f234 Vanilla

Vanilla is native to Mexico, where it is still grown commercially. Vanilla was used by the Aztecs for flavouring the drink xocolatl, a mixture of cocoa beans, Vanilla and honey. The explorer Cortes brought Vanilla to Europe in the sixteenth century.

Vanilla is a tropical climbing orchid, with a long, green, fleshy stem that sprouts roots that cling to trees parasitically, reaching a height of up to 5 m. Its dull yellow or orange orchidaceous flowers grow in bunches, opening one by one each day during the 2-month season. The spice Vanilla is the fermented and cured fruit or pod of the orchid, about 12 to 24 cm long and usually referred to as Vanilla beans. In nature they are pollinated only by Mexican bees and hummingbirds that can penetrate the tough membrane that separates the plant’s pistol and stamen, so that in its non-native environment—Madagascar, Indonesia and so on - Vanilla plants are not fertile unless they are artificially pollinated. This and a complex and labour-intensive curing process - at the end of which the aroma substance vanillin, in the form of fine white crystals, is deposited on the fruit - explain why, next to Saffron and Cardamom, Vanilla is the world’s most expensive spice.

Once the beans are cured, they can be used in their whole or ground form, but they are most often used in the production of powders, flavours, oleoresins and extracts, particularly vanillin, which is present in Balsam of Peru and acts as an antioxidant to protect unsaturated fatty acids in commercial products such as baked goods. It can also be employed as a chemical reagent. Vanilla extract is made by soaking the chopped bean in an alcohol-water solution. Europeans prefer to use the bean, while North Americans usually use the extract.

Vanilla "flavour" as opposed to Vanilla extract, may be a blend of artificial and natural substances, or might not contain any Vanilla at all. Vanillin can be produced artificially from eugenol or iso-eugenol, as a by-product of coal tar or wood pulp, among other materials. Along with ethylvanillin (ethylprotocatechol aldehyde) and methylvanillin (methyl-protocatechol aldehyde), synthetic vanillin is replacing natural Vanilla, which is much more expensive. However, the flavour of these is not considered equivalent to that of natural Vanilla and is not esteemed by food experts.

Worse, Vanilla extract may be adulterated by coumarin flavoring. Latin American “Vanilla” may contain or consist entirely of Tonka bean, which is poisonous and carcinogenic. Vanilla “flavour” may also contain a number of synthetic chemicals less innocuous than vanillin.

Vanilla’s mellow flavour enhances a variety of sweet dishes: puddings, cakes, custards, creams, soufflés and ice cream. Vanilla flavours many commercial chocolate and confectionery items and several liqueurs such as Crème de Cacao and Galliano. It occurs in perfumes, cigars, cosmetics and pharmaceuticals.

From the time of the Aztecs, Vanilla was considered an aphrodisiac. It was also once believed to be a febrifuge. Now, it is rarely used for any medicinal purposes other than as a pharmaceutical flavouring. But vanillin is of interest because of its biogenetic relationship to the phenylpropanoid pathway and to other molecules of physiological significance, notably salicylate (1).

Allergen description

No allergens from this plant have yet been characterised.

Potential Cross Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected but in fact does not occur frequently (2).

Clinical Experience

IgE-mediated reactions

Vanilla may uncommonly induce symptoms of food or skin allergy in sensitised individuals (3). Reactions are most likely delayed or Type IV.

Other reactions

Contact sensitivity to Vanilla was experienced in a lip salve, in a 13-year-old girl who had a 2-year history of recurrent dermatitis on and around her lips (4).

Allergy to Vanilla on a face as a result of a hair lotion containing tincture of Vanilla has been described (5).

The role of flavouring was studied in 11 children under 5 years of age suffering from severe atopic dermatitis. In all cases, the dietary questionnaire showed a high daily intake of natural Vanilla and artificial vanillin. Double-blind oral provocation tests were carried out with Balsam of Peru (225 mg), natural Vanilla (50 mg), and artificial vanillin (12.5 mg). Nine children out of 11 presented eczematous reactions, and 1 presented urticaria. Elimination of food flavouring agents resulted in a clear improvement in 6 children. The authors point out the risk of increasing consumption of flavouring agents, and bring into question the traditional attitude of considering food flavouring agents as innocuous (6).

Although vanillin accounts for only 1.30 % of the content of Balsam of Peru (BP), it causes delayed hypersensitivity in 2.6 % of those patients who are allergic to BP (7). Its ingestion also causes reactions in subjects who are allergic to BP (8-10).

Bronchospasm caused by vanillin and lactose was detected in controlled double-blind challenge tests in an asthmatic patient (11, 12).

Occupational contact dermatitis from Vanilla may occur from growing or processing Vanilla, in the manufacture of vanillin, or in bakers and beverage makers (13-15). Occupational dermatitis may occur as a result of the Vanilla itself or the volatile oil present.

Ethylvanillin has been found to be the cause of a case of occupational contact dermatitis (16).

Last reviewed: June 2022.