A number of studies have shown that garlic has an important impact on risk factors for cardiovascular disease. It has been demonstrated that people who make garlic a regular part of their diets enjoy lowered blood pressure and decreased platelet aggregation, as well as decreased levels of triglycerides and LDL (“bad”) cholesterol. Garlic also may increase HDL (“good”) cholesterol. Daily consumption of one half to one clove of garlic lowers LDL cholesterol levels by approximately 10 percent, partially by decreasing cholesterol absorption. Garlic extracts have also been shown to decrease blood pressure: In one study, a 5 percent decrease in systolic blood pressure and a slight decrease in diastolic pressure were recorded. Even these modest decreases, may result in a significant lessening of the risk for stroke and heart attack. The end result of all of these benefits is a lowered risk of atherosclerosis and heart disease as well as a reduced risk of heart attack and stroke. Garlic oil has been shown to decrease total and LDL cholesterol and triglyceride levels.
Garlic’s primary positive effect on cardiovascular disease comes from its sulfur compounds, but the effects of vitamin C, B6, selenium, and manganese can’t be ignored. Garlic’s vitamin C—the body’s primary antioxidant defender—protects LDL cholesterol from oxidation. It’s the oxidation of LDL cholesterol that begins the process that damages blood vessel walls. Vitamin B in garlic lowers levels of homocysteine, a substance that can directly damage blood vessel walls. The selenium in garlic may contribute to reducing the risk of heart disease, while it’s also working to protect against cancer and heavy metal toxicity. Manganese in garlic works in a variety of antioxidant defenses, and studies have found that adults deficient in manganese have lower levels of the “good,” or HDL, cholesterol.