White bean (the beans actually range in colour from pale green to creamy white) is a term given to varieties of beans that have light-coloured seeds. They are less robust in flavour than the Green bean and Red kidney bean, but in some countries they are a staple food. There are several varieties of White beans, each tending to be used in different dishes. For example, White beans may be used as "Haricot beans" in stews, or as canned baked beans.

White beans are traditionally eaten alone, without the pods. They are usually available only canned, dried or (occasionally) frozen. They are baked with sauces, or added to soups, stews and baked dishes. The seed may be sprouted and used in salads or cooked. White beans are an excellent source of iron and folate and a good source of magnesium, phosphorus, potassium, and copper.

The green or dried mature pods, or the seeds alone, are reported to have diuretic, hypoglycaemic and hypotensive actions. The seeds or the whole plant may be used as a homeopathic remedy for a variety of diseases. Ground into flour, the seeds are used externally in the treatment of ulcers.

IgE-mediated reactions

White bean may uncommonly induce symptoms of food allergy in sensitised individuals.

A study reports on a 33-year-old woman who developed tongue swelling and burning and mouth itching minutes after eating baked Beans. Similar symptoms occurred a day after ingesting Pea soup, on another occasion within 15 minutes of eating a Bean burrito, and again 20 minutes after eating chilli containing Kidney and Pinto beans. In this last instance, she also developed chest tightness, wheezing, generalised erythema, urticaria, abdominal pain, a feeling of impending doom and light-headedness. SPT was positive to Red kidney and White bean, but negative to Pea, Green and Lima bean. IgE antibodies were found to Red kidney, Pinto and White bean, and to Chick pea, Pea and Black-eyed pea (1).

A 7-year-old boy was described who developed angioedema associated with inhalation of vapours from cooked White bean. SPT evaluation using the prick-to-prick method was positive for White bean. IgE antibody determination was positive for White bean and Green bean. The patient also developed angioedema after ingesting cooked White bean (2).

Other reactions

The root is dangerously narcotic. Large quantities of the raw mature seed may be poisonous. Flatulence is also a hazard.

No allergens from this plant have yet been characterised.

An alpha-amylase inhibitor has been isolated (3). The allergenicity of this protein has not been determined yet.

Phaseolus vulgaris contains a chitinase of unknown allergenicity (4).

Cross Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected but in fact is not seen frequently (5).

Legumes have structurally homologous proteins, but they are not all equally allergenic, making it difficult to distinguish in vitro and in vivo cross-reactivity. In SPT serum IgE antibody tests, most patients are shown to be sensitised to more than 1 species, but this may be clinically irrelevant. For example, in an in vitro study, the specific IgE binding by protein extracts of 11 food legumes was examined by IgE antibody determination and RAST inhibition. Cross-allergenicity was demonstrated to be most marked between the extracts of Peanut, Garden pea, Chick pea, and Soybean (6-7), and between Pea and Soybean (8). However, clinical studies have found that there is little cross-reactivity between members of the legume family (9-11).

In a recent Spanish study, a high degree of cross-reactivity was demonstrated by inhibition studies among Lentil, Chick pea, Pea and Peanut. The majority of the study group had had symptoms with more than 1 legume (median 3 legumes). Thirty-nine patients were challenged (open or simple blind) with 2 or more legumes and 32 (82%) reacted to 2 or more legumes: 43.5% to 3, 25.6% to 2, 13% to 4 legumes. Seventy-three per cent of the patients challenged with Lentil and Pea had positive challenges to both, 69.4% to Lentil and Chick pea, 60% to Chick pea, and 64.3% to Lentil, Chick pea and Pea simultaneously. However, White bean, Green bean and Soy were generally well tolerated by children allergic to other legumes. The authors argued that, unlike in the Anglo-Saxon population, this phenomenon implies clinical sensitisation for many Spanish children (12).

The Peanut vicilin storage protein shares significant sequence homology with the vicilin storage proteins of other legumes, e.g., Soybean, Pea, and Common bean (13). This does not necessarily indicate clinical cross-reactivity but would explain why IgE antibodies to other legumes may be found in serum.

A study investigated the in vitro cross-reactivity of allergens from Mesquite tree pollen (Honey locust tree; Prosopis juliflora) and Lima bean (Phaseolus limensis/Phaseolus lunatus). Of 110 patients with asthma, rhinitis or both, as evaluated by intradermal test, 20 were highly positive to Mesquite pollen extract. Of these, 12 patients showed elevated IgE antibody level to Mesquite pollen extract alone, and 4 to both Lima bean and pollen extract. Lima bean extract could inhibit IgE binding to Mesquite in a dose-dependent manner. Also, humoral and cellular cross-reactivity was demonstrated (14). Although cross-reactivity was not investigated between Mesquite and White bean per se, cross-reactivity may exist between pollen from this tree and other species of Phaseolus.

Last reviewed : June 2022