Garlic

Plant Part Used

Bulb

Introduction

From immune enhancement to cancer prevention, garlic may support health in many ways. What many people don’t know, however, is that there is some controversy about the most effective form of garlic people should take. One of the biggest concerns about garlic is whether it is still active by the time it gets to the shelf for purchase. It is important to select a garlic product that guarantees potency. Keep in mind that raw garlic is more potent than cooked garlic, because heat inactivates the enzyme allinase. Allinase gives garlic its odor and stimulates the formation of allicin, which scientists believe may be the key to garlic’s health-enhancing properties.

There are odorless garlic preparations that provide alliin, a precursor to allicin. Alliin is converted (to some extent) to allicin in the body and allows for efficacy without all the odor.

Interactions and Depletions

Interactions

Dosage Info

Dosage Range

400mg (standardized extract), 2 times a day, equivalent to 1200mg of fresh garlic OR 10mg of alliin providing 4mg of total allicin potential (TAP), daily; also, 600mg (standardized, aged extract), 1-3 times a day.

Most Common Dosage

400mg (standardized extract), 2 times a day equivalent to 1200mg of fresh garlic OR 10mg of alliin providing 4mg of total allicin potential (TAP), daily; also 600mg (standardized, aged extract), 2 times a day.

Standardization

[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]

The most current available medical and scientific literature indicates that this dietary supplement should be standardized to 10-12mg/gm alliin and 4mg of TAP per dose; aged garlic products should be standardized to contain 1mg/gm S-allyl cysteine (SAC) content per dose.

Reported Uses

Garlic’s usefulness in promoting overall health is wide-ranging. Many studies have suggested that garlic may aid in the prevention of such major cardiovascular conditions as heart disease, atherosclerosis, and stroke. These benefits are probably due to garlic’s ability to lower total cholesterol, LDL, or "bad," cholesterol and triglycerides, and increase HDL cholesterol, the so-called "good" cholesterol. (1) , (2) , (3) In addition, garlic may support the overall health of the circulatory system, which may play a role in lowering the risk of heart attack and stroke. (4) , (5) , (6) Rounding out garlic’s benefits for the cardiovascular system is its function as an antioxidant and its role in preventing stroke and arteriosclerosis. (7)

Garlic use has been reported to be useful in treating mild high blood pressure in both animal and human studies. (8) , (9) , (10) There are likely multiple reasons why garlic may lower blood pressure, (11) , (12) , (13) , (14) but many experts feel that further research should be performed in this area. (15)

Garlic has also shown promise in both the prevention and treatment of cancer. (16) Studies have found that cultures with a high garlic intake have comparatively low cancer rates. (17) Scientific studies have also suggested that garlic may inhibit the formation of nitrosamine, possibly reducing the role of nitrosamine in cancer. (18)

Studies have looked at garlic’s potential for fighting infection and detoxifying the body. The active components allicin and alliin may have anti-infective effects against bacteria and fungi. (19) , (20) , (21) Helicobacter pylori, the bacteria responsible for many peptic ulcers, is one species of bacteria that garlic has been reported to inhibit. (22) , (23) Garlic may also help in the detoxification of heavy metals from the body, including lead. (24)

Finally, studies have also shown that certain types of aged garlic have been reported to protect the liver from potentially harmful chemicals and drugs. (25) , (26) , (27)

Toxicities & Precautions

Introduction

[span class=alert]Be sure to tell your pharmacist, doctor, or other health care providers about any dietary supplements you are taking. There may be a potential for interactions or side effects.[/span]

General

This dietary supplement is considered safe when used in accordance with proper dosing guidelines. (28) However, large doses of this dietary supplement used over a long period of time are not recommended. (29)

Side Effects

Side effects are possible with any dietary supplement. This dietary supplement may cause the presence of garlic odor, stomach/intestinal distress or irritation may be present at the beginning of use. (30) Tell your doctor if these side effects become severe or do not go away.

Pregnancy/ Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Yet little is known about the use of this dietary supplement while pregnant or breast-feeding. Therefore, it is recommended that you inform your healthcare practitioner of any dietary supplements you are using while pregnant or breast-feeding.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Since young children may have undiagnosed allergies or medical conditions, this dietary supplement should not be used in children under 10 years of age unless recommended by a physician.

