Brussels sprouts are a food which may result in allergy symptoms in sensitised individuals.

Brussels Sprouts Allergy Test: Allergen Exposure

The Brussels sprout originated in the Mediterranean region from a loose-leafed wild plant which was domesticated and eventually bred into a number of varying forms of the same species which are cultivated today, including the cabbage, broccoli, brussels sprout, kale and kohlrabi.

The plant’s name originates in the Belgian capital city of the same name, as it is said to have been cultivated here around the 1300s. Now, it is produced in a wide range of countries across Western and Central Europe, Japan, and North America. The majority of production is for the frozen food market, with the remainder being canned or sold fresh.

If kept frozen or at near-freezing temperatures, Brussels sprouts can be expected to last for around a month before beginning to discolor or wilt, or for around two weeks at refrigerator temperatures.

The plant is a cool-season biennial, ranging in colour from light green to deep grayish-green, and with round to heart-shaped leaves. The sprouts themselves are modified leaves forming “heads.” Many rows of sprouts grow on a single long stalk, ranging in diameter from 1 to 4 cm.

Brussels sprouts are available canned, frozen or fresh, and are most often boiled or steamed and served as a side dish. They are high in vitamins A, C and K, and are a fairly good source of iron, as well as containing more moderate amounts of B vitamins, such as folate and vitamin B6.

Brussels sprouts, as with broccoli and other brassicas, contain sulforaphane, a phytochemical under basic research for its potential biological properties. Although boiling reduces the level of sulforaphane, neither steaming, microwave cooking, nor stir frying cause a significant loss.

Brussels Sprouts Allergy Test: Allergen Description

No allergens from this plant have yet been characterised.

A lipid transfer protein (LTP) has been isolated from a close family member, broccoli, suggesting that Brussels sprouts may contain a LTP. This has not been demonstrated to date.

The lack of allergens makes the Brussels sprout a useful replacement food for many patients with multiple food allergy.

Brussels Sprouts Allergy Test: Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, as well as to a certain degree among members of the family Brassicaceae, such as broccoli, cauliflower, brussels sprouts, and cabbage.

This has been supported by a study that reported cross-reactivity among cabbage, broccoli, cauliflower, brussels sprouts, mustard, rape and turnip.

Cross reactivity among other plants containing LTP is also possible.

Brussels Sprouts Allergy Test: Clinical Experience

Anecdotal evidence suggests that Brussels sprouts can occasionally induce symptoms of food allergy in sensitised individuals; however, no studies have been reported to date.

Other reactions

Consuming Brussels sprouts in excess may not be suitable for people taking anticoagulants, such as warfarin, since they contain vitamin K, a blood-clotting factor. In one incident, eating too many Brussels sprouts led to hospitalization for an individual on blood-thinning therapy.