14 DAY TRIAL // Doctors say that a cup of wine per day is pure health. But sometimes just one cup can send you to hospital and it's not because of alcohol abuse.
A Spanish team has found that wasp venom in wine and grape juice seems to be the cause of wine poisoning, severe allergies induced by small quantities of ingested wine. The venom can enter the wine from wasps accidentally smashed along with the grapes during their initial processing for winemaking.
The team led by Alicia Armentia of the Rio Hortega Hospital in Valladolid, Spain, tackled five cases of patients who had developed severe allergies after drinking either wine or grape juice. Three subjects had facial flushing and swollen lips, while another patient experienced asthma-like symptoms.
The most severe case was that of a patient that developed anaphylactic shock, a whole-body allergic reaction that can induce death as heart and breathing stop, the same reaction as if you're stung by a swarm of bees. The patients were successfully treated, but the team wanted to find the cause of this type of poisoning.
An array of tests eliminated the most obvious suspect factors, like egg white, added sometimes to clarify the wine and decrease harshness and grape extract. When the researchers investigated the patients' blood, they detected antibodies typical for a recent bee or wasp sting, but none of them had experienced that.
Then the team compared for allergic responses red grape juice to the white one, but also fresh wine and three aged wines, coming from various vineyards. Both types of juice and the freshly processed wine induced allergic reactions in blood samples coming from the treated subjects.
More detailed chemical investigation encountered traces of venom coming from yellow-jacket wasps, not from honey bees, in the beverages.
"It's likely the insects fell into the grape juice when the grapes were pressed," said Armentia.
"Wasps abound on grapes in late summer. They will come to anything that's overripe, because they're running out of food by this time of year," explained Lee Townsend, an entomologist at the University of Kentucky in Lexington, Kentucky, US.
The aged wines did not contain venom, because like any other protein, it breaks down in time as the wine matured.
"Even a few weeks' aging probably breaks down the venom enough that the risk of a dangerous allergic reaction is minuscule-but if they want to be on the safe side, people with bee and wasp allergies may want to avoid drinking freshly made wine," warned Armentia.