Cardiovascular disease is a major concern in modern society, with coronary heart disease being the number one cause of death in the United States today, according to the American Heart Association. Garlic is an herb with a long history of use and has a lot of promise for prevention or treatment of heart disease through its effects on various risk factors.
Garlic History
Garlic has been used medicinally for thousands of years, and according to a review of its medicinal history published in the Journal of Nutrition it was used for heart disorders as far back as 3,500 years ago in ancient Egypt. Other medicinal traditions have also used garlic for treating the heart. Recent research has focused on exactly how garlic affects different aspects of cardiovascular disease.
Blood Lipids
Abnormal blood lipids--including cholesterol--are known risk factors for heart disease. Garlic has been shown in some studies to decrease LDL, or bad, cholesterol. Most researchers agree that garlic has a much more potent effect on raising HDL, or good, cholesterol, which is of importance for lowering heart disease risk. For example, a 2008 study published in the Journal of Atherosclerosis and Thrombosis found that 600 mg of garlic extract daily significantly increased HDL cholesterol and lowered LDL cholesterol. However, several meta-analyses, including one published in June 2009 in the journal Nutrition Research Reviews, have found no statistically significant effects on cholesterol.
Blood Pressure
Garlic has been shown in some trials to have a beneficial effect on lowering blood pressure, which is another risk factor for cardiovascular disease. For example a 2009 study published in the journal Hypertension Research found that time-released garlic supplementation significantly decreased both systolic and diastolic blood pressure, while regular garlic extract significantly decreased systolic blood pressure. As with garlic's effect on blood lipids, there is a lot of controversy regarding its exact effects on blood pressure.
Platelet Aggregation
Platelet aggregation is when platelets--small cells in the blood--come together to produce blood clots. If this occurs abnormally in blood vessels leading to the heart, it can result in events such as heart attacks. Multiple studies such as one published in 2008 in the journal Pharmacology have shown that garlic can have a beneficial effect on reducing this clotting activity.
Directions for Use
A dose of at least 500 mg per day of a good quality garlic extract containing 2 to 5 percent of the active ingredient allicin is required to see any beneficial effects.
Considerations
The reason for the extreme variability in results in clinical trial can be attributed in part to the wide variety of garlic extracts used. Garlic that claims to be odorless likely has no effect on heart disease, as it is missing the component that produces the benefits for heart health.
The most common side effect is body odor. The National Institutes of Health cautions that there may be other side effects such as increased bleeding and changes in blood sugar as well as some drug interactions.
The research definitely suggests that garlic is good for your health. But check with your health care provider before using any garlic supplements.
References
- Nutrition Research Reviews: "The Impact of Garlic on Lipid Parameters: A Systematic Review and Meta-Analysis"
- Pharmacology: "Antiplatelet Activity of Allium ursinum and Allium sativum"
- Hypertension Research: "Time-Released Garlic Powder Tablets Lower Systolic and Diastolic Blood Pressure in Men with Mild and Moderate Arterial Hypertension"
- Journal of Nutrition: "Historical Perspective on Garlic and Cardiovascular Disease"
- Journal of Atherosclerosis and Thrombosis: "Lipid-lowering Effects of Time-Released Garlic..."
