Some kiwi varieties may be less allergy-inducing

With kiwifruit becoming ubiquitous in grocery stores worldwide, reports of allergic reactions to the fruit have also increased. But some varieties may be less likely than others to trigger allergies, a small study suggests.

In tests of 37 adults with kiwi allergies, researchers found that certain cultivars of the fruit - including the "gold" variety - tended to be less allergenic than the common deep-green variety known as Hayward.

The findings, reported in the Journal of Allergy and Clinical Immunology, raise the possibility that people who avoid kiwi because of allergies might be able to reintroduce the fruit into their diets. Larger studies are needed, however, before they can be given the green light.

The kiwifruit, native to southern China, was once considered an "exotic" fruit, but since the 1970s its availability and popularity has increased worldwide. With that wider consumption has come an increase in incidents of allergic reactions to kiwi.

Symptoms of kiwi allergy can include tingling, itchiness and inflammation in the mouth and throat, skin rash, stomach pain and vomiting, and even severe reactions like breathing problems or a sudden drop in blood pressure.

Recent studies from Sweden, Finland and France indicate that kiwi has become one of the top-10 sources of food allergies in those countries, noted Dr. Karin Hoffmann-Sommergruber, an associate professor at the Medical University of Vienna, in Austria.

For the current study, Hoffmann-Sommergruber and her colleagues looked at whether different kinds of kiwi vary in their tendency to provoke immune system reactions and symptoms in people with allergies to the fruit.

They assessed six kiwi varieties, including Hayward, the most commonly available cultivar, with the familiar medium-brown skin and bright-green flesh; and Summer 3373, a variety in the same kiwi "species" as Hayward but with light-green flesh. The latter came to the market more recently but its availability is growing.

The other tested kiwifruits included Hort 16A, marketed as "Zespri Gold" and the most widely available golden-fleshed variety; Jintao, a golden variety newer to the market; and two varieties of a kiwi species called Eriantha expected to come to market in the next 10 to 20 years; they are smaller and lighter-skinned than other kiwi varieties and have deep-green flesh.

All of the study participants underwent skin testing, in which a thin needle was first injected in the fruit and then into the participant's skin to gauge the immune system reaction. In general, the researchers found, the Hayward kiwi triggered the most significant skin reactions, while the lighter-green Summer and gold Hort 16A varieties garnered the mildest reactions.

A subgroup of participants also underwent food-challenge tests, in which they were gradually given small amounts of the Hayward, Summer and Hort varieties under medical supervision.