The review, published in Nutrition Reviews, points out that cardiovascular disease is increasing in prevalence at an unprecedented rate and is thought to account for more than 17.3 million deaths and nearly US $863 billion annually.
Prior evidence has suggested that ingestion of quercetin - a plant pigment found in foods such as onions, teas, apples and red wine - confers health-promoting effects such as anticoagulatory, anti-inflammatory, antihypertensive, and antihyperglycemic activities and has positive effects on disorders of lipid metabolism.
Several clinical trials examining the influence of quercetin supplementation on the prevention and treatment of chronic diseases, especially CVD, have been completed. However, a team of researchers from Southern Medical University, in China, believed these findings have not been consistent.
Led by Haohai Huang, the team reviewed 17 studies, with a total of 886 participants, that assessed the impact of quercetin on blood pressure and glucose levels. Each study assessed blood glucose, total cholesterol, and/or insulin.
The pooled result from 13 treatment arms throughout the studies showed that quercetin markedly reduced systolic blood pressure.
Participants who consumed quercetin for eight weeks or more showed significantly changed levels of high-density lipoprotein cholesterol.
Quercetin did not markedly influence total cholesterol, or significantly alter fasting blood glucose concentrations and was not found to cause serious adverse events in any of the included studies.
The review concluded that a reduction in blood pressure of more than 10 mmHg lowers cardiovascular risk by 50% for heart failure, 35% - 40% for stroke, and approximately 20% to 25% for myocardial infarction.
Researchers here found that the favourable effects of quercetin on blood pressure support the use of quercetin for patients with hypertension.
Source: Nutrition Reviews
Haohai Huang et al,
"Effect of quercetin supplementation on plasma lipid profiles, blood pressure, and glucose levels: a systematic review and meta-analysis"