Impact of Flavonols on Cardiometabolic Biomarkers: A Meta‐Analysis of Randomized Controlled Human Trials to Explore the Role of Inter‐Individual Variability

Abstract

Several epidemiological studies have linked flavonols with decreased risk of cardiovascular disease (CVD). However, some heterogeneity in the individual physiological responses to the consumption of these compounds has been identified. This meta-analysis aimed to study the effect of flavonol supplementation on biomarkers of CVD risk such as, blood lipids, blood pressure and plasma glucose, as well as factors affecting their inter-individual variability. Data from 18 human randomized controlled trials were pooled and the effect was estimated using fixed or random effects meta-analysis model and reported as difference in means (DM). Variability in the response of blood lipids to supplementation with flavonols was assessed by stratifying various population subgroups: age, sex, country, and health status. Results showed significant reductions in total cholesterol Subgroup analysis showed a more pronounced effect of flavonol intake in participants from Asian countries and in participants with diagnosed disease or dyslipidemia, compared to healthy and normal baseline values. In conclusion, flavonol consumption improved biomarkers of CVD risk, however, country of origin and health status may influence the effect of flavonol intake on blood lipid levels.

Meta-Analysis of the Effects of Foods and Derived Products Containing Ellagitannins and Anthocyanins on Cardiometabolic Biomarkers: Analysis of Factors Influencing Variability of the Individual Responses

“…We show, for first time, that the significant effects of ET-rich products on T-C, LDL, TAGS and DBP and of ANC-rich food products on T-C, DBP and SBP were consistently observed in participants with BMIs ≥ 25 kg/m 2 (overweight/obese). Similar results were found in a previous meta-analysis, looking at the effects of flavanol-containing products in T-C [29]. Together, these results suggest that supplementation with polyphenol-rich products may have a beneficial impact on some cardiometabolic risk factors in overweight and/or obese people.…”

“…There are important differences between studies for a number of key factors (body mass index (BMI), sex, smoking habits, diet, health status) that likely influence the response of the participants to the intake of the compounds tested. These differences can mask significant effects in specific populations [28,29]. …”

The urinary phenolic acid profile varies between younger and older adults after a polyphenol-rich meal despite limited differences in in vitro colonic catabolism

“…This varied from one participant excreting 8 out of 17 phenolic acids to another excreting 17 out of 17 phenolic acids. This is particularly relevant as inter-individual variability in the response to (poly)phenolics (including flavonols) is now being increasingly considered [61]. However, whether inter-individual variability of (poly)phenols metabolism suggests a biological difference between the age groups is still unclear.…”

Effect of meat product with onion skin extract on мetabolic profile in SHR

“…According to meta-analyses quercetin supplementation was associated with a positive effect on blood lipid profile. It was observed in small but significant decrease in total cholesterol, LDL cholesterol and triacylglycerol and significant increase in HDL cholesterol [5].…”

“…Quercetin protects blood vessels from the damaging effects of oxidative stress, especially from lipid peroxidation, decreases blood pressure, leads to lowering of LDL cholesterol and causes cardioprotective effect. Results from human randomized controlled trials showed that flavonol consumption, especially quercetin, improved biomarkers of CVD risk [5]. Dietary supplementation with quercetin significantly reduced systolic blood pressure in overweight subjects with a high CVD risk and decreased plasma oxidised LDL concentrations that reflects cardioprotective effect of flavonoid [6].…”