Having a high level of vitamin C in your blood, consistent with that achieved by supplementation and eating a high fruit and vegetable diet, reduces your risk of diabetes by 62%. That's the conclusion of a study of more than 21,000 people over a 12-year period, published in the Archives of Internal Medicine.1
Those in the top fifth of plasma vitamin C were 62% less likely to develop diabetes, compared to those in the bottom fifth. The greater a person's vitamin C levels, the lesser was their risk. This relationship was much stronger than the relationship between their intake of fruit and vegetables - those in the top fifth reduced their diabetes risk by 22%.
The level of vitamin C needed to induce this risk reduction was above 1.1mg per decilitre (1.1mg/dL) of blood for men and 1.29mg/dL for women. Those who supplement 1 gram a day have, on average, a level of 1.62mg/dL, while those who take a basic multivitamin, usually containing 60 to 80mg of vitamin C, have a level of 0.94mg/dL, compared to non-supplementers, who average 0.66mg/dL.
The lead author Anne-Helen Harding from Addenbrooke's Hospital in Cambridge, said: "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."
The researchers state that vitamin C's antioxidant properties may be specifically protective against diabetes. "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 hyperglycemia. Oxidative stress is consistently observed in patients with diabetes, and the degree of oxidative stress tends to be greater in those with more diabetic complications."
The moral of this story is supplement vitamin C, eat vitamin C rich foods and eat lots of fruit and vegetables.
Did you know that out of oranges, strawberries, kiwi fruit, pepper and brocolli that per 100g brocolli contains the most vitamin C, followed by peppers, Kiwi fruit, strawberries and then oranges!