Garlic is a small, very pungent onion-like plant. Garlic has been used for millennia, having been mentioned 1550 BC, as flavoring and a medicine, and is now important in most cuisines worldwide. In some parts of the world, their use also has religious connotations.

Allium is a genus of some 500 species belonging to the family Liliaceae. However, only a few of these are important as food plants, notably Onion, Garlic, Chive, Leek, and Rakkyo. Garlic is a cousin to Leeks, Chives, Onions and Shallots. The edible bulb or "head" grows beneath the ground. This bulb is made up of sections called cloves, each encased in its own parchment-like membrane. Today's major Garlic suppliers include the United States (mainly California, Texas and Louisiana), France, Spain, Italy and Mexico. There are several major types of Garlic available, with cloves up to 6cm in diameter. The flavors of different members of Alliums, in addition to being characteristic, are complex, being derived enzymatically from a number of involatile precursors. Fresh Garlic is available year-round.

Garlic grows in cultivated beds, with occasional escapes. Garlic bulbs are eaten as flavoring either raw or cooked. They are usually peeled before use in recipes. Crushing, chopping, pressing or pureeing Garlic releases more of its essential oils and provides a sharper, more assertive flavor than slicing or leaving it whole. Garlic is readily available in forms other than fresh, such as dehydrated flakes or powder. Garlic salt is Garlic powder blended with salt and a moisture-absorbing agent. Garlic extract and Garlic juice are derived from pressed Garlic cloves. One unfortunate side effect of Garlic is that, because its essential oils permeate the lung tissue, it remains with the body long after it has been consumed, affecting breath and even skin odor. The stems, leaves and flowering seed can be eaten raw or cooked, and are rather milder than the bulbs.

Such plants have been used for many centuries for their pungency and flavoring value, for their medicinal properties, and in some parts of the world, their use also has religious connotations. Garlic can reduce nasal congestion, and lower blood pressure and blood cholesterol. (For example, demographic studies suggest that Garlic is responsible for the low incidence of arteriosclerosis in areas of Italy and Spain where consumption of the bulb is heavy.) It has been employed as an antiviral, antibacterial, fungicidal, vermifuge, vasodilator, expectorant, diuretic, antiasthmatic, antispasmodic, febrifuge, stomachic, skin soothing, tonic, and immunostimulant agent. It may, however, induce migraines. Garlic extract inhibits chromosomal breaks due to sodium arsenite (arsenic), a contaminant in ground water. It has been shown that Garlic aids detoxification of chronic lead poisoning. It is also said to have anticancer activity. Recent research has indicated that Garlic reduces glucose metabolism in diabetics.

The growing plant is said to repel insects, rabbits and moles. An extract of the plant can be used as an insect repellent.

Cloves of Garlic are sometimes spread among stored fruit to delay the fruit from rotting. The juice is also used as glue in mending glass and china.

Both Oil and Extract are obtained from Garlic; Both are a yellow liquid with strong odour.

Allergens/Function:

Two major protein bands of 12 and 54 kDa have been isolated from garlic extract. (Anibarro 1997 ref.1837 3)

Protein bands of 10, 20 and 40 kDa were detected in a patient with urticaria affected by cooked and raw onions. Garlic appears to have heat-stabile and heat-labile allergens. (Asero 1998 ref.2211 0)

A 12 kDa protein band to young garlic, garlic, onion, and leek extracts was detected in a garlic-allergic individual. Similar bands could also be detected with mugwort pollen and hazelnut extract. (Perez-Pimiento 1999 ref.3838 9)

A 12 kDa and 40-50 kDa protein has been detected, (Pires 2002 ref.6809 2) probably corresponding to a mannose-binding lectin (Smeets 1997 ref.6814 2) and alliinase, both previously reported. (Rabinkov 1994 ref.6815 7) (Bartholomeus 2002 ref.6819 1)

Flavourant/Herb. Has also been used as an expectorant and disinfectant. Said to increase perspiration, aid urine flow, and have healing properties.

Garlic Extract and Oil, flavourant used for fruit and garlic flavourings. Also used to counteract intestinal worms.

Adverse Reactions:

IGE AND IMMUNE:
Allergic reactions - Asthma, nasal reactions. Diarrhoea. Flushing. Dermatitis.

Immediate allergic reactions to garlic ingestion or contact, is uncommon, especially in children. (Asero 1998 ref.2211 0) (Rance 1997 ref.1996 4)

Garlic is well known to cause contact dermatitis and asthma. However, it is a very rare cause of food allergy. This study reports on a 23 year old woman who experienced an anaphylactic reaction after eating young garlic. (Perez-Pimiento 1999 ref.3838 9)

A 16 month-old boy with history of cow's milk and white egg allergy, that developed urticaria on the face and neck immediately after contact with fresh garlic. He tolerated cooked garlic. (Pires 2002 ref.6809 2)

In the CICBAA data bank which includes 589 cases of food allergies, sensitization to Liliaceae: garlic, onion, chive, was observed in 4.6% of prick-tests in children, 7.7% of prick-tests in adults. (Moneret-Vautrin 2002 ref.5983 1)

One of the commonest causes of contact dermatitis of the hands. (Sinha 1977 ref.340 32) (Delaney 1996 ref.2209 3) Nausea. Wheezing. Diallyldisulfide is considered to be the major allergen of garlic oil and can induce irritation and vesication of the skin. Usually a superficial irritation of the skin, which can result in rubefacient and vesication.

The spectrum of garlic-related adverse reactions comprises irritant contact dermatitis, with the rare variant of zosteriform dermatitis; induction of pemphigus, allergic asthma and rhinitis; contact urticaria; protein contact dermatitis; allergic contact dermatitis, including the hematogenic variant; as well as combinations thereof. (Jappe 1999 ref.6830 1)

Crossreactive.

