Decreasing Arterial Plaque
Garlic contains many phytochemical antioxidants that prevent oxidation in the cardiovascular system. One probable cause of atherosclerosis, the build-up of plaque in arteries, is damage done by free radicals in our blood vessels and arteries. A 2004 study titled "The Natural Treatment of Hypertension," by A.J. Wilbourn, D.S. King, J. Glisson, R.W. Rockhold and M.R. Wofford concluded that "it is possible that reduced peroxidation processes may play a part in some of the beneficial effects of garlic in atherosclerotic diseases." Garlic was shown to decrease many cardiovascular risk factors including blood pressure, cholesterol, platelet aggregation and adhesion. A second 2004 study by I. Durak, M. Kavutou, B. Aytac, et al, showed that garlic inhibits vascular calcification, which is a marker of plaque formation in arteries, in rabbits. With less plaque build up in arteries, blood has fewer obstacles to normal circulation and blood pressure is decreased.
Anticoagulant Activity
In addition to inhibition of plaque formation, an anti-clotting effect has been seen with garlic supplementation. Any of the numerous organosulfur antioxidant compounds could be involved in this health-promoting effect. It is believed that the gamma-glutamylcysteine is a natural ACE inhibitor. ACE stands for angiotensin-converting enzyme, a notable factor in clotting disorders. Medline Plus reports that several human trials have shown anti-platelet or blood-thinning effects with garlic use. So much, in fact, that those on blood-thinning drugs must avoid excessive garlic consumption because it can exacerbate bleeding. This anti-coagulant effect can decrease the risk of high blood pressure.
Vasodilation
Many experts recognize the multiple hypotensive actions of garlic, though many of them are not completely understood. Garlic may reduce blood pressure by increasing vasodilation, which is the relaxing of blood vessels that allows blood to circulate more freely. However, garlic does not cause vasodilation through production of nitric oxide (NO) in endothelial cells. Garlic's action as a vasodilator works through an unknown mechanism. Professor David Julius, vice-chair of the Department of Cellular and Molecular Pharmacology at the University of California, believes that this effect occurs as a result of the activation of the TRPA1 channels on sensory neurones.
