Chocolate Lowers Blood Pressure in High-risk Patients

Study examines the relationship between consuming chocolate and blood pressure levels in high-risk patients.

By Jacob Schor, ND, FABNO

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Reference

Desch S, Kobler D, Schmidt J, et al. Low vs. higher-dose dark chocolate and blood pressure in cardiovascular high-risk patients. Am J Hypertens. 2010 Mar 4. [Epub ahead of print]
 

Design

Prospective, randomized, open-label, blinded, end-point design trial.
 

Participants

102 patients with prehypertension/stage 1 hypertension and established cardiovascular end-organ damage or diabetes mellitus.
 

Study Medication and Dosage

Patients were randomly assigned to receive either 6 or 25 grams/day of flavanol-rich dark chocolate for 3 months.
 

Main Outcome Measures

The difference in 24-hour mean blood pressure between groups.
 

Key Findings

Both groups, those consuming either 6 or 25 grams/day of chocolate, had statistically significant reductions in mean ambulatory 24-hour blood pressure (6 grams/day: -2.3 mm Hg, 95% CI: -4.1 to -0.4; 25 grams/day: -1.9 mm Hg, 95% CI: -3.6 to -0.2). There were no significant differences in blood pressure changes between the 2 groups.
 

Practice Implications

This is just one of a series of recent papers suggesting that chocolate may have cardioprotective effects. Part of the theory to explain this effect is that the flavanols present in chocolate trigger nitric oxide synthases that increase nitric oxide production in the blood. Nitric oxide is a potent vasodilator and improves endothelial function. The authors of this clinical trial had previously published a meta-analysis of earlier studies of the impact of high-flavanol chocolates on blood pressure. Analyzing data combined from 10 trials comprising 294 individuals, they had calculated a mean decrease of -4.5 mm Hg (95% CI: -5.9 to -3.2; P<0.001) for systolic blood pressure and -2.5 mm Hg (95% CI: -3.9 to -1.2; P<0.001) for diastolic blood pressure.1 The actual mechanisms underlying the benefits are likely more complex.
 
The flavanols in chocolate also exert anti-inflammatory effects. In a study of 42 people at high risk for atherosclerosis who consumed 40 grams of cocoa powder per day for 4 weeks, significant reductions were measured in the expression of VLA-4, CD40, and CD36 in monocytes. Serum levels of the endothelium-derived adhesion molecules P-selectin and intercellular adhesion molecule-1 were also significantly lower.2
 
A 2008 study gave 28 healthy individuals daily chocolate doses to provide 700 mg of flavonoids/day. After one week, low-density lipoprotein fell by 6% and high-density lipoprotein rose by 9%.
Eating the chocolate reduced highly sensitive C-reactive protein levels in women.
Eating the chocolate reduced highly sensitive C-reactive protein levels in women.3
 
We soon may have one more tool in our bag for helping patients reduce elevated blood pressure. The above paper was unable to demonstrate a dose-dependent difference in effect between consumption of 6 grams and 25 grams per day; we do not have the wanted scientific justification to tell patients, “With chocolate, more is better.” Rather it appears that this particular benefit plateaus at a low dose. This may be advantageous as higher doses may cause unwanted weight gain.
 
Note: The chocolates used in this study are not currently sold over-the-counter in the United States.

About the Author

Jacob Schor ND, FABNO, is a graduate of National College of Naturopathic Medicine, Portland, Oregon, and now practices in Denver, Colorado. He served as president to the Colorado Association of Naturopathic Physicians and is on the board of directors of the Oncology Association of Naturopathic Physicians. He is recognized as a fellow by the American Board of Naturopathic Oncology. He serves on the editorial board for the International Journal of Naturopathic Medicine, Naturopathic Doctor News and Review (NDNR), and Integrative Medicine: A Clinician's Journal. In 2008, he was awarded the Vis Award by the American Association of Naturopathic Physicians. His writing appears regularly in NDNR, the Townsend Letter, and Natural Medicine Journal, where he is the Abstracts & Commentary editor.

References

1. Desch S, Schmidt J, Kobler D, et al. Effect of cocoa products on blood pressure: systematic review and meta-analysis. Am J Hypertens. 2010;23(1):97-103.
2. Monagas M, Khan N, Andres-Lacueva C, et al. Effect of cocoa powder on the modulation of inflammatory biomarkers in patients at high risk of cardiovascular disease. Am J Clin Nutr. 2009;90(5):1144-1150.
3. Hamed MS, Gambert S, Bliden KP, et al. Dark chocolate effect on platelet activity, C-reactive protein, and lipid profile: a pilot study. South Med J. 2008;101(12):1203-1208.


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