A new study published online in the European journal Diabetologia in November 2017 by French researchers has found that a diet containing higher levels of antioxidant-rich foods was associated with a reduction of risk of type-2 diabetes in middle-aged women.

The researchers said that recent evidence suggests that oxidative stress may contribute to the pathogenesis of type 2 diabetes, while regular consumption of a diet rich in fruit and vegetables, tea, walnuts and blueberries, containing a variety of compounds with antioxidant activity, may help to lower the risk of type 2 diabetes.

The study reported that women with higher antioxidant scores had a 27 per cent reduced risk of type-2 diabetes, compared to those with the lowest scores.

At the beginning of the study the participants completed a dietary questionnaire, which included information on more than 200 food items. This enabled researchers to assess the 'total dietary antioxidant capacity' for each participant. None of the women had diabetes before the study began.

Scientists analysed total antioxidant capacity in 64,223 women between 1993 and 2008 to see whether overall diet was associated with type 2 diabetes risk.

The 64,223 women (mean age 52 ± 7 years) were from the French E3N-European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, and 1751 women had validated type 2 diabetes during 15 years of follow-up.

When the associations between antioxidant score and diabetes risk was analysed, the risk was diminished with increased antioxidant consumption.

"This link persists after taking into account all the other principal diabetes risk factors: smoking, education level, hypertension, high cholesterol levels, family history of diabetes and, above all, body mass index, the most important factor," said lead author Dr Francesca Romana Mancini from the Inserm U1018, Centre for Research in Epidemiology and Population Health, University Paris-Saclay.

The foods and drink that contributed most to a higher dietary antioxidant score were fruits and vegetables, tea and red wine (in moderation), while coffee was excluded from the analysis because it has already been linked to reduced risk of type 2 diabetes.

The researchers concluded that their findings suggest that the total antioxidant capacity may play an important role in reducing the risk of type 2 diabetes in middle-aged women. More studies are warranted to better understand the biological mechanisms underlying this inverse association.

The study, conducted by a team of researchers from France was led by Professor Guy Fagherazzi and Dr Francesca Romana Mancini from the Inserm U1018, Centre for Research in Epidemiology and Population Health (CESP) ‘Health across Generations’ Team, University Paris-Saclay, University Paris-Sud, Gustave Roussy, Espace Maurice TubianaVillejuif Cedex, France.