Beetroot

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Code: f319
Latin name: Beta vulgaris craca
Source material: Fresh root
Family: Chenopodiaceae
Common names: Beetroot, Beets, Garden beets, Table beets
There is confusion among Beetroot, Sugar beet and Spinach beet in many instances in the literature. We have taken note and distinguished these as Beetroot (f319), Sugar beet (w210) and Spinach beet.
 

Allergen Exposure

Geographical distribution
The ancestor of cultivated Beetroot grows wild on the seashores of southern Britain, through Europe and Asia, as far as the East Indies. Beets and their relatives are grown throughout the world for human and stock food. Sugar beets and Chard are among the more familiar types.

Beets are grown primarily for the enlarged bulbous root, which forms near or just above the soil surface. The plant is naturally a biennial, producing a rosette of leaves and a bulbous root one year, and a seed stalk the following year. Except for seed production, however, the plant is grown from seed as an annual. It is usually harvested when the near-globular or oblate enlarged root is not more than 6 cm in diameter. Colours range from the familiar bright red (“beetroot”) to white to striped. The Beet develops best under cool conditions, and so may be grown in winter in the far south, or in summer in the north.

Environment
Beets grow only in cultivated beds. Beetroot is available fresh or canned, and can be eaten raw or cooked. It is traditionally boiled until tender, then pickled in vinegar and used in salads, but it can also be baked, steamed, or microwaved. The leaves can be eaten raw or cooked like Spinach. Wine has been made from Beetroot. Beetroot has one of highest sugar contents among vegetables. It is an excellent source of vitamins and minerals.

Beetroot contains betacyanin pigment (betaine), which is commercially extracted to make the colourant Beetroot red. The root of this and other red-rooted forms contains betanin, an anthocyanin similar to those found in red wine, which is partly responsible for red Beets’ immune-enhancing effect. This is one reason for use of the root as an herbal remedy.

Allergens
No allergens from this plant have yet been characterised.

A gene has been isolated from a Beta vulgaris, which encodes for a protein that resembles members of the Latex allergen Hev b 5 family (1). A gene encoding for a chitinase with a hevein-like domain was isolated from the leaves of the close family member Sugar beet. The gene is activated by fungal infection. Whether these proteins are clinically significant, or also present in the close family relative Beetroot, has not yet been determined (2).

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 Chenopodiaceae (3).

Clinical Experience

IgE-mediated reactions
Anecdotal evidence suggests that Beetroot can occasionally induce symptoms of food allergy in sensitised individuals; however, no studies have been reported to date.

Other reactions
Beetroot is known to produce red urine in some people following its ingestion, whereas others appear to be able to eat the vegetable with impunity (4-5). Beeturia is the excretion of red Beetroot pigment (betalaine) in urine and faeces. It occurs in about 14% of humans.

Betalaine is a redox indicator whose colour is protected by reducing agents. Thus, beeturia results from colonic absorption of betalaine: oxalic acid preserves the red colour through to the colon; otherwise, in non-beeturic individuals, betalaine is decolourised by non-enzymatic processes in the stomach and colon (6).

Beetroot has one of the highest nitrate contents found in vegetables (7).

Beetroot is also high in oxalate (8).

Compiled by Dr Harris Steinman, harris@zingsolutions.com

References

  1. Fowler MR, Gartland J, Norton W, Slater A, Elliott MC, Scott NW. RS2: a sugar beet gene related to the latex allergen Hev b 5 family.
    J Exp Bot 2000;51(353):2125-6
  2. Berglund L, Brunstedt J, Nielsen KK, Chen Z, Mikkelsen JD, Marcker KA. A proline-rich chitinase from Beta vulgaris.
    Plant Mol Biol 1995;27(1):211-6
  3. Yman L. Botanical relations and immuno-logical cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09
  4. Mitchell SC. Food idiosyncrasies: beetroot and asparagus.
    Drug Metab Dispos 2001;29(4 Pt 2):539-43
  5. Pearcy RM, Mitchell SC, Smith RL. Beetroot and red urine.
    Biochem Soc Trans 1992;20(1):22S
  6. Eastwood MA, Nyhlin H. Beeturia and colonic oxalic acid. QJM 1995;88(10):711-7
  7. Petersen A, Stoltze S. Nitrate and nitrite in vegetables on the Danish market: content and intake.
    Food Addit Contam 1999;16(7):291-9
  8. Finch AM, Kasidas GP, Rose GA. Urine composition in normal subjects after oral ingestion of oxalate-rich foods.
    Clin Sci (Lond) 1981;60(4):411-8

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.