Coming Soon: A Low-Heartburn Coffee?

Darker roasts have fewer irritants than lighter brews, researchers find

For millions of coffee-lovers with delicate stomachs, scientists may have found a way to enjoy an eye-opening cup of java without gastrointestinal discomfort.

European researchers studying stomach-irritating chemicals in coffee have unexpectedly found one that actually inhibits acid production in the stomach.

"The major import of our work is that it provides scientific evidence that you can produce a more stomach-friendly coffee by varying the processing technology," said study author Veronika Somoza, professor and chair of the Research Platform of Molecular Food Science at the University of Vienna, Austria.

The finding offers the promise that coffee makers can produce a blend that will be easier on the tummy, Somoza said.

The results were to be presented Sunday at the American Chemical Society's annual meeting in San Francisco.

The scientists looked at coffee's effect on human stomach cells using a variety of preparations, including dark-roast, regular roast, decaffeinated and stomach-friendly. Instead of one single element, they identified a mixture of compounds -- caffeine, catechols and N-alkanoly-5-hydroxytriptamides -- as the chemicals in coffee that promote the production of stomach acid.

But a fourth chemical, N-methylpyridinium, which is more common in dark roasts, such as espresso and French roast blends, was found to inhibit acid.

N-methylpyridinium is a product of the roasting process itself, resulting in dark roasts that are less likely than lighter ones to cause stomach irritation, according to the research.

Whether the findings will translate to human coffee drinkers remains unclear. The authors hope to conduct tests with human coffee drinkers this year.

Dr. Joseph Vinson, a professor of chemistry at the University of Scranton in Pennsylvania who has studied the antioxidant properties of coffee, said the study suggests the possibility of a less troublesome brew.

"Cell studies can be legitimate. They can lead to human studies that will say the same thing," said Vinson. "She [Somoza] has figured out a research approach that is one way to do it, and it's a question of whether it is relevant to the human realm."

Vinson predicted it will be.

"There's more than enough data [in the study] to make it interesting," said Vinson. "There can be this special coffee that doesn't bother you."

The potential market for a kinder, gentler coffee is huge. About 40 million people in the United States alone avoid java, often because of acid reflux disease, a common stomach problem for coffee drinkers, according to background information from the American Chemical Society. Stomach-friendly coffees are already on the market, but some doctors don't recommend them for people with acid reflux, which pushes stomach contents back up the esophagus, causing heartburn.

Among them is Dr. Anthony A. Starpoli, director of gastroesophageal research at St. Vincent's Catholic Medical Centers in New York City, who doesn't advise drinking decaffeinated coffee either.

"When you say you can have a little, it becomes a license to do whatever you want," said Starpoli about the advice he gives his patients. "I'm very strict about coffee," he added, because it causes serious stomach trouble for some.

The study suggests some balance of "good guys" and "bad guys" in coffee, and the process used to make it more stomach-friendly eliminates both, he noted. The study's identification of components causing problems for coffee drinkers is a valuable finding and supports his medical advice that some people should avoid drinking coffee entirely, he said.

"It shows a reason, and you always need to have a reason. At the end of the day, if you have significant acid reflux disease, you should not drink coffee," said Starpoli.

Many medications prevent acid reflux, and Starpoli believes they help. But he cautions against their overuse by folks who take them so they can have coffee, wine or other heartburn-inducing foods. The medicines can inhibit the acid that kills helpful bacteria, sometimes causing diarrhea and other serious problems, and can also become addictive, Starpoli said.

Production of a less-irritating coffee would be welcome news, because so many patients resist giving up their daily java, he said.

"It's almost a completely non-negotiable item for some of them," he said.

More information

There's more on acid reflux at the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.