Coffee, Heartburn and Your Stomach
Americans love the taste, aroma, and even the health benefits of coffee. What some people experience but can do without are the heartburn and associated stomach problems.
Approximately 83 percent of Americans drink coffee, says the National Coffee Association (NCA), and the latest figures from the NCA is that 61 percent consume it daily. Those same current figures show that 18 percent of American adults are downing espresso-type drinks daily compared with 13 percent last year.
Heartburn culprits in coffee?
Several years ago, experts at the University of Vienna and the Technische Universitat Munchen conducted a study and reported that substances in coffee such as caffeine, catechols, and N-alkanoly-5-hydroxytryptamides appear to trigger chemical changes associated with a rise in the production of stomach acid. The study was done using regular, decaffeinated, mild, stomach-friendly, and dark-roast brews.
According to the researchers, a combination of substances, and not a single factor, was associated with stomach irritation and heartburn. On a promising note, they also said that an agent called N-methylpyridium (NMP) seemed to block the production of hydrochloric acid.
NMP is produced when coffee beans are roasted, and since darker roasted coffees such as espresso have higher levels of NMP, such brews could be less irritating (be associated less with heartburn) than lighter brews. Another factor is that the amount of NMP in coffee can vary depending on the roasting process and the bean variety.
Before continuing any further, let’s clarify the relationship between heartburn and GERD (gastroesophageal reflux disease). Heartburn is a burning sensation behind the breastbone that can rise in the upper abdomen and travel to the chest. It is a typical symptom of GERD and may be caused by various factors.
Heartburn, along with acid regurgitation and painful swallowing (odynophagia), are highly specific for GERD. Gastroesophageal reflux occurs when your stomach contents rise up into your esophagus. When stomach acid touches the lining of the esophagus, it can cause heartburn, also called acid indigestion.
Coffee, heartburn and stomach problems
Nearly 20 percent of people who drink coffee experience heartburn and stomach irritation. Whether you are among this population or not, the findings of several studies are enlightening. For example:
One study looked at the frequency of heartburn produced by a variety of beverages, including coffee, oolong tea, carrot juice, soft drinks, and soju (a rice liquor). Both coffee and soju were the most likely to produce heartburn while tea and carrot juice were the least likely. Decaffeinated coffee was significantly less associated with heartburn than was regular coffee.
A larger and more recent study looked at the association between drinking coffee and four conditions associated with stomach acid: gastric ulcer, duodenal ulcer, reflux esophagitis, and non-erosive reflux disease. A total of 8,013 individuals were involved in the evaluation, of which 5,451 were coffee drinkers and 2,562 were not.
After allowing for factors such as smoking, alcohol use, body mass index, age, gender, and Helicobacter pylori infection status (bacteria associated with ulcers), the investigators made the following comments:
- Coffee consumption was not significantly associated with any of the four conditions
- It is possible that coffee has some preventive effects that “might outweigh the risks of increased gastric acid secretion: relaxing effect, antioxidant effect, phytochemical effect, and so on”
- An insufficient number of epidemiological studies involving coffee consumption and GERD have been conducted
In the World Journal of Gastroenterology, a team reported on the results of a decade-long population-based study that involved 2,000 adults who were questioned in 1996 and again in 2006. Although this study did not identify coffee or any specific food or beverage as being associated with heartburn, it did highlight a few items of interest. Do any of them ring true for you?
- 20 percent of the individuals said food or beverages were the cause of their heartburn very often
- One third of those experiencing heartburn said it worried or scared them to have heartburn every week
- Half of the people with heartburn said it significantly affected their ability to sleep
- 75 percent of heartburn sufferers said the condition made them irritable
According to one source (Journal of Gastrointestinal Surgery), 25 to 40 percent of Americans experience GERD at some point in their lives, and up to 10 percent live with it on a daily basis. Heartburn, GERD, and other stomach-acid conditions affect countless millions of people, and coffee may or may not be a cause.
Why can one person drink several cups of coffee every day and never have heartburn or GERD while another could experience these stomach acid problems after just half a cup? As with most things in life, there are many factors to consider, including each person’s unique biochemical and genetic makeup as well as lifestyle. It appears the experts are still exploring these questions, possibly over a cup of java.
Herbella FA et al. Gastroesophageal reflux disease and obesity. Pathophysiology and implications for treatment. Journal of Gastrointestinal Surgery 2007 Mar; 11(3): 286-90
Kim YK et al. The relationship between the popular beverages in Korea and reported postprandial heartburn. Korean Journal of Gastroenterology 2010 Feb; 55(2): 109-18
National Coffee Association USA, 2013 and 2014 figures
Olafsdottir LB et al. Natural history of heartburn: a 10-year population-based study. World Journal of Gastroenterology 2011 Feb 7; 17(5): 639-45
Shimamoto T et al. No association of coffee consumption with gastric ulcer, duodenal ulcer, reflux esophagitis, and non-erosive reflux disease: a cross-sectional study of 8,013 healthy subjects in Japan. PLoS One 2013 Jun 12; 8(6): e65996