I am a longtime former immigrant from the US, but I never got around to liking
coffee – except occasional treats of coffee ice cream or cake. I prefer drinking
tea, like the British. But I have heard recently that there are health benefits
from drinking coffee regularly. What benefits are there, what is the mechanism
and have these claims been proven scientifically? If so, should I start drinking
coffee even though the taste doesn’t really appeal to me? – R.S., Netanya
Judy
Siegel-Itzkovich replies:
A recent issue of the Hebrew-language Israeli Journal
of Family Practice relates at length to this issue. Dr. Sharon Maor, a clinical
and sports dietitian at the Wingate Institute for Physical Education near
Netanya and at Clalit Health Services, notes that coffee is an amalgamation of
some 1,000 components, including carbohydrates, fats, vitamins (vitamin B3 and
vitamin E), minerals (magnesium and potassium), alkaloids such as caffeine,
organic compounds and nutritional fibers. It is one of the foods richest in
antioxidants, which fight oxygenfree radicals that cause aging and the decline
of cells in the body.
Many scientific studies, Maor writes, have
investigated the connection between drinking coffee and health, and there is
increasing evidence of a positive connection between various types of coffee and
the prevention or lowered risk for diseases. But there are methodological
problems in coffee research, such as the varying amount of caffeine according to
the type of coffee, the way coffee is prepared, the size of the cup or glass
reported in studies, how long the coffee beans have been roasted and various
processes that influence the amount of nutrients in coffee. Nevertheless,
research does testify to health benefits.
Long-term controlled studies
have shown that caffeine disrupts glucose tolerance and reduces sensitivity to
insulin during the period of the experiments. But large long-term
epidemiological studies from various countries have proven that drinking coffee
is linked to a lower risk of insulin resistance and type-2 diabetes, Maor
writes. The proposed mechanisms are the suppression of the absorption of glucose
and of the glucose 6 phosphatase system responsible for the production of
glucose by the polyphenols in the coffee, as well as an increase in the level of
magnesium in the blood, weight loss and metabolism caused by the
caffeine.
Organic compounds called diterpenes raise the level of blood
cholesterol, but apparently phenols (another type of organic chemical compound
called carbolic acid) in coffee neutralize this influence and even raise the
level of high-density lipoprotein (HDL or “good cholesterol”).
This means
that the lower the amount of diterpenes in the coffee (as in filter and instant
coffees), the higher the amount of the phenols. But the effect on cholesterol
levels is very positive.
A number of studies have shown that drinking
coffee raises the level of homocysteine in the blood. Homocysteine is a natural
amino acid that, when at elevated levels, increases the risk of heart attacks,
strokes, blood clot formation and possibly Alzheimer’s
disease.
Short-term hypertension studies lasting one to 12 weeks showed
that caffeine raises blood pressure significantly. However, long-term
epidemiological research shows that there is no rise in blood pressure when
drinking three cups a day or less. Some have even found a protective effect
against increased hypertension, especially in women. Apparently, people’s bodies
get used to the caffeine over the long term and minerals, vitamins, polyphenols
and fibers in coffee neutralize the caffeine effect.
Caffeine may also
slightly reduce weight because caffeine raises the metabolism rate, while
polyphenols minimize the accumulation of abdominal fat and fat in the liver.
Decaffeinated coffee also reduces dental cavities and gum diseases.
There
is an inverse relationship between coffee drinking and Parkinson’s and
Alzheimer’s diseases and dementia, the author writes. The effect was more
powerful in men than in women not receiving hormone replacement therapy during
menopause. Caffeine is believed to have a protective effect against toxicity of
damaged brain cells. Statistical analysis shows coffee drinking reduces the risk
of suicide as it improves psychomotor function, increases vitality and
alertness, reduces fatigue and improves wellbeing. It can also minimize the risk
for colorectal cancers and other malignant growths, liver cirrhosis, fibrosis
and tumors.
In any case, consult your personal physician before deciding
to drink considerable amounts of coffee.
As for limitations on coffee
consumption, more than three cups (300 milligrams of caffeine) daily are
generally not recommended.
Women who are pregnant or or have difficulty
getting pregnant should limit themselves to three cups. It’s almost impossible
to get caffeine poisoning, as this would mean drinking 50 cups or more a day,
Maor writes.
Coffee drinking does not affect breast-feeding babies.
Children should not get more than 2.5 milligrams of caffeine per kilo of body
weight per day, and the elderly should not consume an unlimited amount. Caffeine
could interact with medications and may reduce body mass in very thin
people.
Maor concludes the article by saying that consumption of up to
three cups a day by adults is safe – whether it is caffeinated or decaffeinated
– and offers health advantages as well as the ability to reduce the risks for
certain diseases.
Rx for Readers welcomes queries from readers about
medical problems. Experts will answer those we find most interesting. Write Rx
for Readers, The Jerusalem Post, POB 81, Jerusalem 91000, fax your question to
Judy Siegel-Itzkovich at (02) 538- 9527, or e-mail it to [email protected],
giving your initials, age and place of residence.
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