Fenugreek
Route Of Exposure
Native to western Asia and south-eastern Europe, this aromatic legume plant is well-known almost worldwide for its pleasantly bitter, slightly sweet seeds, sometimes described as having a suggestion of burnt sugar. Fenugreek grows in many parts of the world today, including India, northern Africa and the United States. The seed, dried for use, is about 3mm long, about 10 to 20 seeds being produced in each long pod. Its leaves are less widely used. The seeds are made up of mucilaginous fibre (± 50% by weight) and steroid saponins (± 50% by weight).
Fenugreek may grow wild, but for commercial purposes is generally cultivated. The very aromatic leaves (not generally available in the United States) can be used in salads, as a potherb or as a flavouring, especially in curries. Pods may be cooked whole. Fenugreek seeds, which come whole and ground, are used to flavour many foods, including curry powders, spice blends and teas. The sprouted seeds may be added to salads or cooked. An essential oil obtained from the seed is used as food flavouring in imitation maple syrup, vanilla compositions, liquorice, pickles, etc. The roasted seed is a coffee substitute.
Fenugreek has many uses as an herbal medicine (both topical and ingested); especially in North Africa, the Middle East and India. Western pharmacological uses have borne out reports of the plant’s efficacy. For example, Fenugreek and isolated Fenugreek fractions have been shown to act as hypoglycaemic and hypocholesterolaemic agents in both animal and human studies. Fenugreek is purported to be effective in initiating and maintaining adequate milk production. Research has also shown that the seeds can inhibit cancer, lower blood cholesterol levels and have an antidiabetic effect. The seeds are very nourishing and are given to convalescents and to encourage weight gain, especially in cases of anorexia nervosa. The seeds should not be prescribed medicinally for pregnant women, since they can induce uterine contractions.
The plant is employed as a green manure crop, for cosmetic purposes, and as a dye ingredient.
Clinical Relevance
Allergen Description
Allergens from 20 kDa to 70 kDa have been detected. In an early study of two Fenugreek-allergic individuals, the serum of patient 1 showed a binding of specific IgE with the 70, 68, 60, 55, 52, 48, 40, 34, 30, 29, 24, and 22 kDa, and the serum of patient 2 showed specific IgE binding with 70, 60, 52, 48, 45, 40, and 30 kDa bands. Fenugreek allergens of 50, 52, and 74 kDa have been identified as major allergens. In a study of sera of peanut-allergic patients, IgE bound to 18 proteins in fenugreek seed extract, with 7 proteins being identified more frequently. The most dominant protein bands were at 49.4 kDa, 56.5 kDa, and 66.0 kDa.
The following allergens have been characterised:
Potential Cross Reactivity
Extensive cross-reactivity between the different individual species of the genus could be expected, but in fact is not seen frequently. In an in-vitro study, the specific IgE binding by protein extracts of 11 food legumes was examined by RAST and RAST inhibition. Cross-allergenicity was demonstrated to be most marked between the extracts of peanut, garden pea, chick pea, and soybean. However, clinical studies have found that there is little cross-reactivity between members of the legume family.
Fenugreek 7S-vicilin (Tri fg 1) and 11S-legumin (Tri fg 3) have been partly sequenced, and were shown to have considerable homologies to peanut Ara h 1 and Ara h 3, respectively.
Clinical Experience
IgE-mediated reactions
Anecdotal evidence suggests that fenugreek may induce symptoms of food allergy in sensitised individuals; however, few studies have been reported to date. It is possible that the allergy occurs more frequently than has been reported.
Reactions may follow ingestion, inhalation or external application of fenugreek seed powder. Two cases of immediate severe allergy to fenugreek have been described. In the first case, inhalation of the fenugreek seed powder resulted in rhinorrhea, wheezing and fainting. The second case was of a patient with chronic asthma who developed numbness of the head, facial angioedema, and wheezing after application of fenugreek paste to her scalp as a treatment for dandruff. Skin reactivity was detected to fenugreek and chickpeas. During double-blind, placebo-controlled food challenge, both patients showed a > 20% drop in peak flow rate after consumption of fenugreek and chickpea.
Anaphylaxis to curry powder was described in a 26-year-old nurse who presented with bronchospasm. Her initial symptoms were generalised itching, diarrhoea and stridor which were reproduced 20 minutes later following an oral challenge of curry and rice. The causative allergens were narrowed down to cardamom and fenugreek. Serum IgE antibodies to both were high.
An Algerian student using fenugreek powder orally as an appetite stimulant and topically as a healing agent was reported to have rhinitis and asthma as a result of handling the powder. A prick test with fenugreek powder was strongly positive.
Fenugreek has also been reported to result in occupational asthma.
This study describes a patient, working in a spice factory, with anaphylaxis from coriander in a meal. He also demonstrated urticaria, angioedema, rhinoconjunctivitis and bronchospasm during handling coriander and fenugreek. SPT, serum IgE antibodies and basophil activation tests were clearly positive in the patient. No cross-reactivity between fenugreek and coriander was demonstrable by inhibition experiments.
