Could small daily doses of common kitchen staple onions support long-term heart health? New clinical findings suggest so - the flavonoid quercetin in onion peel extract improved endothelial function markers in just 3 months.  

A landmark double-blind, placebo-controlled trial examined whether taking an onion peel extract (OPE) supplement containing the flavonoid quercetin could improve cardiovascular function in 72 healthy but overweight or obese adults aged 30-70 years.¹ Participants were randomly split into two groups receiving either 100 mg quercetin daily from OPE capsules or visually identical placebo capsules over 12 weeks.² Researchers measured endothelial function through flow-mediated dilation (FMD) percentages and circulating reparative endothelial progenitor cells (EPCs) counts at the start and end.

After 12 weeks, the OPE group increased flow-mediated dilation from 12.5% to 15.2%, indicating enhanced blood vessel flexibility and vasodilation. Placebos showed no improvement. Additionally, EPCs essential for repairing and regenerating blood vessel linings significantly increased from 44.2 per microliter at baseline to 52.3 after OPE treatment. This endothelial progenitor cell enhancement highlights an exciting regenerative frontier for combating cardiovascular disease, rather than just symptom management or attempting to suppress surrogate markers of disease progression. Most pharmaceutical interventions simply aim to slow CVD pathogenesis rather than regenerating damaged endothelial tissue. However, by boosting endogenous vascular repair processes, onion extracts offer true endothelial-healing potential.  

Together these data showcase daily oral onion peel extract providing cardiovascular benefits in as little as 3 months for overweight adults vulnerable to endothelial dysfunction. Boosting endothelial nitric oxide bioavailability through onion’s anti-inflammatory quercetin polyphenols likely stimulated observed vascular improvements. So consider embracing onions’ unexpected heart-supporting potential in easy, sustainable ways – like enjoying quercetin-concentrated peel extracts.  

To learn more ways to address endothelial dysfunction, visit our database on the subject here.

To learn more about the profound health benefits associated with onion and its most researched phytocompound quercetin, visit our database on the subject here. 

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References  

1. Eun-Yong Choi et al., “Effect of Onion Peel Extract on Endothelial Function and Endothelial Progenitor Cells in Overweight and Obese Individuals,” Nutrition 31, no. 9 (September 2015): 1131–35, https://doi.org/10.1016/j.nut.2015.04.020.  

2. Julie Ann Sosa Barrios, “Endothelial Progenitor Cells for Diagnosis and Prognosis in Cardiovascular Disease,” Stem Cells International 2018 (2018): 5046370, https://doi.org/10.1155/2018/5046370.