Caffeine 75loss of bone density in older women; studies controlling other factors (such
as cigarettes and drugs promoting calcium loss) found that caffeine had no
tendency to reduce bone density, but one study published in 2000 and tracking
almost 35,000 postmenopausal women found a slight correlation of caffeine
usage to broken bones—a correlation implying loss of density. Coffee drinking
is associated with loss of density. In contrast, examination of over 1,200 older
women in England showed that tea drinkers were less likely to have osteo-
porosis, leading investigators to wonder if something in tea, other than caf-
feine, affects bone density.
Investigators examining caffeine consumption in a group of 8,000 men who
were tracked for three decades discovered that the more caffeine someone
ingested over the years, the less likely the person was to come down with
Parkinson’s disease. In a group of 46,000 men tracked for a decade, increased
consumption of caffeinated coffee was linked to decreased likelihood of
having gallstones; consumption of decaffeinated coffee did not have such a
link. As one analyst pointed out, such associations are interesting but do not
prove cause and effect; for example, perhaps some physical aspect leading to
Parkinson’s disease also makes caffeine beverages unappealing—thus persons
without the disease would consume more caffeine beverages than sufferers
do, but that consumption would not mean that caffeine prevents the affliction.
Mice experiments demonstrate that if caffeine is administered in the right
amount and at the right time before exposure to radiation, the drug will allow
mice to survive otherwise lethal amounts of radiation.
Drawbacks.In the 1990s, 20% of the U.S. population was believed to be
using over 700 mg of caffeine each day. That is enough to produce behavior
mimicking an anxiety neurosis. If a person only ingests caffeine through phar-
maceutical preparations or food products with labels listing caffeine amounts,
intake can easily be measured. The amount in a restaurant cup of coffee is
more difficult to measure; one rule of thumb says 100 mg to 150 mg.
The substance can accelerate pulse rate; it can also make people more pee-
vish and jumpy (even promote panic attacks) and interfere with getting good
sleep. Caffeine can cause heartburn and increase urine output. Experimenta-
tion has confirmed that the drug’s tendency to promote loss of body fluid will
dry the vocal cords and affect voice quality.
Analysis of over 30 years of reports about caffeine and blood pressure found
that the drug reliably increased blood pressure when persons began using it
but that the effect did not persist in all users. Investigators measuring blood
pressure among medical students found caffeine raising the readings far
enough that anyone at risk for high blood pressure should avoid the drug
during times of stress. Persons with coronary artery disease may be at signif-
icant risk for sudden cardiac arrest if they drink more than 10 cups of coffee
a day.
Excessive doses can dangerously reduce blood potassium levels, damage
muscles, produce extremely rapid heartbeat, and cause delirium and seizures.
As the twenty-first century began a case report associated caffeine with retina
damage in several persons.
Abuse factors.Coffee was formerly treated as an illicit drug. Centuries ago
possession was a death penalty offense in Spain and the Near East. In the