Page 16 - Nutrinsight-3

NutrInsight • Do we need dietary polyphenols for health?
Taking into account the different parameters measured during this trial, they found that the estimated 10-year total coronary heart disease risk (derived from UK Prospective Diabetes Study algorithm) was slightly lowered in the flavonoid group (-1.04 % in flavonoid versus placebo group).
• Flavonoid-rich foods and cardiometabolic risk factors
A meta-analysis of 133 RCTs published up until June 2007 (some acute and some chronic) was performed to review the effectiveness of flavonoids and flavonoids-rich foods on cardiovascular disease risk [Hooper et al., 2008]. Of these trials most of them assessed the effect of flavanols. Interventions have shown that cocoa/chocolate (8 studies) significantly improved endothelial function measured as FMD and reduced blood pressure, and that cocoa/chocolate, soy/soy protein isolates (39 studies) and green tea (4 studies) decreased plasma LDL (a beneficial effect on lipid profile). However, in some cases it was not clear that the beneficial effects could be ascribed to the polyphenols contained in these foods or extracts. For many of the other flavonoids, there was insufficient evidence to draw conclusions about efficacy and dose necessary to reach a significant effect. The optimal dose of specific flavonoids for cardiovascular protection needs further research.
• Flavanol-rich cocoa and CVD
The ingestion of flavanol-rich cocoa beverage containing 917 mg of total flavanols in healthy male adults was associated with acute elevations in levels of circulating NO species, an enhanced FMD response of conduit arteries, and an augmented microcirculation [Schroeter et al., 2006]. In addition, the concentrations and the chemical profiles of circulating flavanol metabolites were determined, and multivariate regression analyses
Risk of hypertension
identified (-)-epicatechin and its metabolite, epicatechin-7-O-glucuronide, as independent predictors of the
vascular effects after flavanol-rich cocoa ingestion (Figure 7).
A12 B4 10 *# 3
8*# *# 2 6 *# 1
*#
#
C3,500 3,000 2,500 2,000 1,500
hFCD IFCD
*#
*#
0123456 0123456 0123456 Time after cocoa drink (h)
*#
*#
1,000 *# 2 -1**500
40
*#
* *** 0 -2 0
Figure 7: Changes in FMD and NO metabolites following high flavanol cocoa drink
Ingestion of a high flavanol cocoa drink (hFCD, 917mg of total flavanols) exerted significant increases in FMD (A), plasma NO metabolites (RXNO) (B), and circulating flavanols (C) compared with a low-flavanol control drink (lFCD, 37 mg). *, P < 0.05 vs. baseline at 0 h of respective day; #, P < 0.05 vs. respective time point on control day.
Source: Schroeter et al., 2006
In another study [Heiss et al., 2007], 306 mg total flavanols were consumed thrice daily. A day-on-day increase in brachial artery FMD was shown which is important because of the transient nature of the FMD effect.
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Flow-mediated dilation (%)
Increase RXNO (nM)
Sum of plasma flavanols (nM)