From: Andy Soos, ENN
Published March 23, 2010 04:44 PM

The Perils of Coffee

Coffee starts the days of many people. With some stomach irritation can prevent proper enjoyment of the brew. Scientists have reported recently the discovery of several substances that may be among the culprits responsible for brewing up heartburn and stomach pain in every cup. Their report, presented at the 239th National Meeting of the American Chemical Society, included the counter-intuitive finding that espresso, French roast, and other dark-roasted coffee may be easier on the tummy because these roasts contain a substance that tells the stomach to reduce production of acid.

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The research could lead to a new generation of stomach friendly brews with the rich taste and aroma of regular coffee.

"This discovery is going to help a lot of people who suffer from coffee sensitivity," say Veronika Somoza, Ph.D. from the University of Vienna in Austria, and Thomas Hofmann, Ph.D. from the Technische Universit√§t M√ľnchen in Germany, who conducted the study.

Conventional coffee wisdom worries about the acidity of the coffee blend. Acidity is a term used in at least three overlapping ways in the world of specialty coffee. For the coffee aficionado, acidity is the dry, bright sensation that distinguishes fine high grown coffees from duller, low grown coffees. For these sophisticates, the brighter and more acid a coffee the better. But for many other coffee drinkers, acidity is a word for an upset tummy and an unpleasant astringent sensation that ruins a beverage they otherwise enjoy.

Estimates suggest that up to 40 million people in the United States alone either avoid coffee, or cannot drink as much as they like, due to stomach irritation. Some doctors think that chemicals in coffee cause the stomach to overproduce acid. Some coffee drinkers take antacids or drink decaffeinated coffee in an effort to reduce this effect. Others turn to a small but growing number of specialty coffee brews marketed as stomach friendly.

Obviously everyone has a different taste for their coffee. The causes of the stomach upset from coffee has not yet been sufficiently studied though the present research may help this cause. There may be other causes too such as stress or other ingredients such as the milk. Finally just plain too much may have a negative impact.

The processes used to produce stomach friendly coffee also can potentially reduce the amount of healthful substances in the coffee, including some that scientists have linked to benefits such as protection against diabetes and heart disease. In addition, the processing can affect the robust taste and smell of coffee which is so attractive to some.

To study the irritants in coffee, the scientists exposed cultures of human stomach cells to a variety of different coffee preparations, including regular, dark roast, mild, decaffeinated, and stomach friendly. They identified several substances that appeared to trigger chemical changes associated with increased acid production. These substances include caffeine, catechols, and other ingredients.

"Our data show, for the first time, that caffeine, catechols and N-alkanoly-5-hydroxytryptamides are those coffee components that stimulate molecular mechanisms of stomach acid secretion in human stomach cells," Somoza said. Most of them are indeed removed by steam or solvent treatment of the raw coffee bean. We found out there's no single, key irritant. It is a mixture of compounds that seem to cause the irritant effect of coffee."

The scientists unexpectedly found that one of the coffee components, N-methylpyridium (NMP), seems to block the ability of the stomach cells to produce hydrochloric acid and could provide a way to reduce or avoid stomach irritation. Since NMP is generated only upon roasting and not found in raw coffee beans, darker roasted coffees contain higher amounts of this stomach friendly coffee ingredient. Dark roasted coffee can potentially contain up to twice as much of the ingredient as light roasted coffees, but its levels can vary widely depending on the variety of coffee bean and the roasting method, Somoza noted.

Until the studies are done coffee drinkers will have to try the various coffee blends and find the one most palatable for them.

For further information: http://www.eurekalert.org/pub_releases/2010-03/acs-bua030810.php

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