Most species are perennials often with a rhizome or a bulb, especially in temperate countries (eg tulip, hyacinth, lily of the valley, onion, garlic, scille), they sometimes look like a tree or liana in hot countries (ex : aloe, yucca, dragon tree).
The allium genus includes several hundred species originating in the northern hemisphere.
Garlic is a small perennial with linear leaves and sheaths, probably native to Siberia but cultivated since ancient times in the Middle East, Egypt, Greece and China.
It adapts to many climates but gives the most beautiful harvests in temperate countries.
The bulb of garlic or head of garlic is formed of many "cloves" joined together and surrounded by a whitish membrane.
This bulb has usually developed around a mother clove that has dried out at the end of growth.
Garlic reproduces vegetatively but it also has flowers, red or white, arranged in umbels and seeds.
It is a very common food plant, a condiment marketed around the world but also has very interesting pharmacological and therapeutic properties.
CHEMICAL COMPOSITION AND PROPERTIES
Garlic cloves contain :
- reserve polysaccharides (fructans),
- amino acids,
- enzymes (aliinase, peroxidase),
- and especially sulfur compounds, which are responsible for the majority of pharmacological properties.
In fresh garlic, the main sulfur constituent is aliin (odorless), but as soon as the garlic is contused or crushed, an enzyme (aliinase) is released which degrades aliin.
The final product of this transformation is aliicin (with a strong smell), which is itself rapidly oxidized in the air and becomes diallyl disulfide (with a marked odor), the main constituent of the essence of garlic. ".
The aliicin can also be condensed, we then obtain secondary compounds, ajoenes, which are less pharmacologically active.
Cooking rapidly converts all these sulfur compounds into cyclic condensation products (vinyldithiine) within minutes, while it takes several hours at room temperature.
It is rather difficult to characterize the pharmacological action of each sulfur compound, it is generally preferred to speak of the properties of garlic without specifying the active compounds (with the exception of: aliicin, ajoenes).
Aliin is rapidly absorbed (10 min) and excreted in about 6 hours. Aliicin and condensation compounds are absorbed more slowly (1/2 to 2 hours) and persist longer in tissues (2 to 4 days).
Garlic has proven properties
Garlic has proven properties:
- anti-atheromatous, anti-hypertensive and anti-lipidemic,
- fibrinolytic and anti-platelet aggregation,
- and apparently protects against some digestive cancers.
Action on blood lipids, atheroma, blood pressure.
In ANIMALS (rat, chicken, rabbit studies) the consumption of garlic significantly lowers cholesterol and triglyceride levels.
In HUMANS, even if the experimental protocols are sometimes criticized, a 9 to 12% decrease in blood cholesterol level is usually observed after one month of treatment (600 to 900 mg of standardized garlic powder at 1.3% aliine, per day) and especially after 4 months of regular intake.
A favorable modification of the LDL / HDL RATIO (lipoproteins that carry cholesterol in the blood) is observed, with an increase in "good" lipoproteins (HDL) and a decrease in others.
At the same time, ATHROMA plaques appear to be reduced in area (10 to 20%) and in thickness (3%). However, this drop in blood cholesterol is only observed in moderate hypercholesterolemia and not in cases of familial or congenital diseases.
The effect on blood pressure is low to moderate: 5 to 7% decrease.
Fibrinolytic and anti-thrombotic action
Several actions combine to improve blood circulation, limit clot formation and the development of atheromatous plaque.
Platelet aggregation induced is markedly decreased (up to 30%) when cholesterolemia is normal or slightly increased (10-month study).
The plasma effect is rapid: it is noted 6 to 8 hours after absorption of 900 mg of garlic powder (standardized at 1.3% aliine) an improvement in the plasma viscosity and the capillary flow.
There is a rapid decrease in platelet aggregation and increase in fibrinolysis (up to 70%) for about 12 hours.
All this is of course very interesting to prevent disorders due to arteriosclerosis (embolisms, stroke, heart attack)
In vitro, the low molecular weight sulfur compounds (aliine and aliicine) increase the phagocytic activity and cytotoxicity of "killer cells", NK lymphocytes and K.
Synergistic action is observed with interleukin 2 (IL2).
