People with celiac disease can safely kiss their partners who have just ingested gluten, according to the results of a new study — though researchers recommend drinking some water first.
The analysis, whose findings were presented Monday at Digestive Disease Week 2025, sought to answer a question that its authors say is frequently asked but minimally researched.
“Everyone worries about whether gluten is getting into their food at a restaurant, but no one really looked at what happens when you kiss afterwards,” said Anne Lee, a Columbia University assistant professor of nutritional medicine who presented the data.
“The [previous] advice we gave about kissing and celiac disease was based on precaution and assumptions,” Lee added in the statement. “We were using our best judgment. I felt it was important to do research to see if there was any actual risk.”
Celiac disease is an autoimmune disorder that affects approximately 1 percent of the population, triggered by the consumption of gluten found in bread, pasta, soy sauce and other foods.
Symptoms vary, but they can include gastrointestinal issues such as indigestion, abdominal pain and diarrhea, as well as some nondigestive symptoms including fatigue, joint pain and neurological issues. The disease can also cause long-term damage to intestines without resulting in immediate symptoms.
The study looked at 10 couples that each included one individual with celiac and one without.
In the first part of the study, the person without celiac had 10 saltine crackers, waited five minutes, then kissed their partner for anywhere from 10 seconds to a minute. In part two, the person repeated those steps, but drank 4 ounces of water instead of simply waiting before smooching.
Researchers measured the results through surveys, urine and saliva tests of the partner with celiac to detect for the presence of gluten.
In both parts, the majority of couples reported the gluten found in the saliva of the individual with celiac disease was under the maximum level allowed for food products to be marked gluten free and considered safe: 20 parts per million.
In the first part of the survey — without any water — two individuals reported gluten above that threshold, one of whose urine test also came back positive, but no symptoms were reported in the surveys.
When participants drank 4 ounces of water before the kiss, all participants reported gluten levels under 20 ppm.
“For clinicians, we can now say to patients, ‘You don’t have to go to extreme measures,’” Lee said.
“Patients with celiac disease can be more relaxed, knowing that the risk of gluten cross-contact through kissing a partner who has consumed gluten can be brought down to safe levels if food is followed by a small glass of water,” she added.