Other reactions
The seed contains 1% saponins. Although poisonous, saponins are poorly absorbed by the human body, and so most pass through without harm. Only large amounts tend to be dangerous. Leaching or thorough cooking will remove most saponins.
Non-steroidal anti-inflammatory drugs, particularly aspirin, have the potential to interact with herbal supplements containing coumarin (e.g. fenugreek), resulting in bleeding or potentiation of the effects of warfarin therapy.
Fenugreek, maple syrup, and the urine of maple syrup urine disease patients all share a characteristic odour (‘maple syrup’ urine odour), originating from a common component, sotolone. Maple syrup urine disease is an autosomal recessive inherited disorder of amino acid metabolism. The disease gives a characteristic sweet aroma, reminiscent of maple syrup, to the body fluids (e.g. urine) of affected patients. The substance responsible for the odour is 4,5-dimethyl-3-hydroxy-2[5H]-furanone (sotolone), a compound also present in fenugreek and lovage. Ingestion of fenugreek by mothers during labour resulted in a maple syrup-like odour in their newborn infants, leading to a false suspicion of maple syrup urine disease.
References
- Mohan V, Balasubramanyam M. Fenugreek and Insulin Resistance. [Editorial] JAPI 2001;49:1055-6.
- Patil SP, Niphadkar PV, Bapat MM. Allergy to fenugreek (Trigonella foenum graecum). Ann Allergy Asthma Immunol 1997;78(3):297-300.
- Madar Z, Stark AH. New legume sources as therapeutic agents. Br J Nutr 2002;88 Suppl 3:287-92.
- Gabay MP. Galactogogues: medications that induce lactation. J Hum Lact 2002;18(3):274-9.
- Faeste CK, Christians U, Egaas E, Jonscher KR. Characterization of potential allergens in fenugreek (Trigonella foenum-graecum) using patient sera and MS-based proteomic analysis. J Proteomics 2010;73(7):1321-33.
- Kruse Fæste C, Namork E, Lindvik H. Allergenicity and antigenicity of fenugreek (Trigonella foenum-graecum) proteins in foods. J Allergy Clin Immunol 2009;123(1):187-94.
- Faeste CK, Namork E. Fenugreek proteins are potential food allergens. (Poster) 2nd Int Symp Molecular Allergol, Rome, Italy;22-24 April 2007.
- Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09.
- Barnett D, Bonham B, Howden ME. Allergenic cross-reactions among legume foods--an in vitro study. J Allergy Clin Immunol 1987;79(3):433-8.
- Bernhisel-Broadbent J, Sampson HA. Cross-allergenicity in the legume botanical family in children with food hypersensitivity. J Allergy Clin Immunol 1989;83:435-40.
- Yagami A, Nakazawa Y, Suzuki K, Matsunaga K. Curry spice allergy associated with pollen-food allergy syndrome and latex fruit-syndrome. J Dermatol 2009;36(1):45-9.
- Ohnuma N, Yamaguchi E, Kawakami Y. Anaphylaxis to curry powder. Allergy 1998;53(4):452-4.
- Bessot JC, Gourdon C, Pauli G. Respiratory allergy to Fenugreek. Rev Fr Allergol Immunol Clin 1996;36(5):510-2.
- Dugue P, Bel J, Figueredo M. Fenugreek causing a new type of occupational asthma. [Letter] [French] Presse Med 1993;22(19):922.
- Ebo DG, Bridts CH, Mertens MH, Stevens WJ. Coriander anaphylaxis in a spice grinder with undetected occupational allergy. Acta Clin Belg 2006;61(3):152-6.
- Abebe W. Herbal medication: potential for adverse interactions with analgesic drugs. J Clin Pharm Ther 2002;27(6):391-401.
- Heck AM, DeWitt BA, Lukes AL. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm 2000;57(13):1221-7.
- Lambert JP, Cormier J. Potential interaction between warfarin and boldo-fenugreek. Pharmacotherapy 2001;21(4):509-12.
- Korman SH, Cohen E, Preminger A. Pseudo-maple syrup urine disease due to maternal prenatal ingestion of fenugreek. J Paediatr Child Health 2001;37(4):403-4.
- Bartley GB, Hilty MD, Andreson BD, Clairmont AC, Maschke SP. "Maple-syrup" urine odor due to fenugreek ingestion. N Engl J Med 1981;305(8):467.
- Yalcin SS, Tekinalp G, Ozalp I. Peculiar odor of traditional food and maple syrup urine disease. Pediatr Int 1999;41(1):108-9.
- Monastiri K, Limame K, Kaabachi N, Kharrat H, Bousnina S, Pousse H, Radhouane M, Gueddiche MN, Snoussi N. Fenugreek odour in maple syrup urine disease. J Inherit Metab Dis 1997;20(4):614-5.
- Podebrad F, Heil M, Reichert S, Mosandl A, Sewell AC, Bohles H. 4,5-dimethyl-3-hydroxy-2[5H]-furanone (sotolone)--the odour of maple syrup urine disease. J Inherit Metab Dis 1999;22(2):107-14.