Latex-food allergy

I don't have food allergies, nor an allergy to latex (that I'm aware of), but allergies are problems for others. I saw this in my newsletter from George Mateljan, World's Healthiest Foods website. His articles are long and detailed, and he carefully cites his sources in major, peer-reviewed journals (at the website). I personally have not studied this, but found the information interest--and didn't know trees had stress mechanisms.

"The only commercial source of latex in the marketplace is Hevea brasiliensis, the genus and species of rubber tree native to South America. When the gene stock for this tree was transported by the British to Asia, this tree began to express more of its "defense proteins" in response to the abrupt stress of a non-native environment. Included in these defense proteins were chitinase enzymes.

When rubber trees are tapped for their sap, which in turn gets processed into latex, some of these chitinase proteins get carried over into the latex. One particular 3-dimensional section of these proteins is a fairly common trigger of antibody reactions in humans. This immune system reaction to a section of the chitinase protein constitutes a latex allergy.

Certain foods have what is called a "Hevea-like" domain in their proteins. In other words, they have a 3-dimensional section of their proteins that is identical to the 3-dimensional section found in the chitinase proteins of latex. The existence of this identical spot allows for cross-reactivity between latex and certain foods. This cross-reactivity is called latex-food allergy, or latex-food syndrome. The primary foods associated with latex-food allergy are: avocado, kiwi, banana, and chestnuts and to a lesser degree, hazelnuts, peanuts, walnuts, almonds, passion fruit, strawberry, apple, fig, grapefruit, watermelon, pineapple, cherry. Pear, peach, mango, tomato, carrot, celery, sweet pepper, tomato, spinach, coconut, and paprika have at times also been associated with latex-food allergy.

We are not aware of any genetic modifications for the above food list that increase their Hevea-like protein domains. Although genetic modifications of food do introduce new proteins into those foods, we have not seen any research suggesting that these new proteins have any connection with latex cross-reactivity."