Monday, July 09, 2007


The 4th July issue of JAMA, carried an interesting piece of work by Dr Dick Taubert et al of Cologne, Germany, on the effects of a small piece of dark chocolate a day, for 18 weeks, on Blood Pressure. There have been 5 previously well documented studies on the effects of dark chocolate on blood pressure. This one is perhaps the most elaborate, and also giving us some hints to the mechanism involved.

They studied 44 adults with pre-hypertension (people whose BP is borderline), aged 56-73 yrs. They conducted a randomised controlled trial. One half received one piece of dark chocolate (6.3 gms, 30 kcals) daily and the other arm the equivalent amount of polyphenol free, white chocolate. After 18 weeks they found that the dark chocolate arm had a significant reduction of their systolic and diastolic BP, with also a reduction in BP prevalance in this group of pre-hypertensives.

They also showed that this came with no additional BMI, blood lipids or blood sugars. This benefit is likely to be the result of an increase in production of nitric oxide on the endothelium causing better vaso-dilation and so better endothelial function - thereby lowering BP. Implied in this statement is that better endothelial function must translate to less atherosclerosis.

With six good studies showing this outcome, the impression is strong. The sad thing is we all know that we need a large randomised control trial to prove this to us, but an RCT is hard to come by as pharmas with the big bucks are unlikely to come forward to sponsor because they cannot write a patent on dark chocolates (I think). So although we should all take a small piece a day of dark chocolate (6.3 gms) daily, we would not be able to give a class 1 evidence. I think that I shall surely try this. Hypertension, with the possibility of stokes, is a dreaded disease. If I can prevent this, I will and I must.

1 comment:

V said...

I agree that a RCT is not possible unless the NIH or MRC fund these studies. I am not sure but does commercially sold dark choclate contain salt?