Can Sharing a Kiss Lead to Gluten Transfer?

TOPLINE:

People with celiac disease shouldn’t worry too much about sharing a kiss with someone who just ate food containing gluten, a small study found.

METHODOLOGY:

• Researchers conducted a cross-sectional study with 10 couples — one partner with celiac disease and one without.
• To test variations in gluten content in saliva, the partner without celiac disease received a gluten load (10 crackers with 59,107 ppm or 590 mg gluten) and provided a saliva sample after four different protocols: After waiting 5, 15, and 30 minutes, and after immediately drinking 4 oz of water without waiting.
• There were two protocols to test gluten transfer via kissing: Waiting 5 minutes after gluten ingestion and then kissing and drinking 4 oz of water after gluten ingestion and then kissing without waiting. The couples were instructed to kiss with an open mouth for at least 1 minute, involving the tongue and saliva transfer.
• In the two kissing protocols, saliva was collected from the partner with celiac disease immediately after the kiss.
• Urine was tested for gluten absorption each evening and the morning after each kissing exposure.

TAKEAWAY:

• Gluten was detectable in the saliva of the partner without celiac disease in all protocols, though not at worrisome levels, according to the authors.
• Levels of gluten for the participants with celiac disease varied from < 5 ppm to 153.9 ppm; however, only two exposures resulted in levels > 20 ppm.
• One positive urine test was found in the evening the day of a gluten exposure; the saliva concentration in the partner with celiac disease was 153.9 ppm; all other urine tests were negative.
• Participants with celiac disease reported no symptoms at 6 and 12 hours after the kiss.

IN PRACTICE:

“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,” the lead author said in a press communication.

SOURCE:

Anne Lee, PhD, assistant professor of nutritional medicine at Columbia University, New York City, presented the study at Digestive Disease Week (DDW) 2025.

LIMITATIONS:

This was a small study, not yet published, and without data in the abstract on patient demographics, characteristics, and other factors that may have influenced the findings.

DISCLOSURES:

No funding information was provided. Lee disclosed no conflicts of interest.