Garlic is a member of the lily family closely related to onions and leeks. Garlic has been cultivated for thousands of years for its therapeutic benefits by the ancient Egyptians, Greeks, Romans, Indians and Chinese. Primary use of garlic was as a treatment for tumors, headaches, weakness and fatigue, wounds, sores and infections. It was regarded as a physically enhancing tonic, and was used by the first Olympic athletes as an energizer.
The scientific community has long respected garlic as a plant possessing impressive therapeutic activity. Louis Pasteur first demonstrated garlic’s anti-bacterial properties in 1858, and later Albert Schweitzer used garlic to treat amoebic dysentery. More recently, researchers have demonstrated that garlic helps protect against heart disease and cancer, and possess remarkable antibiotic effects. Garlic juice and its constituents can slow or kill more than sixty fungi and twenty types of bacteria, including some of the most virulent known to man.
Researchers really began studying garlic after results of an epidemiologic study were published about ten years ago. The long-term study compared three groups of vegetarians in India who: 1. Consumed little or no garlic at all; 2. Consumed moderate amounts (10 grams per week) of garlic, or; 3. Consumed large amounts (50 grams of garlic per week).
The mean fasting cholesterol levels for those ingesting large amounts of garlic was 159 mg/100 ml of serum. For those ingesting moderate amounts, the level was 172 mg/100 ml of serum, and those ingesting no garlic serum cholesterol levels were 208 mg/100 ml of serum.
The diet of all three groups was virtually identical except for the difference in garlic intake. Researchers also reported that those who abstained completely from garlic and onions had blood that clotted more quickly than did those who consumed garlic and onions.
In a another study, two sets of patients suffering with coronary-artery disease were enlisted in a ten-month study. One group got garlic supplements while the other group did not. Those who received garlic had steadily declining levels of lipoproteins associated with heart disease, while the group that didn’t get garlic showed no decline in these lipoproteins.
Researchers concluded: “The positive reports appear to be overwhelming. The reviewers were surprised by the scarcity of negative reports.” Scientists also reviewed a variety of animal studies, many well controlled, in which garlic clearly exhibited a statistically significant lowering effect on cholesterol. The effect in most studies was found to be “dose-related,” meaning that the higher the daily dose of garlic, the greater the reduction in cholesterol.
Various sulfur compounds contained in garlic appear to account for this favorable effect on cardiovascular health. Some of these are known to have significant impact on the biosynthesis of fatty acids, cholesterol, triglycerides and phospholipids. Ajoene, a garlic compound, has a potent anti-clotting effect and appears to be the crucial component in a number of garlic’s therapeutic actions.
Other compounds in garlic have exhibited anti-tumor effects in animals. Epidemiologic studies in China show that eating a lot of garlic can protect against stomach cancer. Those who ate an average of seven garlic cloves a day had an incidence of gastric cancer ten times lower than those who rarely, if ever, ate garlic. The garlic, in this case, seemed to work, at least in part, by preventing dietary nitrites from converting to cancer-causing nitrosamines.
Animal cancer research with garlic is impressive. Researchers recently proved that a garlic compound, diallyl sulfide, given to mice prior to exposure to a colon-cancer-inducing agent, has a potent protective effect. The garlic-treated animals got 75 percent fewer tumors than control animals not given garlic. In a similar experiments garlic completely protected mice against esophageal cancer. In other animal research, sulphur compounds of garlic have inhibited stomach and skin cancers.
These compounds seem to work by enabling the liver to detoxify cancer causing chemicals before they can do harm. Additionally, garlic contains bioflavonoids and antioxidants, both known anti-carcinogens. Allicin is another of the active sulfur compounds in garlic, and is the substance that gives garlic its antibiotic qualities.
There is one study which suggests that high doses of garlic might also increase physical endurance. Researchers wanted to see if garlic could protect heart muscles against a toxic drug. They injected rats with the heart-damaging drug isoproterenol. One group of these rats got garlic in their diet for a week prior to the injection with the drug. Another group got the drug, too, but no garlic. The garlic-fed rats withstood the effects of the drug far better than the rats that didn’t get garlic. The garlic-protected rats showed their greater physical endurance by swimming an average of 840 seconds before and 560 seconds after the drug injection. The rats that didn’t get garlic could swim only an average of 480 seconds before and only 78 seconds after injection. At autopsy, far fewer lesions were found in the heart muscles of the garlic-supplemented rats than in the muscles of the control rats.