Since coffee is widely consumed worldwide, it is of critical importance to know its effects on the first organs of the body with which it comes in contact during consumption, i.e., the gastrointestinal tract. Surprisingly, research devoted to this aspect remains scarce. A new review of previous studies, published this week in the journal Nutrients, shows that coffee intake stimulates gastric, biliary, and pancreatic secretions, seeming to favor the first steps of the digestive process.
Dr. Astrid Nehlig reviewed the state of the art on the consequences of drinking coffee at the different levels of the gastrointestinal tract. Image credit: Sci-News.com.
“The influence of coffee on digestive processes has been known for a long time, and drinking coffee after a meal has become a habit for most of us,” said study author Dr. Astrid Nehlig, a researcher of the French National Institute of Health and Medical Research and a scientific consultant at the Institute for Scientific Information on Coffee.
“Indeed, coffee is considered to favor digestion by acting on the acid production of the stomach, on bile and pancreatic secretion, and on colon motility.”
“In our review, we consider the effects of coffee ingestion on the organs composing the gastrointestinal tract, which are the first organs with which coffee and its large diversity of components come into contact after ingestion.”
In a systematic review, Dr. Nehlig analyzed data from a total of 194 studies on coffee consumption.
The findings suggest that moderate coffee consumption (3-5 cups per day) was not found to generate harmful effects on the various organs of the digestive tract.
“Two areas of particular interest emerging from the research are the association between coffee and a reduced risk of gallstones and the evidence linking coffee consumption with a reduced risk of pancreatitis, although more research is still needed,” Dr. Nehlig said.
“On its journey through the gastrointestinal tract, coffee has three main impacts,” she explained.
“Coffee is associated with gastric, biliary and pancreatic secretions, all necessary for the digestion of food. Coffee was found to stimulate production of the digestive hormone gastrin; and hydrochloric acid, present in gastric juice — both of which help break down food in the stomach. Coffee also stimulates the secretion of cholecystokinin, a hormone that increases the production of bile, also involved in digestion.”
“Coffee appears to be associated with changes in the composition of gut microbiota. In the reviewed studies, coffee consumption was found to induce changes in the composition of the gut microbiota, mainly at the population level of Bifidobacteria, a ubiquitous inhabitant of the gastrointestinal tract.”
“Coffee is associated with colon motility — the process by which food travels through the digestive tract. The data suggest that coffee may stimulate motility in the colon as much as cereals, 23% more than decaffeinated coffee or 60% more than a glass of water1 and it may be linked to a reduced risk of chronic constipation.”
The latest research also strongly supports the protective effect of coffee against liver diseases, including hepatocellular carcinoma — one of the most common types of liver cancer.
Despite the evidence to suggest coffee consumption may support with the first stages of digestion, most data did not support the finding that coffee had a direct effect on gastro-oesophageal reflux. Instead, this is a combined or additive effect of other risk factors such as obesity and a poor diet.
“Contrary to some assumptions, coffee consumption is not overall linked to bowel or digestive problems,” Dr. Nehlig said.
“In some instances, coffee has a protective effect against common digestive complaints such as constipation.”
“Emerging data also indicate there may be an association with improved levels of gut bacterial groups such as Bifidobacteria which have recognized beneficial effects.”
“Although additional data will be needed to understand coffee’s effects throughout the digestive tract, this is an extremely encouraging place to begin.”
_____
Astrid Nehlig et al. 2022. Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update. Nutrients 14 (2): 399; doi: 10.3390/nu14020399
