Garlic May Lower Blood Pressure as well as Pharmaceuticals

Recent animal studies on garlic have found a blood pressure lowering effect and have identified the mechanism behind the action. (We reported on this research in our Nov. 2007 Newsletter, available here.) Still, human studies and "non-systematic reviews" have provided mixed results. A new systematic meta-analysis study published in June has found that garlic supplements reduce blood pressure as well as the most popular prescription medications. Previous meta-analysis work only included research conducted prior to 1994, leaving out nearly 14 years of research and 11 studies that are included in this new study.¹

All the 25 studies selected for this new meta analysis were randomized, placebo-controlled studies that gave the participants viable doses of standardized garlic extract ranging between 600mg and 900mg per day and for 12- to 23-week duration. The researchers pooled that data and found that the garlic supplements reduced systolic blood pressure (the "top" number, or 120, in a normal reading of "120 over 80") by 4.6mm of mercury on average. When the researchers limited the study to include only participants who had high blood pressure, average systolic blood pressure was decreased by 8.4mm of mercury and diastolic blood pressure was reduced by an average of 7.3mm of mercury. The researchers found that the higher the participant's blood pressure was at the beginning of the study, the greater the reduction that was achieved by taking the garlic.

These finding indicate that garlic supplements may be on par with the most popular prescription drugs used for treating high blood pressure. Beta blockers, likely the most popular, reduce systolic blood pressure by about 5mm of mercury on average, while ACE inhibitors, a newer generation of blood pressure regulation drugs reduce systolic blood pressure by about 8mm of mercury.

The researchers noted that reducing systolic blood pressure by 4 to 5 points and lowering diastolic blood pressure by 2 to 3 points in the population as a whole could reduce heart disease mortality by as much as 20 percent. Naturally, more long-term research will need to be conducted to determine what, if any, effect garlic could have on heart disease.

Learn more about the benefits of garlic on the cardiovascular system here.

1. Ried, K., O. R. Frank, et al. (2008). "Effect of garlic on blood pressure: a systematic review and meta-analysis." BMC Cardiovasc Disord 8: 13.