Although the art of wine making
is some 7,000 years old, the process of fermentation was not understood
until the discoveries of Louis Pasteur in the 19th century. Wine is
palatable and resistant to deterioration only after it has undergone
fermentation, which is a type of controlled spoilage. Alcohol, a waste
product of fermentation, is toxic to all living beings; even the yeasts that
excrete it cannot tolerate an environment of more than 15 percent alcohol,
which is why fermentation stops at about this concentration. Most French
wines are about 12 percent alcohol, and North American wines, 13 to 14
percent. Extra alcohol is added to fortified wines, such as sherry and port.
THE COMPONENTS OF WINE
Red wine is made from purple
grapes, but white wine is not necessarily made from white grapes. Many white
wines are made from purple grapes, but the skins are removed before they
color the fermenting juice, called must. The skins contain most of the
bioflavonoids, phenols, tannins, and other compounds that give wine its
flavor and healthful properties. The longer the must stays in contact with
the skins, the deeper the color will be. Some dessert wines are made with
specially overripened grapes to achieve a prized sweetness and a rich
Four ounces (120 ml) of red wine
contain about 80 to 90 calories, compared to 75 to 85 in the same amount of
white wine and 175 in dessert wine. Many wines have trivial amounts of
minerals; red wine has a trace of iron.
WINE AND THE HEART
Numerous studies show that
moderate consumption of alcohol -- one to two 4 oz (120 ml) glasses of wine
a day, preferably with a meal -- is associated with a lower risk of heart
disease. According to a 1991 report, the French had a heart attack rate only
one-third as high as that of North Americans, despite consuming as much or
more fat as North Americans. Wine consumption may be at least partly
responsible for this phenomenon, known as the "French paradox." Annual wine
consumption in North America is between 2 to 3 gal (8-11 liters) per person,
compared to about 15 gal (57 liters) per person in France.
Researchers have not determined
what it is in wine that may prevent heart attacks, but some theorize that
compounds such as quercetin and resveratrol in grape skins, as well as other
bioflavonoids, may be responsible. These compounds tend to make the blood
less sticky and less likely to form clots. It is thought that the French
habit o drinking wine with meals may provide the small but regular intake of
alcohol needed to reduce clot formation, a cause of most heart attacks. the
bioflavonoids also have antioxidant properties and may help prevent damage
to the artery wall and help keep the arteries dilated. Still other research
suggests that moderate amounts of wine may raise the levels of the
protective HDL (high density lipoprotein) cholesterol.
OTHER HEALTH BENEFITS
Studies are under way looking at
other benefits from the resveratrol found in wine. it is believed that it
has a preventative effect on several types of cancer, including colon and
prostate cancer. Laboratory studies indicate that the anthocyanin pigments
and tannins in wine can fight viruses, but this effect ahs not been proved
in humans. Tannins can inhibit the growth of plaque-forming bacteria on the
teeth and may protect against cavity formation. Other studies are exploring
the link between wine consumption and lowered risk of dementia.
Wine appears to contain
substances ( still to be identified ) that slow the rate of alcohol
absorption; studies show that a moderate amount of wine has a less
intoxicating effect than the same volume of distilled liquor. still, some
claim that wine makes them more sleepy than other alcoholic beverages do;
this effect may be due to ingredients other than alcohol.
The benefits of moderate wine
drinking, which may extend to reducing the risk of some cancers, are lost
when consumption exceeds 8 oz (240 ml) a day. Overconsumption can increase
the risk of obesity, stroke, breast cancer, high blood pressure, as well as
alcoholism, and cirrhosis and other liver disorders. even moderate alcohol
consumption may raise the risk of hemorrhagic stroke (involving a burst
blood vessel). In addition, heavy use of alcohol in early pregnancy can
cause birth defects.
Most wines contain sulfites and
preservatives that can trigger allergic reactions in susceptible people.
Wine, especially red, is a common trigger of migraines.