Broccoli, a cultivar of wild cabbage, is a plant of the Cabbage family, Brassicaceae (formerly Cruciferae). Wild cabbage/wild mustard originated along the northern and western coasts of the Mediterranean. This plant was domesticated and eventually bred into widely varying forms, including Broccoli, Cauliflower, Cabbage, kale, kohlrabi, and Brussels sprouts, all of which remain the same species (1).
Broccoli is considered to be a further development of Cauliflower. It has been known only since the 18th century. It prefers areas with mild winters such as Italy, France, England, California, the southern American States, and sub-tropical Africa.
In contrast to Cauliflower, the flower head develops to a certain extent before harvesting. The edible parts of the Broccoli plant are the stout, tender stem and unopened flower buds. Broccoli must be cut as soon as it reaches full bud development, before buds swell and open into flowers. Varieties exist with white, yellow, purple and deep emerald-green heads. There are 3 main types of Broccoli. The typical green or purple Broccoli with a large, central head is a “Calabrese”.
“Romanesco” Broccolis have flower buds grouped in numerous small cone-shaped heads, arranged in spirals; the “Sprouting Broccolis” produce a succession of small flowering heads over an extended season.
Broccoli is found in cultivated beds. The stems and florets can be steamed or boiled and served as a side dish, or served raw on a crudité platter, or stir-fried.
Broccoli is an excellent source of vitamins A and C, as well as riboflavin, calcium and iron, and is a rich source of vitamin K. However, Broccoli reduces iodine absorption. Broccoli and other members of the genus Brassica (Cabbage-like vegetables) contain very high levels of antioxidant and anticancer compounds. Vitamins and nutrients typically are more concentrated in the flower buds than in the leaves, and that makes Broccoli a better source of vitamins and nutrients than Brassica crops in which only the leaves are eaten. Some research has suggested that the compounds in Broccoli and other Brassicas can protect the eyes against macular degeneration, the leading cause of blindness in older people.
No allergens have been characterised to date.
A 9 kDa protein, a lipid transfer protein (LTP), has been detected or inferred (2-5). LTP’s are heat-stable allergens.
A 9 kDa lipid transfer protein has been isolated from the surface wax of Broccoli leaves. The amino acid sequence showed 40 to 50% identity with nonspecific lipid transfer proteins isolated from various other plants. Antigenicity was not determined in this study (6).
A study has demonstrated that Oilseed rape and Turnip rape, closely related family members, contain 2S albumins (7). Broccoli was not evaluated for this potential allergen.
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 (8). This has been bourne out by a study that reported cross-reactivity among Cabbage, Broccoli, Cauliflower, Mustard, Rape and Turnip (9). Some authors disagree and state that cross-reactivity among the Brassicaceae species is rare (10).
A lipid transfer protein (LTP) was isolated from Broccoli and found to be similar to the LTP purified from Peach peel and Carrot (1,3). Cross-reactivity among plants containing LTP is possible.
Anecdotal evidence suggests that Broccoli can occasionally induce symptoms of food allergy in sensitised individuals; however, few studies have been reported to date.
A positive reaction to Broccoli in a skin test of a female patient has been reported (8). She experienced pain and swelling in the mouth and throat, plus breathing difficulties, after intake of coleslaw. The researchers concluded: “IgE sensitivity can occur to foods in the Brassica family not normally thought to cause allergic reactions in man. It is vital for the physician to consider these foods when evaluating patients for food allergy”.
Allergic and occupational contact dermatitis to Broccoli has been reported (11-12). A 56-year-old female nurse presented with a 3-year history of severe eczema and recurrent blisters of her palms, with the left being more severely affected than the right. She was patch tested with, among other substances, parts of fresh vegetables that she commonly used (Carrot, Parsnip, Potato, Broccoli, Onion, Tomato and Bean (unspecified)). There was a positive reaction to cobalt, Compositae mix and Broccoli at 48 and 96 hours. A usage test with Latex gloves, a skin prick test to commercial Latex solution, and a skin prick test to Broccoli were negative. The patient’s hand eczema improved remarkably on avoiding direct contact with Broccoli and other vegetables (11).
Maternal intake of Cabbage, Cauliflower, Broccoli, Cow’s milk, Onion, and Chocolate were significantly related to colic symptoms in exclusively breast-fed infants (13).
Compiled by Dr Harris Steinman, firstname.lastname@example.org
Wikipedia contributors, ”Broccoli,” Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Broccoli&oldid=236472388 (accessed September 8, 2008)
International Union of Immunological Societies Allergen Nomenclature: IUIS official list http://www.allergen.org/List.htm 2008
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J Allergy Clin Immunol 2006;117(6):1423-9
Pyee J, Yu H, Kolattukudy PE. Identification of a lipid transfer protein as the major protein in the surface wax of broccoli (Brassica oleracea) leaves.
Arch Biochem Biophys 1994;311(2):460-8
Puumalainen TJ, Poikonen S, Kotovuori A, Vaali K, Kalkkinen N, Reunala T, Turjanmaa K,
Palosuo T. Napins, 2S albumins, are major allergens in oilseed rape and turnip rape.
J Allergy Clin Immunol 2006;117(2):426-32
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Chakrabarti A, Prais L, Foulds IS. Allergic contact dermatitis to broccoli.
Br J Dermatol 2003;148(1):172-3
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Lust KD, Brown JE, et al. Maternal intake of cruciferous vegetables and other foods and colic symptoms in exclusively breast-fed infants. J Am Diet Assoc 1996;96(1):46-8