Cocoa for blood pressure, with and without exercise.
Article Type: Report
Subject: Hypertension (Care and treatment)
Cocoa (Usage)
Cocoa (Health aspects)
Blood pressure (Measurement)
Blood pressure (Methods)
Exercise (Physiological aspects)
Exercise (Research)
Author: Hunter, Kim
Pub Date: 06/22/2010
Publication: Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2010 National Herbalists Association of Australia ISSN: 1033-8330
Issue: Date: Summer, 2010 Source Volume: 22 Source Issue: 2
Topic: Event Code: 310 Science & research
Product: Product Code: 2066860 Powdered Cocoa NAICS Code: 31132 Chocolate and Confectionery Manufacturing from Cacao Beans SIC Code: 2066 Chocolate and cocoa products
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 232178437
Full Text: Davidson K, Berry NM et al. 2010. Dose-related effects offlavanolrich cocoa on blood pressure. J Hum Hypertension Jan 21 (Epub ahead of print).

This study from researchers at the University of South Australia and the University of Adelaide shows that regular consumption of cocoa flavanols may decrease blood pressure in people with mild hypertension, but only at high doses.

Consumption of flavanol containing cocoa products has been shown to lower blood pressure (BP), but the minimum dose required to reduce BP was not known. This study examined the effect of three different doses of cocoa flavanols (CF) on 24 hour mean arterial BP. Twenty four hour ambulatory BP (24-ABP) monitoring was performed in 32 men and 20 postmenopausal women with untreated mild hypertension (seated clinic BP >130/85 and <160/100 mm Hg). Participants were randomised and instructed to consume a reconstituted cocoa beverage containing 33, 372, 712 or 1052 mg of CF daily for 6 weeks in a double blind parallel comparison. Seated clinic BP and 24-ABP were measured at 0, 3 and 6 weeks.

Seated clinic BP did not change during the study period. There were significant reductions in 24-h systolic (5.3+/-5.1 mm Hg; p=0.001), diastolic (3+/-3.2 mm Hg; p=0.002) and mean arterial BP (3.8+/-3.2 mm Hg; p=0.0004) at the 1052 mg CF only. No reduction in BP was seen at any other dose. No evidence of dose response was seen in this experiment. The highest dose of 1052 mg CF per day was found to significantly lower BP. These results support previous evidence for CF to lower BP, however more research is needed to establish the most effective dose and food matrix

These findings suggest that blood pressure can be lowered through the regular consumption of flavanol rich cocoa beverages, although higher levels of cocoa flavanols may be required than has been observed with consumption of chocolate based cocoa flavanol rich products.

Berry NM, Davidson K et al. 2010. Impact of cocoa flavanol consumption on blood pressure responsiveness to exercise. Brit J Nutr 103:10;1480-4.

This study completed by some of the same University of South Australia researchers as the cocoa study above, investigated whether consumption of cocoa flavanols, which improve endothelium dependent flow mediated dilatation (FMD), can modify blood pressure (BP) responsiveness to exercise.

Impaired endothelial vasodilatation may contribute to the exaggerated BP responses to exercise in individuals who are overweight/obese. This study included twenty one volunteers (13 male, 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). Participants 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 day washout between treatments. Two hours after cocoa consumption FMD was measured followed by continuous beat to beat assessment of BP before and during 10 mins of cycling at 75%%o of age predicted maximum heart rate.

Results showed that pre exercise BP was similar after taking LF and HF cocoa. However the BP response to exercise was attenuated by HF compared with LF. BP increases were 68% lower for DBP and 14% lower for mean BP. FMD measurements were higher after taking HF than after taking LF. 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. While again results were limited to high flavanol cocoa, interestingly these results were achieved with a lower flavanol dose than the previous study.

Kim Hunter mnhaa
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