Can gluten be passed down through kissing?

By Stephen Beech

Gluten can be passed on through kissing, according to a new study.

But the risk is "low and easily reduced" – by drinking a glass of water before locking lips - for people with celiac disease, scientists say.

For the one in 100 people living with celiac disease, the fear of gluten exposure can extend beyond food - even into moments of intimacy.

But American researchers say the new study offers "reassuring" news.

Dr. Anne Lee, of Columbia University, New York City, said: "While gluten can be transferred through kissing, the amount transferred is typically very small and can be reduced to safe levels with a simple step."

She explained that for people with celiac disease, ingesting gluten - even without immediate symptoms - can cause intestinal damage, requiring lifelong adherence to a strict gluten‑free diet.

Previous studies have shown that fear of accidental exposure can lead to anxiety, hypervigilance, and social avoidance, particularly around dating and relationships.

More from this section

Creatine goes mainstream with Gen Z and millennials

Massive eye drop recall reflects ongoing issues with manufacturing and FDA inspection

Paying cash for healthcare: Can it save you money?

In the first study to quantify gluten exposure through kissing, researchers examined gluten transfer in 10 couples, each consisting of one partner with celiac disease and one without.

The two‑part study, published in the journal Gastroenterology, assessed whether gluten consumed by the non‑celiac partner could be transferred through an open‑mouth kiss involving saliva exchange - and if so, whether the amount posed a "meaningful" risk.

Across two kissing protocols, the non‑celiac partner ate 10 Saltine crackers and then kissed their partner with celiac disease.

In one scenario, partners waited five minutes before kissing. In the second, conducted on a separate day, the non‑celiac partner drank four ounces of water immediately after eating the crackers and then kissed their partner.

Lee, an expert on nutritional management of celiac disease, said: "Gluten levels in saliva were below 20 parts per million (ppm) in 90% of all samples, the threshold considered safe for gluten‑free products.

"Only two of 20 kissing exposures exceeded 20 ppm, and even in those cases, the total amount of gluten ingested was negligible."

She added: "No saliva samples exceeded 20 ppm when the non‑celiac partner drank four ounces of water before kissing.

"In fact, 60% of saliva samples after drinking water contained no detectable gluten at all."