RESEARCH NEWS: Cocoa Flavanols May Decrease Risk of Cardiovascular Disease

An Australian study has found that cardiovascular disease risk may be affected by cocoa flavanols. The randomized, double-blind, crossover design study involved 21 subjects (eight females and 13 males) with an average age of 54.9 years old. Study participants were given a single serving of either a high-flavanol (701mg) or low flavanol (22mg) cocoa beverage, and after two hours, measurements of flow-mediated dilation (FMD) and blood pressure (BP) were taken before and during 10 minutes of exercise. After exercise, BP increases in the high-flavanol group were significantly reduced, and FMD was also higher in this group. According to the authors of the study, “By facilitating vasodilation and attenuating exercise-induced increases in BP, cocoa flavanols may decrease cardiovascular risk and enhance cardiovascular benefits of moderate intensity exercise in at-risk individuals.”

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Article Abstract:

Br J Nutr. 2010 Jan 19:1-5. [Epub ahead of print]
Impact of cocoa flavanol consumption on blood pressure responsiveness to exercise.

Berry NM, Davison K, Coates AM, Buckley JD, Howe PR.

School of Health Sciences, Nutritional Physiology Research Centre and ATN Centre for Metabolic Fitness, University of South Australia, GPO Box 2471, Adelaide, SA 5001, Australia.

Impaired endothelial vasodilatation may contribute to the exaggerated blood pressure (BP) responses to exercise in individuals who are overweight/obese. The present study investigated whether consumption of cocoa flavanols, which improve endothelium-dependent flow-mediated dilatation (FMD), can modify BP responsiveness to exercise. Twenty-one volunteers (eight females and thirteen males, 54.9 (se 2.2) years, BMI 31.6 (se 0.8) kg/m2, systolic BP 134 (se 2) mmHg, diastolic BP (DBP) 87 (se 2) mmHg) were randomised to consume single servings of either a high-flavanol (HF, 701 mg) or a low-flavanol (LF, 22 mg) cocoa beverage in a double-blind, cross-over design with 3-7-d washout between treatments. Two hours after cocoa consumption, FMD was measured, followed by continuous beat-to-beat assessment (Finapres) of BP before and during 10 min of cycling at 75 % of age-predicted maximum heart rate. Averaged data from two assessments on each type of beverage were compared by analysis of covariance using pre-exercise BP as the covariate. Pre-exercise BP was similar after taking LF and HF (153 (se 3)/88 (se 3) v. 153 (se 4)/87 (se 2) mmHg, respectively, P>0.05). However, the BP response to exercise (area under BP curve) was attenuated by HF compared with LF. BP increases were 68 % lower for DBP (P = 0.03) and 14 % lower for mean BP (P = 0.05). FMD measurements were higher after taking HF than after taking LF (6.1 (se 0.6) % v. 3.4 (se 0.5) %, P < 0.001). By facilitating vasodilation and attenuating exercise-induced increases in BP, cocoa flavanols may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at-risk individuals.

SOURCE: Br J Nutr. 2010 Jan 19:1-5.