Asparagus belongs to a family that contains ferns and vegetables and consists of 125 species in the genus. This well-known table delicacy has been cultivated for more than 2,000 years and was much esteemed from the time of the Greeks and Romans. It is an important commercial and garden crop in many parts of the world. Its relatively high price tends to make it a luxury in some parts of the world.

Asparagus is native to marshes of southwest Europe and may be found wild on the seacoast in southwest England. In the southern parts of Russia and Poland the waste steppes are covered with this plant. It is also common as a wild plant in Greece. Otherwise, it is found in cultivated beds.

Asparagus plants, a cultivated form of the lily family, are perennials with edible aerial stems (spears) growing upward. The tender, succulent spears are cut in the spring for 2 or 3 months. Asparagus has both male and female plants. There are two main varieties of Asparagus, the tougher green one, and the more tender white one, which is preferred in Europe and grown in shade or underground, to keep it from producing chlorophyll.

Asparagus is available fresh, canned or frozen and is often served as a side dish, after being steamed or briefly boiled. The tough base of the stem is usually removed before cooking, and sometimes the plant is peeled then as well.

The smell in one’s urine after eating Asparagus is caused by excretion of the substance methyl mercaptan. Asparagus is well known as a diuretic and laxative; and has been used to treat gravel and dropsy. It has been a folk remedy for eye ailments, toothache, cramps, convulsions, and sciatica.

Asparagus contains sucrose, mucilage, asparagin (asparagine), coniferin and the glucoside vanillin. (Rademaker 2000 ref. 6751 4)

Asparagus also contains folates, Vit C, as well as smaller amounts of Vit A and beta carotene. Fructose-containing oligosaccharides, which occur naturally in a variety of plants such as onion, asparagus, chicory, banana and artichoke, are very good prebiotics. (Gibson 1998 ref.6752 3)

Asparagus is high in purines.

Said to be effective against nausea and heartburn.

Allergens/Function:

Allergens:
Aspa o 1

A Bet v 1 homologue is present. (Carpin 1997 ref.6754 1)

At least six IgE-binding components, ranging from 22 to 73 kDa, have been detected in raw asparagus (and not cooked) and shown to be very labile and quite sensitive to heat denaturation. (Lopez-Rubio 1998 ref.3065 8)

Two LTPs (lipid transfer proteins) have been isolated from asparagus, and demonstrated an amino acid sequence similar to that of Pru p 3 from peach and a strong reaction to anti-Pru p 3 antibodies. Each isolated protein reached inhibition values of up to 60% in CAP inhibition assays against asparagus extracts and elicited positive SPT responses in 9 of 18 patients with asparagus allergy. A profilin and cross-reacting carbohydrate determinants as asparagus IgE-binding components were also detected. The authors conclude that asparagus LTPs are relevant allergens. In addition, profilin and glycoproteins harboring complex asparagine-linked glycans can also be involved in asparagus allergy. (Diaz-Perales 2002 ref.7045 6)

The allergen may be a plant growth inhibitor, 1,2,3-Trithiane-5-carboxylic acid, which is present in young shoots. (Rademaker 2000 ref. 6751 4)

1,2,3-Trithiane-5-carboxylic acid, a sulfur-containing growth inhibitor, was shown to be a first contact allergen from asparagus, occurring in asparagus and occurs mainly in the early phase of the growing season. (Hausen 1996 ref.2213 8)

A 28 kDa protein, cysteine protease has been isolated from young stems of asparagus. Its allergenicity is not known as yet. 8 of 12 N-terminal sequence residues are similar to that of papain. (Yonezawa 1998 ref.6753 1)

Used in Chinese medicine as a tonic, hormonal tonic in India. Tonic for lungs in consumptive diseases and for AIDS wasting.

Adverse Reactions:

IGE AND IMMUNE:
Asparagus is not a frequent cause of allergy reactions.

Asthma, anaphylaxis, and/or contact urticaria. (Diaz-Perales 2002 ref.7045 4)

Conjunctivitis, rhinitis, tightness of the throat and coughing during preparation of fresh asparagus is reported in two individuals. No symptoms occurred while eating the cooked food. The authors suggest that the allergen was inhaled. (Eng 1996 ref.698 34)

Allergic contact dermatitis. (Hausen 1996 ref.2213 8)

Acute urticaria after ingestion of asparagus. (Escribano 1998 ref.2339 1)

Contact urticaria caused by asparagus. (Sanchez 1997 ref.2340 6)

This study reports on two patients with IgE-mediated contact urticaria to canned asparagus. (Sanchez-Hernandez 2000 ref.6812 5)

Crossreactivity. Occasionally cross-reacts with onions and garlic as they are all members of the same botanical family.

OCCUPATIONAL EXPOSURE:
Farming, food industry

A 53-year-old farm worker presented with a 3-year history of an occupational allergic contact dermatitis to asparagus. (Rademaker 2000 ref. 6751 4)

Occupational contact dermatitis, contact urticaria, rhinoconjunctivitis and asthma. (Tabar 1994 ref.2195 8) Occupational asthma. (Reguera 1994 ref.2196 8)

Occupational asthma and rhinoconjuctivitis within 10 minutes in a 28 year old man due to inhalation of asparagus allergens during cutting of the spears while harvesting asparagus. (Lopez-Rubio 1998 ref.3065 8)

NON IMMUNE:
Asparagus is associated with the production of a malodorous urine smelling like rotten cabbage. This occurs in approximately 43% of people and has been shown to remain with individuals for virtually a lifetime. Family studies suggest that the ability to produce the odorous urine is inherited as an autosomal dominant trait. Those who produce this odor assume that everyone does, and those who do not produce it have no idea of its potential olfactory consequences. (Mitchell 2001 ref.6625 6) (Mitchell 1987 ref.6646 0)