Vitamin C-rich diet may slash diabetes risk

August 07, 2008

     Increased blood levels of vitamin C may reduce the risk of developing diabetes by 62 % says a new study from Cambridge University. The study followed 21,831 men and women for 12 years (they had an average age of 58.4 years). It also found a weaker association between fruit and vegetable intake and a reduced diabetes risk, supporting the importance of the five-a-day regime. “The strong independent association observed in this prospective study, together with biological plausibility, provides persuasive evidence of a beneficial effect of vitamin C and fruit and vegetable intake on diabetes risk,” wrote lead author Anne-Helen Harding from Addenbrooke’s Hospital in Cambridge, England.
     Correlating blood levels of vitamin C and diabetes, the researchers found that men and women with the highest blood levels had a 62 % reduction in their risk of developing type-2 diabetes, compared to men and women with the lowest blood levels.
     Moreover, men and women with the highest fruit and vegetable intake (459 and 550 grams per day, respectively) had a 22 % reduction in their risk of developing type-2 diabetes, compared to men and women with the lowest fruit and vegetable intake (289 and 382 grams per day, respectively).
     “Higher plasma vitamin C level and, to a lesser degree, fruit and vegetable intake were associated with a substantially decreased risk of diabetes,” wrote the researchers. “Our findings highlight a potentially important public health message in the benefits of a diet rich in fruit and vegetables for the prevention of diabetes.”
     Interestingly it was the type of fibre from food that impacted reducing diabetes risk according to the researchers “The lack of association of fruit and vegetable fibre with diabetes risk but the protective effect of cereal fibre for diabetes risk reported in a recent meta-analysis is noteworthy and may suggest that it is not the fibre content of fruit and vegetables per se that contributed to the reduced risk for diabetes in our study,” wrote the researchers. Turning their attention to other compounds in fruit and vegetables, the researchers noted the presence of vitamins, minerals, and phytochemicals that possess antioxidant activity. “Oxidative stress, the situation in which an imbalance between the levels of reactive oxygen species and antioxidants exists, can lead to disturbed glucose metabolism and hyperglycaemia,” they said. The study is published in the current issue of the journal Archives of Internal Medicine, Volume 168, Number 14, Pages 1493-1499