Why some people are allergic to wine

A lot of us like a nice glass of wine at the end of the day, but for around 500 million people in the world, that's not so much fun, as they have an allergy to wine. It's apparently a bit like having a hayfever attack, with itchy eyes and sneezing. Now a group from the University of Southern Denmark have found out exactly what it is in the wine that makes these people react to it.

It's a type of molecule called a glycoprotein, which is also what causes other allergic reactions like those to pollen and dust mites. These are molecules made up of sugar and protein molecules joined together and they're really important to life - they're found in our cell membranes, some important hormones are glycoproteins, and they also play a key role in immune response. The kind of glycoproteins on the outside of an invading pathogen like a bacterium for example help the immune system to identify it.

So the team led by Guiseppe Palmisano tested an italian chardonnay using a mass spectrometer to see if there were glycoproteins present that might be causing these reactions. They identified 28 different glycoproteins in the wine, contributed by both the grapes and the yeast used to make the wine. Many of the glycoproteins from the grapes were very similar in structure to ones known from other plants and fruit that are known to cause allergic reactions, and it's the structure of the glycoprotein that is important in it being an allergen or not.

So the team suggested that this could be a step towards creating low-allergenic wines, although this would probably be a fair way off as the very glycoproteins that can cause these reactions are essential for the palate and the structure of the wine, and it's not clear exactly which of the glycoproteins present might be responsible, so there's still work to be done there...