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Diet rich in flavonoids could provide health benefits for people with Type 2 diabetes

A diet rich in foods containing powerful antioxidants called flavonoids may not only lower the risk of heart disease in women with Type 2 diabetes but also reduce their cholesterol and help manage diabetes, suggests a new study by the University of East Anglia.

Published today in the journal Diabetes Care, the Diabetes UK funded 12-month trial provides further evidence that diet offers extra protection in people at high risk of cardiovascular complications.

Reduced risk of heart attack

Ninety-three postmenopausal women with Type 2 diabetes took part in the trial. Half were given two small bars of flavonoid-enriched chocolate each day, and half were given placebo chocolate bars. Those receiving the extra flavonoids reduced their risk of suffering a heart attack in the next decade by 3.4 per cent. Their insulin resistance and cholesterol levels were also significantly reduced.

Commercial chocolate of little benefit

However, the researchers emphasise that the results do not mean that people with Type 2 diabetes should eat more chocolate. This is because commercially available chocolate contains much less of the beneficial flavonoids than the chocolate consumed in the trial, and eating too much chocolate may cause weight gain.

Flavonoids protect the cells in your body from damage by free radicals, which are molecules produced by pollution and the body’s normal metabolic processes, and which are responsible for causing ageing, tissue damage and possibly some diseases. Foods such as onions, apples, berries, kale and broccoli contain the highest concentrations of flavonoids; high amounts are also found in tea, dark chocolate and even red wine. The chocolate bars used in the trial were specially created with the help of a Belgian chocolatier to provide a high dose of two types of flavonoids.

Postmenopausal women with diabetes were chosen for the study because, despite being on established statin therapy, they are at high risk of heart disease. Deaths due to heart disease increase rapidly after menopause, and having Type 2 diabetes increases this risk by a further three-and-a-half times.

Better protection than conventional drugs?

Dr Iain Frame, director of research at Diabetes UK, said, “Although this trial involved quite a small number of women already at high risk of heart disease, these compounds appeared to offer them better protection against heart problems than conventional drugs when administered under very carefully controlled circumstances.

“Flavonoids are found in tea, red wine and other foods, but this study only looked at the effects of specially prepared chocolate with much higher amounts of flavonoids than in chocolate available commercially. We would be very concerned if the results of this research were reported as encouraging people with Type 2 diabetes to increase their consumption of chocolate and red wine. Both of these can cause weight gain that would eliminate the health benefits described here and should only be consumed as part of a healthy balanced diet. It will be interesting to see whether larger studies of different flavonoids in more diverse populations over longer periods demonstrate similar effects.”

Previous studies have shown that dietary flavonoids reduce the risk factors for heart disease in healthy people. However, this is the first long-term study to examine their effect on a medicated, high-risk group.

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