Cooked Carrots Can Cause Allergies

Consumption of cooked carrots can trigger an allergic response, according to a new study by the University of Bayreuth.

It was previously believed that consumption of raw carrots resulted in allergic reactions; however, the new study shows that cooked carrots also have the same effect.

The study is published in the journal Molecular Nutrition & Food Research.

‘Consumption of cooked carrots can trigger an allergic response similar to the consumption of raw carrots. The carrot allergen Dau c 1 is harmless at high temperatures, but it regains its natural structure once the temperature drops. Thus, people who are allergic to raw carrots should also avoid eating cooked carrots and carrot extract.’

The natural carrot contains an allergen called Dau c 1. This allergen is a mixture of several structurally similar proteins called isoallergens.

The isoallergens were produced individually in the laboratory in bacteria. The protein mixture of Dau c 1 and the individual isoallergens was examined at temperatures up to 95 degree Celsius.

The researchers wanted to observe the changes in the structure of Dau c 1 and isoallergens upon increasing and decreasing the temperature.

The researchers found that the natural mixture of Dau c 1 and almost all the individual isoallergens was still capable of causing allergies when they were cooled down to 25 degrees Celsius.

When heated, the carrots allergen assumes a harmless structure. However, it largely regains its natural structure once the temperature drops.

Antibodies present in the organism of allergy patients will still trigger allergic reactions, although it has been heated. However, the allergic reaction is generally maintained; it may be less pronounced after heating in some cases.

"This is the first time that the Dau c 1 isoallergens have been subjected to such an extensive series of tests. The separate examination of the structurally similar molecules was particularly important to us to determine which of the isoallergens trigger immune reactions under the tested conditions," says Thessa Jacob.

The different tests showed that the structural stability of the carrot allergen does not depend on temperature alone.

Acidity also plays a role. At the pH value of 3, which is typically present in the stomach, some epitopes continue to exist despite previous heating.

Epitopes are the molecular substructures by which the immune system recognizes the respective allergen, allowing an allergic reaction to occur.

Magnetic resonance spectroscopy (NMR) and CD spectroscopy were mainly used for structural investigations of the Dau c 1 isoallergens.

"The risk of allergy patients developing an allergic reaction arises not only when eating freshly cooked carrots or canned carrots. It also arises when carrot extract is added to food," says Thessa Jacob M.Sc.



Source: Medindia