1. Cancer
Over 1,000 chemicals have been reported in roasted coffee,
and 19 are known rodent carcinogens. However, most substances cited as rodent
carcinogens occur naturally and should not be assumed to be carcinogenic in
humans at exposure levels typically experienced in day-to-day life
2. Gastrointestinal problems
Coffee can damage the lining of the gastrointestinal organs,
causing gastritis and ulcers. The consumption of coffee is therefore not
recommended for people with gastritis, colitis, and ulcers
3. Anxiety and sleep changes
Many coffee drinkers are familiar with "coffee
jitters", a nervous condition that occurs when one has had too much
caffeine. It can also cause anxiety and irritability, in some with excessive
coffee consumption, and some as a withdrawal symptom. Coffee can also cause insomnia
in some. In others it can cause narcolepsy.
4. Cholesterol
A 2007 study by the Baylor College of Medicine indicates
that the diterpene molecules cafestol and kahweol, found only in coffee beans,
putatively raise levels of low-density lipoprotein or LDL in humans. This
increase in LDL levels is an indicator that coffee raises cholesterol. The
Baylor study suggests a possible link between cafestol, kahweol and higher
levels of cholesterol in the body.
5. Blood pressure
Caffeine has previously been implicated in increasing the
risk of high blood pressure. However,
recent studies have not confirmed any association. In a 12-year study of
155,000 female nurses, large amounts of coffee did not induce a "risky
rise in blood pressure"
6. Effects on pregnancy
Caffeine molecules are small enough to penetrate the
placenta and slip into the baby's blood circulation. Unlike adults, organs and
systems in fetuses are not full-fledged, therefore not capable of fully
metabolizing caffeine and excreting it. The energy booster tends to linger in
the fetus's blood ten times longer than in adults. High levels of caffeine are
bound to accumulate in the baby's body with frequent maternal consumption of
caffeine. Just like what it does to adults, caffeine could also send the baby's
pulse and breathing rate racing and affect its sleep pattern for an extended
duration.
7. Iron deficiency anemia
Coffee consumption can lead to iron deficiency anemia in
mothers and infants. Coffee also interferes with the absorption of supplemental
iron.
8. Coronary artery disease
A 2004 study tried to discover why the beneficial and
detrimental effects of coffee conflict. The study concluded that consumption of
coffee is associated with significant elevations in biochemical markers of inflammation.
This is a detrimental effect of coffee on the cardiovascular system, which may
explain why coffee has so far only been shown to help the heart at levels of
four cups (24 fl oz or 600 ML) or fewer per day.