A Systematic Review and Meta-Analysis of the Effects of Flavanol-Containing Tea, Cocoa and Apple Products on Body Composition and Blood Lipids: Exploring the Factors Responsible for Variability in Their Efficacy

Abstract

Several randomized controlled trials (RCTs) and meta-analyses support the benefits of flavanols on cardiometabolic health, but the factors affecting variability in the responses to these compounds have not been properly assessed. The objectives of this meta-analysis were to systematically collect the RCTs-based-evidence of the effects of flavanol-containing tea, cocoa and apple products on selected biomarkers of cardiometabolic risk and to explore the influence of various factors on the variability in the responses to the consumption of these products. A total of 120 RCTs were selected. Despite a high heterogeneity, the intake of the flavanol-containing products was associated using a random model with changes (reported as standardized difference in means (SDM)) in body mass index (−0.15, p < 0.001), waist circumference (−0.29, p < 0.001), total-cholesterol (−0.21, p < 0.001), LDL-cholesterol (−0.23, p < 0.001), and triacylglycerides (−0.11, p = 0.027), and with an increase of HDL-cholesterol (0.15, p = 0.005). Through subgroup analyses, we showed the influence of baseline-BMI, sex, source/form of administration, medication and country of investigation on some of the outcome measures and suggest that flavanols may be more effective in specific subgroups such as those with a BMI ≥ 25.0 kg/m2, non-medicated individuals or by specifically using tea products. This meta-analysis provides the first robust evidence of the effects induced by the consumption of flavanol-containing tea, cocoa and apple products on weight and lipid biomarkers and shows the influence of various factors that can affect their bioefficacy in humans. Of note, some of these effects are quantitatively comparable to those produced by drugs, life-style changes or other natural products. Further, RCTs in well-characterized populations are required to fully comprehend the factors affecting inter-individual responses to flavanol and thereby improve flavanols efficacy in the prevention of cardiometabolic disorders.

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

“…It is thus difficult to attribute the beneficial effects to a particular compound(s). In this regard, some studies have been conducted with polyphenol-rich berry products in comparison with nutrient-matched controls to try to associate the polyphenols intake with the response of the individuals [30]. Also, the association between the intake of ET-containing pomegranate products and the effects on cardiometabolic risk factors has been investigated with some evidence of a potential link between responses and specific ET-derived metabolites, but the effects of other constituents of these products have not been fully discarded [31,32].…”

Green Tea Quality Evaluation Based on Its Catechins and Metals Composition in Combination with Chemometric Analysis

“…Although the changes in lifestyle and diet are still considered as the most significant, many data suggest that increased dietary intake of antioxidants is a crucial factor in the prevention of NCDs [ 9 , 10 , 11 , 12 ]. Among many secondary metabolites of plant origin, polyphenols are the most abundant and nutritionally significant ones, possessing a wide spectrum of biological activities [ 13 ]. Because of the significant concentration of catechins (flavan-3-ols) and high daily intake (estimated at 120 mL/person/day), tea infusions are recently considered as the major sources of these chemicals for a general population [ 14 , 15 , 16 ].…”

Polyphenols in human nutrition: from thein vitroantioxidant capacity to the beneficial effects on cardiometabolic health and related inter-individual variability – an overview and perspective

“…The meta-analysis on flavanols also confirmed that they beneficially modulate several cardiometabolic risk factors, such as plasma lipids, BMI and waist circumference. However, higher efficacy was demonstrated in the participants with BMI ≥ 25 kg/m 2 and in non-medicated individuals, revealing the inter-individual variability (117) . Similarly, the beneficial effects of ellagitannins and anthocyanins on selected cardiometabolic risk factors were found to be more prominent in overweight and obese subjects (118) , and the effects of hydroxycinnamic acids may be greater in individuals at higher cardiometabolic risk (119) .…”