Blueberry is a food which may result in allergy symptoms in sensitised individuals.

Blueberry Allergy Test: Allergen Exposure

The name blueberry can describe any one of a number of related shrubs, with over 50 species in the same genus. Similar species include cranberry, lingonberry, bilberry and huckleberry, the latter of which is often erroneously used as a term for blueberry as well.

The two main varieties are V. angustifolium, the lowbush blueberry and V. corymbosum – the highbush blueberry. The former can reach up to 5 metres in height, while the latter grows to a maximum height of one metre and is hardier.

Blueberries grow wild in temperate to cold climates including Canada, New England, Great Britain and New Zealand, and are also cultivated in these regions. They are not commercially cultivated on a large scale however, and as a result are relatively expensive when compared to other small fruit.

They are generally eaten raw, or added to baked goods such as cakes or muffins. Blueberries may be dried like currants, and their dried leaves can be used to make tea. When eaten fresh, the blueberry has a mild laxative effect, however the dried fruit is astringent and can be used to treat diarrhoea and cystitis.

Blueberry tea is strongly astringent, diuretic, tonic, and an antiseptic for the urinary tract, as well as being said to benefit patients in pre-diabetic states, or even to remedy diabetes.

Green and blue dyes are obtained from the leaves and fruit respectively, and used in the colouring of fabrics, as well as the manufacture of ink in the latter case. Blueberry juice can also be used as an oral contrast agent in upper abdominal magnetic resonance imaging (MRI).

Blueberry Allergy Test: Allergen Description

While no allergens from the blueberry plant or fruit have yet been characterised, it has been shown to contain a lipid transfer protein.

Blueberry Allergy Test: Potential Cross-Reactivity

To date, there has been no documented instance of cross reactivity. However, there may be cross-reactivity with other fruits in the genus Vaccinium. This includes cowberry, foxberry, mountain cranberry, rock cranberry, lingonberry all of which are found in Europe, particularly Scandinavia in preserves and beverages.

Additionally the lipid transfer protein found in blueberry is cross-reactive with the LTPs found in a range of foods, in particular stone fruits, such as peach, cherry and apricot. Raspberry also contains an LTP-homologous protein, and LTPs have also been identified in grape, chestnut, hazelnut, maize, barley, asparagus, carrot and lettuce.

Blueberry Allergy Test: Clinical Experience

No studies have been reported on inducement of food allergy symptoms caused by blueberry as yet. However, anecdotal evidence suggests this is possible in food-sensitised individuals. The lack of data may be due to the low amounts generally consumed, or the low allergenicity of the fruit. With increased demand for blueberries as a foodstuff it is possible that further cases may come to light in future.