In my quest to the right chocolate dose recently discovered a letter in the BMJ about this subject. The authors did a meta analysis. Their results suggest that dark chocolate is superior to placebo in reducing blood pressures of more than 140 mm Hg systolic or more than 80 mm Hg diastolic.
Daily flavanol dosages ranged from 30 mg to 1 g (equivalent to 6.3 g to 100 g of milk or dark chocolate), and interventions ran for two to 18 weeks. Data were insufficient to provide confident answers on optimal dosage and time frame.
However, they question the practicability as a long term treatment. Can you imagine that? They found that 50 g daily of chocolate was significantly less acceptable to participants as a long term treatment for high blood pressure than one capsule daily of placebo or tomato extract (73% v 100%).
From a systematic review of 10 randomized clinical trials: chocolate has blood pressure lowering capacity. Dark chocolate has a high content of flavanols. Flavonoids are the part of chocolate important for health benefits. They can also be found in high concentrations in certain fruits and vegetables. In the context of human nutrition, certain teas, grape juice, wine, various berries, and especially cocoa represent noteworthy sources. Dark chocolate has the highest content of flavonoids compared to the other sources. Besides lowering the blood pressure chocolate containing flavonols also has other cardioprotective properties.
On average over all trials chocolate reduced blood pressure. Systolic blood pressure was reduced with 4.5 mmHg and diastolic blood pressure with 2.5 mmHg. Treatment duration of these 10 randomized clinical trials ranged from 2 to 18 weeks. Participants were either healthy without hypertension or patients with stage 1 hypertension. Definition of stage 1 hypertension:
A minimum blood pressure value of 140/90. Stage 1 Hypertension is an early form of high blood pressure, and may require treatment with medicine, the is why you should have a blood pressure monitor get one via their site www.bestsellers.bargains, in order to avoid progression to Stage 2 Hypertension.
Possible mechanism of action of the blood lowering effect of chocolate are:
increase in vasodilating nitric oxide bioavailability possibly caused, in part, by an enhanced nitric oxide synthase activity
the inhibition of angiotensin converting enzyme activity
The chocolate dosage varied widely across studies, so still no answer to the important question: How much chocolate a day keeps hypertension away?. Moreover, chocolate is high in calories, one of the side-effects could be weight gain which is another risk factor for hypertension and other cardiovascular diseases. Were looking for very flavanols rich dark chocolate in optimal dose.
Desch, S., Schmidt, J., Kobler, D., Sonnabend, M., Eitel, I., Sareban, M., Rahimi, K., Schuler, G., & Thiele, H. (2009). Effect of Cocoa Products on Blood Pressure: Systematic Review and Meta-Analysis American Journal of Hypertension, 23 (1), 97-103 DOI: 10.1038/ajh.2009.213
Dark chocolate reduces risks of cardiovascular disease by means of lowering systolic and diastolic blood pressure as well as increasing flow mediated dilatation after acute and chronic intake. Acute black tea consumption increased systolic and diastolic blood pressure. Green tea reduced LDL cholesterol. Soy protein isolate but not other soy products also reduces LDL cholesterol, but this is hard to mix with the green tea and dark chocolate. So for reduction of the risk for cardiovascular disease green tea with dark chocolate seems the best option.
These are the results of a meta analysis of randomized controlled trials. The authors included
One hundred thirty-three trials were included. No randomized controlled trial studied effects on CVD morbidity or mortality. Significant heterogeneity confirmed differential effects between flavonoid subclasses and foods.
They wanted to examine the relative importance of the different flavonoid subclasses and flavonoid-rich foods. But data were limited, study samples were mostly small, duration was mostly short, mostly with chocolate and soy no dose-response effects, and lack of clinically relevant endpoints.
Flow mediated dilatation
Because endothelial dysfunction is an integral component of atherosclerosis, and because in vitro evidence suggests that at least some flavonoids exert their effects via the endothelium, endothelial function [measured as flow-mediated dilatation (FMD)], which is a predictor of cardiovascular events and which correlates with other CVD risk factors.
high levels of LDL cholesterol can signal medical problems like cardiovascular disease, it is sometimes called “bad cholesterol” (as opposed to HDL, the “good cholesterol”).
Lee Hooper, Paul A Kroon, Eric B Rimm, Jeffrey S Cohn, Ian Harvey, Kathryn A Le Cornu, Jonathan J Ryder, Wendy L Hall, and Aedín Cassidy (2008). Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials The American Journalof Clinical Nutrition, 88 (12), 38-50 DOI: 18614722
In this recently published review we summarized the results of the placebo-controlled randomized clinical trials with beta-blocking adrenergic agents during electroconvulsive therapy (ECT), and review the effect on seizure duration and cardiovascular variables.
Esmolol can have a significant effect on seizure duration during ECT, it shortens seizure duration, and this effect is probably dose dependent.
Since the relation between seizure duration and efficacy of ECT is dependent on electrode placement it seems advisable to use bilateral electrode placement with patients with cardiovascular risk factors and use of esmolol during every session before seizure induction. One should take into account the possible negative effect of esmolol on seizure duration in these cases and adhere to the guidelines for ECT that advise at least 10 treatment sessions with bilateral ECT before one can conclude that ECT is not efficacious.
In the absence of cardiovascular risk factors but with prolonging hypertension or tachycardia during ECT sessions, esmolol also is again preferred. Labetalol is an alternative although, especially in high dose, the longer half-life can be considered as a disadvantage. Experiences with landiolol are limited but the short half-life, greater degree of cardioselectivity and more potency makes it a promising alternative.