Garlic

Plants do not have immune systems to defend themselves against the bacteria, fungi, viruses and yeasts that attack them. Their defense is direct chemical warfare. Their weapons are antibiotics, antivirals and fungicides that they manufacture internally. Their success is demonstrated by the fact that you see healthy growing plants everywhere.

In the case of garlic, one of the main active ingredients is a thiosulfinate compound called allicin. The manufacture of allicin is triggered by the release of enzymes by breaking the cell walls of the garlic plant. Allicin is the pungent, hot, stinky stuff that makes garlic special. In addition to allicin, garlic contains over 100 other beneficial nutrients. These include beta-carotene, folate, beta-sitosterol, ferulic acid, geraniol, oleanolic acid, P-coumaric acid, rutin, quercetin, thiamine, niacin, vitamin c, cysteine, zinc, calcium, magnesium, manganese, selenium, and others.

Garlic is an Anti-biotic and Anti-viral

In vitro (in laboratory cultures) studies demonstrate that garlic has antibacterial, antiviral, and antifungal activity. In one Clinical study, one capsule daily of an allicin-containing garlic supplement was tested on a group of 146 volunteers (Josling P 2001). Over several months half the group received the garlic while the other half got a placebo. The placebo group had 63 percent more common cold infections than the garlic group. In addition, those in the garlic group who did catch a cold had symptoms for an average of only 1.52 days, compared with 5.01 days for the placebo group. The doctors who conducted this garlic study concluded, "An allicin-containing supplement can prevent attack by the common cold virus."

Garlic in Herpes Virus Infections

While garlic has demonstrated in vitro anti-viral activity against many viruses including HSV-1 and HSV-2, clinical trials on humans have not been performed. Garlic's in vitro success against these viruses and its demonstrated in vivo effectiveness against the common cold virus suggests that it may be effective against the herpes viruses in humans as well. However, this hypothesis has not been clinically tested and, until it is, such claims cannot be made.

Garlic Lowers Blood Pressure

There is some evidence that garlic is mildly hypotensive in humans. Researchers at the University of Mississippi and in Turkey performed clinical tests on the effectiveness of garlic in reducing blood pressure. They found that garlic reduced systolic blood pressure by at least 9 mmHg and diastolic blood pressure by at least 5 mmHg. The effect was most noted in subjects with high blood pressure and high cholesterol. No hypotensive effect was observed in patients with normal blood pressure.

Garlic for Lowering Cholesterol

There is contradictory evidence as to whether garlic actually lowers cholesterol and triglyceride levels or not. The contradictions appear to arise from the use of different dosages, forms of garlic and other procedural differences. However, most findings showed that garlic slightly lowered blood cholesterol, LDL cholesterol and triglycerides with a consistent lowering of blood lipids seen in studies that used aged garlic extract (kyolic) as the supplement.

Research has demonstrated that garlic inhibits the peroxidation of lipids. This, in turn, prevents LDL cholesterol from being oxidized into harmful compounds. Garlic also lowers homocysteine levels. Recent research has identified homocysteine as a major culprit in heart disease, osteoporosis, alzheimers and several other degenerative diseases.

Garlic in Atherosclerosis

Garlic reduces platelet aggregation, thrombin formation, platelet adhesion to fibrinogen and the risk of thrombosis. Garlic's effects are attributed to allicin, ajoene, and other organosulfur constituents in the herb. A recent study on garlic confirms that it exhibits powerful fibrinolytic activity both in vitro and in vivo. In this study, it acted as an anticoagulant by downregulating thrombin formation. These effects reduce the formation of atherosclerotic plaque.

In one study, patients with atherosclerosis had higher plasma levels of the oxidant MDA ( malondialdehyde ) and lower plasma levels of the antioxidant enzyme glutathione peroxidase compared to the control group. However, those patients who consumed 1 ml/kg of garlic extract had significantly lowered MDA levels even in the absence of changes in antioxidant enzyme activities. In addition, the researchers found the presence of oxidant stress in blood samples from atherosclerosis patients, but ingesting garlic extract prevented oxidation reactions by eliminating this oxidant stress.

