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Coffee Drinking
No Longer So Controversial
Other Topics: Coffee
Emission Monitoring,
Coffee Challenge,
Coffee Revenue, Coffee
Licensing Package
Medical News Today
May 4, 2007
Although the American Society for Nutrition's popular
"controversy session" at Experimental Biology 2007 focuses
on the health effects of coffee drinking, panel chair Dr.
James Coughlin, a toxicology/safety consultant at Coughlin
& Associates, says that recent advances in epidemiologic
and experimental knowledge have transformed many of the
negative health myths about coffee drinking into validated
health benefits.
Indeed, panel co-chair Dan Steffen, who follows coffee and
health issues in the Scientific and Regulatory Affairs
group of Kraft Foods, note that the "controversy" is often
to educate a wider audience about this transformation in
understanding.
Coffee is among the most widely consumed beverages in the
world, and Dr. Coughlin says that the preponderance of
scientific evidence - some by the panelists - suggests
that moderate coffee consumption (3-5 cups per day) may be
associated with reduced risk of certain disease
conditions, such as Parkinson's disease. Some research in
neuropharamacology suggests that one cup of coffee can
halve the risk of Parkinson's disease. Other studies have
found it reduces the risk of Alzheimer's disease, kidney
stones, gallstones, depression and even suicide.
Dr. Coughlin and two distinguished researchers discussed
some of the benefits - and a couple of the remaining
increased risk factors (possible increase in blood
pressure and plasma homocysteine) at the Experimental
Biology meeting in Washington, DC.
Dr. Rob van Dam, an epidemiologist at the Harvard School
of Public Health and the Harvard Medical School, studies
the link between diet and the development of type 2
diabetes. Worldwide, an estimated 171 million persons have
diabetes, mostly type 2 diabetes, and an alarming increase
to 366 million persons is expected for the year 2030.
While increased physical activity and restriction of
energy intake can substantially reduce risk of type 2
diabetes, he believes insight into the role of other
lifestyle factors may contribute to additional prevention
strategies for type 2 diabetes.
In recent epidemiological studies in the U.S., Europe and
Japan, persons who were heavy coffee consumers had a lower
risk of type 2 diabetes than persons who consumed little
coffee. Interestingly, he says, associations were similar
for caffeinated and decaffeinated coffee, suggesting that
coffee components other than caffeine may be beneficial
for glucose metabolism.
Coffee contains hundreds of components including
substantial amounts of chlorogenic acid, caffeine,
magnesium, potassium, vitamin B3, trigonelline, and
lignans. Limited evidence suggests that coffee may improve
glucose metabolism by reducing the rate of intestinal
glucose absorption and by stimulating the secretion of the
gut hormone glucagon-like peptide-1 (GLP-1) that is
beneficial for the secretion of insulin. However, most
mechanistic research on coffee and glucose metabolism has
been done in animals and in lab tubes and therefore
metabolic studies in humans are currently being conducted.
Further research may lead to the development or selection
of coffee types with improved health effects.
Dr. Lenore Arab, a nutritional epidemiologist in the David
Geffen School of Medicine at UCLA, notes that the first
coffee controversy dates back 430 years when in 1570 some
monks petitioned the pope to condemn this drink, so
popular among Muslims. Pope Clement VIII, liking how it
kept the monks from falling sleep during mass, purportedly
blessed it instead. The rest, including the United States'
wholesale conversion to coffee following the Boston Tea
Party, is history.
In reviewing the latest epidemiologic literature on
cancers and coffee, Dr. Arab has found there to be close
to 400 studies of the associations between coffee
consumption and cancers various at various sites. The
earlier controversy with regard to colon cancer was based
on flawed analyses, she says. More thorough analyses and
the accumulation of evidence suggest no negative effect on
the incidence of colon cancer, and possible protective
effects for adenomas of the colon as well as for rectal
cancer and liver cancer. Mechanisms which might contribute
to a possible anticarcinogenic effect include reduction in
cholesterol, bile acid and neutral sterol secretion in the
colon, increased colonic motility and reduced exposure of
epithelium to carcinogens, the ability of diterpenes to
reduce genotoxicity of carcinogens, and lower DNA adduct
formation, and the ability of caffeic acid and chlorogenic
acid to decreased DNA methylation. In other cancers -
breast, ovarian, and prostate - the evidence is not
suggestive of either risk or protection. There are two
areas, says Dr. Arab, in which there is some evidence of
increased risk: leukemia and stomach cancer. The evidence
for the former is intriguing, for the latter
insubstantial. She concludes that a systematic review of
the newer data for liver, rectal, stomach cancer and for
childhood leukemia is due. |
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