March 6, 2006 (Miami Beach) -- A kiss is not just a kiss -- at least for people with food allergies. So say researchers who found that people with peanut allergies may be putting themselves at risk of potentially life-threatening allergic reactions if they kiss someone who has recently eaten peanuts.
And there's no quick fix: Brushing your teeth or chewing gum after the nutty meal won't help, the study shows. In fact, the only real solution is skipping the nuts altogether or at least waiting a few hours before kissing -- not always easy for young teens in love.
"The best advice to the partner of a peanut-allergic person is to avoid peanuts as well," says researcher Jennifer M. Maloney, MD, a fellow in allergy at Mount Sinai Medical Center in New York City. "If you can't do that, the next safety strategy is to wait several hours and eat several meals without peanuts before kissing your partner."
3 Million Americans Have Peanut Allergies
Approximately 11 million Americans suffer from food allergies, with 6.5 million being allergic to seafood and 3 million allergic to peanuts or tree nuts, such as walnuts. As many as 200 of them die each year, according to Food Allergy & Anaphylaxis Network.
Last year, a Quebec, Canada, coroner initially attributed the death of a 15-year-old girl with peanut allergy to a kiss from her boyfriend, who had snacked on peanut butter. The Canadian coroner has since reversed his conclusion. But "this does not negate the importance of research showing that kissing, particularly passionate kissing, can cause severe, life-threatening reactions in people with food allergies," says Suzanne S. Teuber, MD, a food allergy expert at the University of California at Davis.
Peanut Allergen Lingers for Hours
For the new study, Maloney and colleagues first measured how much peanut allergen was in saliva following a meal as well as how long it stuck around.
Ten people ate sandwiches packed with 2 tablespoons of either creamy or crunchy peanut butter. In saliva samples taken just five minutes later, peanut allergen could not be detected in three of the 10 people, a finding that surprised Maloney. "Maybe they didn't chew well," she says.
By an hour later, no allergen could be detected in six of the other seven volunteers. But in the final person, the saliva wasn't allergen-free until 4.5 hours later, Maloney says.
Then, the researchers wanted to determine if simple measures such as brushing your teeth for two minutes, rinsing your mouth via the "swish and spit" method, or chewing gum after the meal would drive the peanut allergen out of saliva more quickly.
"But no intervention really removed it from saliva uniformly," Maloney tells WebMD. "You won't be safe if you think your partner can just brush his teeth or chew gum."
Teuber notes that although Maloney studied people with peanut allergies, the same advice applies to other people with other food allergies.