Keeping a severe form of pulmonary hypertension (PH) at bay may be as simple as including garlic in your diet, according to a study that suggested an ingredient in the spice may be the prophylactic component.1 The research was unveiled at Experimental Biology 2005, hosted by the Federation of American Societies for Experimental Biology, being held in early April in San Diego.
Pulmonary hypertension is a disease characterized by abnormally high blood pressure in the pulmonary artery, which connects the heart to the lungs. Symptoms include shortness of breath with little exertion, fatigue, chest pain, dizzy spells and fainting. The disease is termed primary pulmonary hypertension when it occurs without a known cause. By contrast, secondary pulmonary hypertension happens because of another disease like emphysema, bronchitis, Raynaud's phenomenon, or scleroderma. While the disease can be fatal, experts point out that new treatments are continually helping to improve a person's prognosis.2
Special Spice?
David Ku, PhD, a professor of Pharmacology at the University of Alabama, and his colleagues tested the garlic ingredient, known as allicin (AL-uh-sin) on a group of rats. The study not only pinpointed the effective ingredient in garlic, but also suggested that it achieves its protective effects by reducing tension in the arteries.
Ku and his team induced a form of pulmonary hypertension in the rats for the purposes of the research. Within three weeks, half of the animals developed chronic PH with significant increases in pulmonary artery pressure. But the rest of the animals, which were also induced with PH, experienced no such increase in blood pressure. That's because their diets had been supplemented with daily doses of allicin. It was this ingredient and not the garlic itself that helped protect the rats, Ku emphasized. "Feeding with garlic devoid of allicin failed to exert this effect," he said.
Possible Coronary Vessel Protection
In a related study presented at the same medical conference,3 Ku and his associates discovered that a diet including garlic fed to rats may also protect the healthy function of coronary blood vessels, those that connect the heart with other organs. Allicin was again responsible for this prophylactic effect. It also eased the severity of right heart hypertrophy, a significant effect of pulmonary hypertension involving an abnormal growth of one side of the heart caused by the stress of pumping blood through narrowed blood vessels.4 The condition is known in medical terms as cor pulmonale.
The studies were an extension from previous research that had suggested that garlic has health benefits for people. Studies have implied that garlic supplementation may help lower blood pressure,5 reduce cholesterol,6 and inhibit abnormal blood clotting.7
Does it Also Work for People?
Despite the apparently promising findings, Ku's team stresses that effects in rats do not always directly translate to humans. Ku says more research is needed to confirm that the beneficial effects of allicin also occur in humans relative to pulmonary hypertension. Still, in view of the low toxicity of garlic, including the spice in a person's diet each day seems reasonable, especially for people with respiratory and pulmonary ailments, Ku said.
The amount of garlic that provided the protective effect in the rodents was equivalent to two cloves per day, he said.
"These findings confirm our earlier reports and further demonstrate that garlic is also protective against the development of chronic pulmonary hypertension, and that the preservation of pulmonary endothelial vasoregulatory function may represent an important mechanism," wrote Ku's group.
1. Ku DD, Wu HC, Sun X. Garlic prevents monocrotaline pulmonary hypertension and preserves pulmonary endothelial function in rats. Experimental Biology 2005. 2005 Apr 2-6. San Diego, CA.
2. Pulmonary Hypertension Association. What is PH? Available at: http://www.phassociation.org/Learn/What-is-PH/index.asp. Accessed March 31, 2005.
3. Sun X, Ku DD. Garlic protects coronary endothelial function in monocrotaline-induced pulmonary hypertensive rats. Experimental Biology 2005. 2005 Apr 2-6. San Diego, CA.
4. Murphy ML, Dinh H, Nicholson D. Chronic cor pulmonale. Dis Mon 1989 Oct;35(10):653-718.
5. Garcia Gomez LJ, Sanchez-Muniz FJ. Review: cardiovascular effect of garlic (Allium sativum) [Translated from Spanish]. Arch Latinoam Nutr 2000 Sep;50(3):219-29.
6. Lau BH. Suppression of LDL oxidation by garlic. J Nutr 2001 Mar;131(3s):985S-8S.
7. Siegel G, Walter A, Engel S, Walper A, Michel F. Pleiotropic effects of garlic [Translated from German]. Wien Med Wochenschr 1999;149(8-10):217-24.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
