-coffee-drinkers.
It’s even more beguiling when you consider that the immediate effects of
drinking coffee tend to go in the opposite direction, raising heart rate and
blood pressure and temporarily making cells more resistant to insulin. “But
those effects are probably short-lived, as people develop a tolerance,”
explains Frank Hu, M.D., Ph.D., associate professor of nutrition and
epidemiology at Harvard School of Public Health, who has studied coffee
extensively. “In the long term, beneficial components in coffee may have
stronger, more lasting effects.”
How coffee might work isn’t clear; the studies weren’t designed to identify
cause-and-effect relationships. Antioxidants, such as chlorogenic acid (related
to polyphenols in grapes), are likely players: coffee has more of them per
serving than blueberries do, making it the top source of antioxidants in our
diets. Antioxidants help quell inflammation, which might explain coffee’s
effect in inflammation-related diseases like diabetes and heart disease.
Magnesium in coffee might help make cells more sensitive to insulin. And
caffeine seems to have its own beneficial effects; the diabetes studies found
that those who drank regular coffee had lower risks of the disease than decaf
drinkers. Caffeinated-coffee drinking has also been linked with reduced risk of
Parkinson’s disease, gallstones, cirrhosis and liver cancer.
Bottom Line: For healthy adults, having two or three cups
of joe daily generally isn’t harmful and it may have health perks.
“I wouldn’t recommend drinking coffee to prevent disease,” says Hu.
Exceeding one’s caffeine tolerance—which varies—can cause irritability,
headache and insomnia. (Signs you might be over consuming: Yelling at
co-workers. Watching infomercials at 2 a.m.) The temporary rise in heart rate
and blood pressure could cause problems for people with heart disease, and new
moms should be aware that caffeine passes into breast milk. Hu has no plans to
change his own two-cup-a-day habit. “For most people who enjoy coffee, there’s
no reason to cut back.”