Cardiac hypertrophy is a thickening of the heart wall, a muscle called the myocardium. Although athletic activity and pregnancy may temporarily cause an enlargement of the heart due to increased work load, over time hypertension and atherosclerosis can lead to abnormal thickening of the myocardium and may eventually cause congestive heart failure.40-41
Building on research suggesting quercetin’s therapeutic and preventive effects on cardiovascular disease, researchers in 2009 conducted an animal study to determine if quercetin could prevent cardiac hypertrophy. The rats were separated into two groups and all underwent a surgical procedure where randomly half had surgical restriction (by suture thread) of their aorta (to induce high blood pressure) and half did not. Next, subjects were randomly assigned to one of three groups: non-quercetin group, 5-mg/day quercetin, or 10-mg/day quercetin (added to their water supply, which did not inhibit water intake).41
Although the quercetin dosages given did not result in any blood-pressure lowering effect, it significantly suppressed the production of various proteins known to promote cardiac hypertrophy. Actual measurements of heart weights revealed that while the aorta-restricted, non-quercetin group experienced a 23% increase in heart size compared to the non-restricted control group, there was virtually no difference in heart size between the control group and those aorta-restricted rats treated with 10 mg of quercetin a day after 3 weeks. Certain prescription medications such as calcineurin inhibitors can also block cardiac hypertrophy, but they frequently cause toxicity in the kidneys and suppress the immunity. In comparison, quercetin exhibited no such side effects.41
Notably, nitric oxide has also been shown to be anti-hypertrophic.40 Although this study did not test for quercetin’s effect on nitric oxide, other studies have demonstrated that quercetin’s promotion of nitric oxide production by endothelial cells, which may significantly lower risk of atherosclerosis.33 Cardiac hypertrophy is defined by sustained dysfunctional cardiomyocyte and endocardial cells in the heart—cells that also produce nitric oxide molecules.40 Conceivably promotion of nitric oxide in these cells may be yet another mechanism by which quercetin may suppress this potentially deadly condition.
High blood pressure levels.
Commonly referred to as clogged arteries.
The inside lining of blood vessel walls.
Heart muscle cells.
Heart valve cells.