Garlic food allergy with symptoms of Meniere's disease?

Every drug that possesses an active thiol group in its molecule is capable of inducing pemphigus. Some plants, in particular those belonging to the Allium group, contain several active compounds with stable disulfide and thiol groups in their molecule, and could contribute to the induction of pemphigus. (Brenner 1994 ref.2373 3)

This study reports on a patient who presented with nasal symptoms when working with spices that included garlic and onion dust. Skin-prick tests were positive for onion, garlic powder and fresh Liliacea. Specific IgE were positive for garlic and onion. IgE immunoblotting showed very strong bands at 14 and 40 kD with garlic extract. Nasal challenge showed an increase in inspiratory nasal resistance which was higher than 100 % of the basal value for both onion extract and garlic. (Jimenez-Timon 2002 ref.7749 3)


OCCUPATIONAL EXPOSURE:
Food industry

Contact dermatitis due to garlic is usually due to handling of garlic for cooking. Among the Chinese, garlic is also used as a form of topical medicament. (Lee 1991 ref.6887 2)

Occupational asthma and rhinitis have been reported, which may have an onset long after working with the substance. (Seuri 1993 ref.636 21) (Lemiere 1996 ref.1409 6) Occupational asthma from inhalation of garlic fumes or dust. (Zuskin 1988 ref.57 549) (Falleroni 1981 ref.2197 2) Exercise-induced anaphylaxis.

This study reports on 7 garlic workers with occupational asthma from garlic dust. (Anibarro 1997 ref.1837 3)

Occupational allergic contact dermatitis (Kanerva 1996 ref.787 34) (Hughes 2002 ref.6816 0) One of the most frequent causes of fingertip dermatitis in caterers. Reactions may be immediate or delayed. (Campolmi 1982 ref.3496 8)

In evaluating 163 asthmatic children with food allergy for food-induced asthma, using DBPCFC the most frequent offending foods were, sometimes in association, peanut (30.6%), egg (23.1%), cow's milk (9.3%), mustard (6.9%), codfish (6%), shrimp (4.5%), kiwi fruit (3.6%), hazelnut (2.7%), cashew nut (2.1%), almond (1.5%), garlic (1.2%). (Rance 2002 ref.7671 1)

NON IMMUNE:
A patient who made reproduction antique china dolls complained that wherever she touched the dolls' heads when painting them, black speckles appeared after the subsequent firing. This study showed that the clay was rich in iron, and that the patient's sweat contained volatile sulphides whenever she ate garlic, and that the speckles consisted of iron and sulphur. The patient was shown to be a poor sulphoxidiser and was therefore unlikely to be able to excrete sulphur-containing breakdown products of garlic in her urine. The speckling phenomenon, which is not uncommon in 19th-century china dolls, is an example of an occupational hazard where the risk is to the product rather than the patient. (Harris 1986 ref.6647 1)

A patient with a second-degree burn of the forehead, induced by topical application of crushed garlic is reported. (Baruchin 2001 ref.6821 1) (Hviid 2000 ref.6824 2). Garlic burns may mimick herpes zoster. (Farrel 1996 ref.6881 1)

Garlic seems to have anti-microbial and immunostimulating properties; enhances fibrinolytic activity, and exert favorable effects on platelet aggregation and adhesion (Resch 1995 ref.2372 3)

Can reduce nasel congestion, lower blood pressure and blood cholesterol. Antiviral and antibacterial agent. May induce migraines.

A study by Boccafogli demonstrates that patients with grass pollen-allergic respiratory disease report adverse food reactions more frequently than patients allergic to Dermatophagoides.

Garlic-sensitive patients showed positive tests to diallyldisulfide, allylpropyldisulfide, allylmercaptan and allicin, all present in garlic. (Papageorgiou 1983 ref.1447 3)

More than 15 allergens were detected in this study of food-induced anaphylaxis: egg (11.6%), fish (10.4%), crustaceans (10.4%), milk (6.5%), fruit-latex group (6.5%), peanut and other legumes (soy, peas, lentils, guar gum, etc.), celery, garlic, etc. The food allergen still remained unknown in 25% of cases (Moneret-Vautrin)

Mustard oil and garlic extract inhibit chromosomal breaks due to sodium arsenite (arsenic), a contaminant in ground water. (Choudhury 1997 ref.2889 2)

The following common herbal remedies may increase the risk of bleeding during surgical procedures: feverfew, garlic, ginger, ginkgo, and Asian ginseng. (Pribitkin 2001 ref.4647 3)

Garlic produced dose-dependant diuretic, natriuretic and hypotensive effects in anaesthetized dogs (Pantoja 1991 ref.1440 3)

Garlic ingestion by pregnant women significantly alters the odor of their amniotic fluid. (Mennella 1995 ref.6884 1)

Infants of mothers who ingested garlic capsules were exposed to garlic volatiles in their others' milk and spent significantly less time breast-feeding compared with those infants whose mothers who did not. Moreover, the latter group of infants spent significantly more time attached to their mothers' breasts during the 4-h test session. (Mennella 1993 ref.6885 1)

Present in a herbal product, it may potentially increase the risk of bleeding or potentiate the effects of warfarin therapy. (Heck 2000 ref.7122 1)

Plausible cases of herb-drug interactions include: bleeding when warfarin is combined with ginkgo (Ginkgo biloba), garlic (Allium sativum), dong quai (Angelica sinensis), or danshen (Salvia miltiorrhiza). (Fugh-Berman 2000 ref.8380 1)