How that after-eating coffee affects you
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
