Data published in Phytotherapy Research indicated that while both the red wine extract of onion and red wine improved antioxidant activity, only the red wine extract of onion decreased total and LDL cholesterol levels after ten weeks.
“Numerous reports indicate that both red wine and onion can act as hypolipidemic agents,” wrote the researchers. “Flavonoids and alkyl sulfoxide compounds in onion (quercetin and myricetin) may increase fecal excretion of cholesterol and bile acids, thereby, decreasing total cholesterol levels.”
The study was funded by the Taiwan Tobacco and Liquor Corporation.
The Taiwanese scientists recruited 23 hypercholesterolemic (elevated cholesterol levels) but otherwise healthy volunteers and randomly assigned to drink either 250 mL of the red wine extract of onion or red wine for 10 weeks. While no significant changes in body weight, body mass, or BMI were observed, the researchers did note that both interventions increased the antioxidant activity, and that this was associated with an increase in the lag time of low-density lipoprotein oxidation.
“Red wine extract of onion and red wine intake showed 40.3% and 31.3% increases in lag time of LDL oxidation [respectively],” wrote the researchers. “[This] suggested that Red wine extract of onion treatment was superior to red wine treatment for prolonging the lag time of LDL oxidation.
“Several studies have confirmed that the intake of wine (resveratrol) or onions (quercetin, alkyl sulfoxides, and di-propyl trisulfide) effectively increases the antioxidant capacity; thereby, it delays or reduces susceptibility to LDL oxidation and subsequent cardiovascular events.”
Measures of blood lipid levels showed that only the red wine extract of onion decreased LDL and total cholesterol levels at 10 weeks.
Consumption of the red wine extract of onion was also associated with improvements in various inflammatory markers.
“[W]e conclude the cardioprotective effect of red wine extract of onion was well influenced by hypocholesterolemic, antioxidant, and anti-inflammatory,” wrote the researchers. “In the future, the mechanism(s) behind the cardioprotective effects of red wine extract of onion were revealed by isolating the active components of red wine and onion.
Source: Phytotherapy Research
Published online ahead of print, doi: 10.1002/ptr.5537
“Cardioprotective Efficacy of Red Wine Extract of Onion in Healthy Hypercholesterolemic Subjects”
Authors: H-F. Chiu, et al.