Flavanol-Containing Cocoa Helps Blood Vessel Disease

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Sustained benefits in vascular function through flavanol-containing cocoa in medicated diabetic patients, by Jan Balzer and colleagues. Journal of the American College of Cardiology 51:2141—2149, 2008

What is the problem and what is known about it so far?

Diet is a major lifestyle factor that can influence the development and progression of chronic diseases, including diabetes. Recently, studies have suggested that flavanols, a type of chemical found in fruit, vegetables, tea, red wine, and especially cocoa, may have a beneficial effect on heart and blood vessel disease, diabetes, and related conditions.

Why did researchers do this particular study?

The researchers wanted to find out if boosting flavanols in the daily diet can improve blood vessel function in patients with type 2 diabetes.

Who was studied?

The study included 41 adult subjects with established and stably treated type 2 diabetes for at least 5 years.

How was the study done?

First, 10 subjects were asked to refrain from eating other foods rich in flavanols and were given a single cocoa drink containing one of three different doses of flavanol-containing cocoa. They were then tested for their blood vessel function and their digestion and tolerance of the flavanols. Next, all 41 subjects received either flavanol-containing cocoa or another substance that was nutritionally similar but did not contain large amounts of flavanols three times a day for 30 days. They were not asked to change their usual eating habits. Their blood vessel functioning was then tested and compared.

What did the researchers find?

For the single-dose study, greater sizes of flavanol dose resulted in better blood vessel functioning. For the 30-day study, blood vessel functioning was improved by 30 percent from initial levels in those receiving flavanols, and the treatment was well-tolerated and had no negative effects on other metabolic processes. The degree of improvement in blood vessel functioning was comparable to improvements shown in previous studies using exercise; assorted medicines including statins, ACE-inhibitors, and pioglitazone; and insulin.

What were the limitations of the study?

The study design did not allow researchers to learn exactly how flavanols improve blood vessel flow. Also, the study involved a small number of participants and a short period of time.

What are the implications of the study?

Diets rich in flavanols can improve blood vessel problems in people with diabetes and may be useful in helping to prevent or delay progression of heart and blood vessel disease.

FOR MORE INFORMATION

Diabetes and heart and blood vessel disease

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