For thousands of years, various cultures have used garlic as both a food and medicine to prevent or treat a wide array of diseases and conditions. Today, garlic is used for various conditions related to the heart and blood system, including high cholesterol, hardening of the arteries and high blood pressure. Because garlic may have effects on blood pressure and cause possible drug interactions, consult your doctor before taking garlic with blood pressure pills.
Treatment
High blood pressure, or hypertension, is usually without symptoms, but it can cause serious health problems, including stroke, heart failure and kidney disease. Hypertension is usually treated through healthy lifestyle habits, including watching your diet, regular exercise and weight loss. If these cannot control your high blood pressure, you may need blood pressure pills. These medicines work in different ways to lower your blood pressure, such as removing extra water from your body or widening your blood vessels.
Function
An important component of garlic is an odorless sulfur-containing substance called alliin, which comes from the amino acid cysteine. When you chew or otherwise crush garlic, the alliin is converted to another compound, allicin. Allicin is the main active substance that gives garlic its odor and health benefits. Because allicin is not absorbed well when taken by mouth, garlic is fermented, or aged, to break down allicin into more absorbable components.
Effects
Several studies have reported that garlic taken by mouth can lower blood pressure. A study published in the journal "Hypertension" in 1994 reviewed seven human trials of garlic preparations to determine the effect of garlic on blood pressure compared to placebo sugar pills. Results of these trials showed that garlic produced significant blood pressure-lowering effects when compared to the placebo in people with mild high blood pressure.
Considerations
Because garlic may lower your blood pressure, if you take garlic with your other blood pressure pills, it may enhance the effect of these medicines and cause your blood pressure to be too low. Low blood pressure may cause problems, such as dizziness, fainting and, in severe cases, shock. Garlic may also increase how quickly your liver breaks down some blood pressure medications, such as the calcium channel blockers diltiazem, nicardipine and verapamil, which may decrease the effectiveness of these medications.
References
- University of Maryland Medical Center: Garlic
- National Institutes of Health: Garlic
- National Institutes of Health: Blood Pressure Medicines
- "Journal of Hypertension"; A meta-analysis of the effect of garlic on blood pressure; C Silagy, et al.; Apr 1994
- National Institutes of Health: Low Blood Pressure