Aliicin, a very active molecule, has:
- an antimicrobial effect on enterobacteria, some streptococci and staphylococci but apparently not on Helicobacter pylori (responsible for many gastric ulcers),
- an antiviral power,
a rather marked antifungal power on Candida albicans, Cryptococcus and Histoplasma. Ajoenes are also antifungal.
Protection against cancerous degeneration
Many studies (especially North American) suggest that a diet rich in garlic is associated with a lower risk of occurrence of gastrointestinal cancer .
The effect would be preventive rather than curative.
On the other hand, garlic is rich in selenium, some growers further increase this quality by artificially enriching the soil with selenium; we know the antioxidant power of this metalloid, some work suggests that it also helps prevent cancerous degeneration (perhaps also thanks to this antioxidant capacity).
The Egyptians advocated it as a panacea, medieval herbalist called it the "peasants' theriac". All ancient doctors cited it, in ancient Greece it was a symbol of physical strength.
For Chinese doctors, it is a "hot" plant, "bitter", active on the meridians large intestine, spleen and stomach; it is contra-indicated to the patient whose "yin" is deficient.
Garlic is known and advocated in traditional Arab, Ayurvedic medicines and recommended by all European and American pharmacopoeias.
Not bad for a condiment so commonplace, cheap and easy to find.
Indications derive from the pharmacological properties mentioned above:
- prevention and "treatment" of arteriosclerosis, moderate hypercholesterolemia and hypertension usually associated with it,
- prevention of cardiovascular disorders related to this situation of vascular sclerosis,
- improvement of the blood circulation and prevention of severe arteritic thromboses (lower limbs, coronaries) and minor circulatory disorders,
- intestinal "disinfection" in case of minor infection: moderate enteritis, digestive disorders related to intestinal fermentations. Garlic reduces the proliferation of germs more than it destroys them, in case of acute infection it does not replace major antibiotics,
- cutaneous mycosis, or cutaneous bacterial infections (garlic was successfully used during the Second World War by the Soviet army),
- its action on intestinal worms is controversial although classic; perhaps a repellent effect more than a toxic effect.
Children who support the consumption of raw garlic usually do not have intestinal parasitosis,
- prevention of digestive cancers: stomach and colon,
- some herbal therapists also recommend it in rhumatoid conditions, in infections of the upper respiratory tract (in combination with other phytomedicines or essential oils), the sulfur compounds of garlic are also eliminated by breathing.
Garlic juice or crushed garlic was disinfectant and slightly antibiotic but there are other local uses.
Garlic can help to remove corns: application for two weeks crushed garlic on the corn protecting the surrounding healthy skin with plaster.
Garlic oil soothes ear pain and inflammation and is useful for the treatment of cutaneous mycosis including those of feet and toes.
Fresh garlic but also standardized garlic powder, distillate or garlic essence, alcoholic tincture 1/5, oily maceration or garlic oil. According to the preparation the chemical composition is different.
Fresh garlic and garlic powder contain aliine and aliicin. Ajoene garlic oil and vinyldithiines, garlic oil of diallyl disulfide.
An average dosage would be the equivalent of 6 to 10 mg of aliine per day, ie:
1 clove of fresh garlic or 500 mg to 1 g of garlic powder.
For a more marked effect one can increase the dose by distributing it in the day is:
1 to 2 cloves of garlic 3 times a day or 500mg (1 capsule) 3 to 5 times a day.
It is recommended to do an extended or even unlimited treatment at low or medium dosage, or at high dosage 1 to 2 months renewed in the year.
Some herbal therapists recommend garlic alcoholic tincture 1/5, 20 to 30 drops a day, but the smell is particularly unpleasant.
Raw garlic is not always well tolerated, watch out for fragile stomachs.
Gastro-resistant garlic powder capsules, on the other hand, generally do not give rise to digestive disorders.
Garlic is not recommended for insomniacs, and also after recent surgery or transplant because of effects on blood clotting and immunostimulation.
A CONDIMENT WITH VERY MODERN THERAPEUTIC APPLICATIONS
Garlic used since antiquity, considered a long time ago as a panacea, is still very useful to fight modern ailments: arteriosclerosis and its complications, to reduce blood cholesterol, promote blood circulation and therefore prevent vascular accidents.
Recent studies suggest that regular consumption of fresh garlic or garlic powder prevent certain digestive cancers.
Copyright 2019 : Dr Jean-Michel Hurtel