Cocoa may improve artery health in diabetics

Cocoa is known to reduce blood pressure and improve endothelial function in non-diabetics. Now it looks as thought this benefit extends to diabetics. In a small, randomised trial, investigators showed that type 2 diabetics who drank a large mug of hot cocoa can reverse vascular dysfunction.

The secret is the flavonols that cocoa contains. This study clearly established improvements in vascular function in diabetics who regularly consumed flavonol-containing cocoa, which highlights the potential benefits of flavonol-containing diets in preventing cardiovascular events in diabetics.

The investigators performed two studies: a 10-patient feasibility study to determine the appropriate dosing, to assess safety and tolerability, and to measure the effect size of the intervention to calculate sample size of the efficacy study. In total, 44 patients with treated type 2 diabetes were enrolled in the randomised, double-blind, parallel-group efficacy study, with half allocated to the treatment arm of 321 mg of flavanols per dose three times daily. The control patients also received some flavanols, albeit a much smaller amount, about 25 mg per dose three times daily.

Baseline flow-mediated dilation (FMD) values were 3.3% in both the treatment and control arms at the start of the intervention. The daily consumption of flavanol-containing cocoa by patients in the treatment arm resulted in continual increases in FMD, increasing from 3.3% at baseline to 4.1% on day 8 and to 4.3% by study completion on day 30. The investigators note that the acute effects of drinking cocoa in the treatment arm, those recorded two hours after ingestion, were of a similar effect size at study entry, day 8, and day 30, suggesting that patients did not become desensitised to the effects of drinking cocoa.

On day 30, the investigators report that the composite maximum increase in FMD, a combination of the chronic and acute effects of cocoa ingestion, was 5.8%, suggesting "a reversal of endothelial dysfunction." This reversal in endothelial dysfunction with cocoa is comparable to intermediate- and long-term interventions using exercise and various medications, including insulin, pioglitazone, ACE inhibitors, and statins, write Balzer and colleagues.

The high-flavanol cocoa used in this study,which provides much more flavanol than the typical US dietary intake of 20 to 100 mg daily is not sold in the supermarket.