People with celiac disease have reported anxiety about ingesting gluten through a kiss, but a new study concludes that they can indulge without worry — even if their partner just had a gluten-filled snack, according to a study to be presented today at Digestive Disease Week® (DDW) 2025 . To be extra safe, the study recommends drinking water before smooching.
"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, PhD, assistant professor of nutritional medicine at Columbia University. "The advice we gave about kissing and celiac disease was based on precaution and assumptions. We were using our best judgment. I felt it was important to do research to see if there was any actual risk."
Researchers recruited 10 couples, each with one partner who has celiac disease, for a two-part study. In each session, the non-celiac partner ate 10 saltine crackers, and then the couple kissed for 10 seconds. In one session, the partners waited five minutes before the kiss, and in the other, they drank 4 ounces of water before kissing. In both situations, researchers found that the gluten transfer, which was measured in the saliva of the partner with celiac disease, was minimal in the majority of participants.
Although gluten was still found in saliva after kissing a partner who had consumed gluten and then had a glass of water, in all cases the amount was less than 20 parts per million, the level allowed in gluten-free products, which is considered safe.
Celiac disease, an autoimmune disorder, affects 1% of the population and is typically marked by digestive issues, including abdominal pain, indigestion, and diarrhea. For patients with celiac disease, gluten ingestion causes intestinal damage even if it does not cause immediate symptoms.
Understanding how gluten transfers through kissing could also be useful to people with non-celiac gluten sensitivity who experience symptoms like bloating, fatigue, or brain fog after exposure to gluten.
"For clinicians, we can now say to patients, 'You don't have to go to extreme measures,'" Dr. 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."
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