Garlic and Men's Health

Garlic may reduce the risk of prostate cancer, according to a recent study. Researchers surveyed 238 men with prostate cancer and 471 healthy controls in Shanghai, China to determine their eating habits. The risk of prostate cancer declined by more than 33 percent in men who consumed small amounts of onions, garlic, scallions, shallots and leeks each day. Men who consumed 2 grams of garlic daily experienced a 50 percent decease in prostate cancer risk.

Another study done with rats demonstrated that garlic supplementation in combination with a high protein diet increased testosterone levels.

Anti-Cancer Properties of Garlic

Modern epidemiological studies, well correlated with laboratory investigations, corroborate the evidence that higher intake of garlic and its relatives is correlated with reduced risk of several cancers. The mechanisms proposed to explain the cancer-preventive effects of garlic include inhibition of tumor mutagenesis, modulation of enzyme activities, and effects on cell proliferation and tumor growth. Several garlic compounds, including allicin, induce apoptosis (programmed cell death) in various malignant human cells. These include breast, colorectal, hepatic, prostate, and lymphoma cells. A growing number of clinical studies are examining the properties of ajoene, one of the major components of purified garlic. Researchers are investigating ajoene in part because it is more chemically stable than allicin. The list of cancers responding to garlic treatment or supplementation continues to grow.

Garlic Dosage

People who wish to consume garlic and have no aversion to its odor can chew from one to two whole cloves of raw garlic daily. In certain regions of China up to eight cloves of raw garlic are consumed per day. For those who prefer it with less odor, enteric-coated tablets or capsules with approximately 1.3% allacin are available. Clinical trials have used 600-900 mg (delivering approximately 5-6 mg of allicin ) per day in two or three divided amounts. Aged-garlic extracts have been studied in amounts ranging from 2.4-7.2 grams per day.

Garlic Side Effects and Drug Interactions

Garlic has anti-coagulant properties. Anyone with a bleeding disorder or taking anti-coagulant or anti-platlett medications should consult their doctor before consuming garlic. Examples of such medications include indomethacin, dipyridamole, and aspirin. Anyone anticipating surgery, child birth, etc. should avoid garlic.

Garlic may lower blood sugar considerably and may potentize the effect of certain anti-diabetic medications. Medications from this class include chlorpropamide, glimepiride, and glyburide. When using garlic with these medications, blood sugars must be followed closely and garlic use should be used under your doctor's advise.

Garlic may reduce blood levels of protease inhibitors. Protease Inhibitors are a class of drugs used to treat people with the human immunodeficiency virus (HIV). They include indinavir, ritinavir, and saquinavir.

It is hhypothesized by some that garlic may behave similarly to a class of cholesterol lowering medications called statins and to a class of blood pressure lowering medications called ACE inhibitors. Examples of these medications include atorvastatin, pravastatin, lovastatin, enalapril, captopril, and lisinopril. Possible interactions with these medications has not been tested.

Other side effects from garlic may include upset stomach, bloating, bad breath, and body odor.

Garlic is considered to have very low toxicity and is listed as Generally Recognized as Safe (GRAS) by the Food and Drug Administration (FDA) of the United States.

More research with better-designed studies is needed in order to fully assess the safety and effectiveness of garlic and to determine the most appropriate dose and form.

Recommended Garlic Products

The most direct way to use garlic is to simply eat the cloves directly. To get the benefits from eating raw garlic, it must be chewed thoroughly to release the allacin. This can be very "hot" and spicey. This combined with the odor can discourage the less dedicated. Alternatively, garlic is available in supplement form.

Optimized Garlic From the Life Extension Foundation

Garlic Related Articles in Life Extension Magazine

How Aged Garlic Extract Can Slash Heart Disease Risk, Scientifically reviewed by Dr. Gary Gonzalez, MD, in May 2022. Written by: Michael Downey, Health & Wellness Author.

Garlic, Scientifically reviewed by: Holli Ryan, RD, LD/N, in March 2021. Written by: Life Extension Editorial Staff.

Garlic extract, Gastritis, Melatonin, and Menopause, Scientifically reviewed by Dr. Gary Gonzalez, MD, in May 2022. Written by: Life Extension Editorial Staff.

Phytonutrients, Scientifically reviewed by: Dr. Gary Gonzalez, MD, in January 2021. Written by: Life Extension Editorial Staff.

Garlic References

Click to Expand References

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