A British woman who suffered from allergic reactions where her heart stopped beating when she ate sandwiches or drank carbonated beverages was fitted with a pacemaker to relieve the condition, the Birmingham Mail reported Tuesday.

Doctors in Birmingham, England told the newspaper the 25-year-old woman complained feeling “light-headed, occasionally nauseous, and suddenly and alarmingly unwell,” and had even fainted after consuming sandwiches or sodas since she was a teenager.

The woman, who did not want her name released, had not realized it was the food and drink causing her illness.

Medics diagnosed the condition and notified doctors after the woman’s latest allergic reaction, which occurred after she ate a sandwich.

To test the theory, doctors at the University Hospital Trust in Birmingham, England, gave the woman a sandwich. Cardiologists noticed electrical abnormalities in the woman’s heart immediately, which stopped beating for two seconds.

Dr. Christopher Boos, a cardiologist at University Hospital Trust, diagnosed the woman with swallow syncope, or a temporary loss of consciousness due to insufficient blood supply to the brain. The condition is usually caused by emotional stress, nerve stimulation or an immediate change in the position of the body or surrounding temperature.

In this woman’s case, the act of swallowing most likely stimulated a nerve, Boos said.

At a follow-up visit, doctors said she had not fainted since she received the pacemaker.

Click here to read more on this story from the Birmingham Mail.