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  1) Botanical Info

References

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  2. View Abstract: Steiner M, et al. A Double-blind Crossover Study in Moderately Hypercholesterolemic Men that Compared the Effect of Aged Garlic Extract and Placebo Administration on Blood Lipids. Am J Clin Nutr. 1996;64(6):866-70.
  3. View Abstract: Agarwal KC. Therapeutic Actions of Garlic Constituents. Med Res Rev. 1996;16(1):111-24.
  4. View Abstract: Kiesewetter H, et al. Effect of Garlic on Platelet Aggregation in Patients with Increased Risk of Juvenile Ischaemic Attack. Eur J Clin Pharmacol. 1993;45(4):333-36.
  5. View Abstract: Bordia A. Effect of Garlic on Blood Lipids in Patients with Coronary Heart Disease. Am J Clin Nutr. 1981;34(10):2100-03.
  6. Bordia A, et al. Protective Effect of Garlic Oil on the Changes Produced by 3 Weeks of Fatty Diet on Serum Cholesterol, Serum Triglycerides, Fibrinolytic Activity and Platelet Adhesiveness in Man. Indian Heart J. 1982;34(2):86-88.
  7. View Abstract: Ide N, et al. Aged Garlic Extract Attenuates Intracellular Oxidative Stress. Phytomedicine. May1999;6(2): 125-31.
  8. Cheng W. Clinical and Experimental Study of Garlic in Preventing and Treating Cardiovascular Diseases. Zhong Xi Yi Jie He Za Zhi. Oct1990;10(10):635-7, 640.
  9. View Abstract: Ali M, Al-Qattan KK, Al-Enezi F, et al. Effect of Allicin from Garlic Powder on Serum Lipids and Blood Pressure in Rats Fed with a High Cholesterol Diet. Prostaglandins Leukot Essent Fatty Acids. Apr2000;62(4):253-9.
  10. View Abstract: Sharifi AM, Darabi R, Akbarloo N. Investigation of antihypertensive mechanism of garlic in 2K1C hypertensive rat. J Ethnopharmacol. Jun2003;86(2-3):219-24.
  11. View Abstract: Pedraza-Chaverri J, Tapia E, Medina-Campos ON, et al. Garlic Prevents Hypertension Induced by Chronic Inhibition of Nitric Oxide Synthesis. Life Sci. 1998;62(6):PL71-7.
  12. View Abstract: Dirsch VM, Kiemer AK, Wagner H, et al. Effect of Allicin and Ajoene, Two Compounds of Garlic, on Inducible Nitric Oxide Synthase. Atherosclerosis. Aug1998;139(2):333-9.
  13. View Abstract: Kaye AD, De Witt BJ, Anwar M, et al. Analysis of Responses of Garlic Derivatives in the Pulmonary Vascular Bed of the Rat. J Appl Physiol. Jul2000;89(1):353-8.
  14. View Abstract: Ali M, Thomson M, Alnageeb MA, et al. Antithrombotic Activity of Garlic: Its Inhibition of the Synthesis of Thromboxane-B2 During Infusion of Arachidonic Acid and Collagen in Rabbits. Prostaglandins Leukot Essent Fatty Acids. Oct1990;41(2):95-9.
  15. View Abstract: Silagy CA, Neil HA. A Meta-analysis of the Effect of Garlic on Blood Pressure. J Hypertens. Apr1994;12(4):463-8.
  16. View Abstract: Thomson M, Ali M. Garlic [Allium sativum]: a review of its potential use as an anti-cancer agent. Curr Cancer Drug Targets. Feb2003;3(1):67-81.
  17. View Abstract: Dorant E, et al. Garlic and Its Significance for the Prevention of Cancer in Humans: A Critical View. Br J Cancer. 1993;67:424-29.
  18. View Abstract: Dorant E, et al. Garlic and Its Significance for the Prevention of Cancer in Humans: A Critical View. Br J Cancer. 1993;67:424-29.
  19. View Abstract: Adetumbi M, et al. Allium sativum (Garlic)--A Natural Antibiotic. Med Hypoth. 1983;12:227-37.
  20. View Abstract: Yoshida H, Iwata N, Katsuzaki H, et al. Antimicrobial Activity of a Compound Isolated from an Oil-macerated Garlic Extract. Biosci Biotechnol Biochem. May1998;62(5):1014-7.
  21. View Abstract: Pai ST, et al. Antifungal Effects of Allium sativum (Garlic) Extract Against the Aspergillus Species Involved in Otomycosis. Lett Appl Microbiol. 1995;20(1):14-18.
  22. View Abstract: Cellini L, et al. Inhibition of Helicobacter pylori by Garlic Extract (Allium sativum). FEMS Immunol Med Microbiol. Apr1996;13(4):273-77.
  23. View Abstract: Canizares P, Gracia I, Gomez LA, Martin de Argila C, de Rafael L, Garcia A. Optimization of Allium sativum solvent extraction for the inhibition of in vitro growth of Helicobacter pylori. Biotechnol Prog. Nov2002;18(6):1227-32.
  24. View Abstract: Hanafy MS, et al. Effect of Garlic on Lead Contents in Chicken Tissues. DTW Dtsch Tierarztl Wochenschr. Apr1994;101(4):157-58.
  25. View Abstract: Wang BH, Zuzel KA, Rahman K, et al. Protective Effects of Aged Garlic Extract Against Bromobenzene Toxicity to Precision Cut Rat Liver Slices. Toxicology. Apr1998;126(3):213-22.
  26. View Abstract: Dwivedi C, John LM, Schmidt DS, et al. Effects of Oil-soluble Organosulfur Compounds From Garlic on Doxorubicin-induced Lipid Peroxidation. Anticancer Drugs. Mar1998;9(3):291-4.
  27. View Abstract: Sumioka I, Matsura T, Kasuga S, et al. Mechanisms of Protection by S-allylmercaptocysteine Against Acetaminophen-induced Liver Injury in Mice. Jpn J Pharmacol. Oct1998;78(2):199-207.
  28. View Abstract: Nakagawa S, et al. Acute Toxicity Test of Garlic Extract. J Toxicol Sci. 1984;9:155-69.
  29. Rakel: Conn's Current Therapy 2001, 53rd ed. W B Saunders Company; 2001:1267.
  30. View Abstract: Berthold HK, Sudhop T, von Bergmann K. Effect of garlic oil preparation on serum lipoproteins and cholesterol metabolism: a randomized controlled trial. JAMA. Nov1998;279(23):1900-2.