Researchers debunk conventional wisdom

Contrary to popular belief, poinsettias are not toxic to people or animals, suicides do not increase over the Christmas holidays, and sugar does not make kids hyperactive. Also, Wales winning the rugby grand slam does not influence the death of popes, and douching with Coca-Cola is not an effective contraceptive method.

Those are some of the conclusions of reports in the British Medical Journal's annual Christmas issue, a compilation of the weird and lighthearted papers its editors accumulate over the year. In a related vein, a report in the journal Lancet details the curious case of a woman who fainted every time she ate a sandwich.

Drs. Christopher J. Boos and Howard Marshall, cardiologists at University Hospital Birmingham, treated a 25-year-old woman who suffered repeated fainting episodes, particularly when eating a sandwich or drinking a fizzy drink.

A full medical work-up showed her to be healthy overall, but the team ultimately diagnosed a condition called swallow syncope, which caused her heart to stop beating for as long as three seconds after some types of swallowing -- especially sandwiches, for no clear reason.

The woman was fitted with a pacemaker and has had no fainting episodes since, Boos and Marshall reported in the Lancet. They suspect that many other patients suffer the problem without being diagnosed.