South Asian individuals at high risk of type 2 diabetes have lower plasma vitamin C levels than white Europeans

Individuals of South Asian origin are at high risk of developing type 2 diabetes; the relationship between this risk and diet remains to be investigated fully. Furthermore, fruit and vegetable intake remains low throughout the world and previous data suggest that intake is associated with risk of diabetes. The aim of this research study was to compare plasma vitamin C concentrations, measured as a biomarker for fruit and vegetable intake, in South Asian and white European individuals. Participants recruited as part of the Let's Prevent Diabetes Study provided samples for the quantification of plasma vitamin C. We compared vitamin C levels by ethnicity using multiple regression, both unadjusted and adjusted for confounders, including glycaemic status. Mean plasma vitamin C was significantly lower in the South Asian participants compared with white European participants (34.5 (sd 19·8) v. 39·9 (sd 22·1) µmol/l, respectively; P ≤ 0·0001). Significantly fewer South Asian individuals consumed five portions of fruit and vegetables per d, as determined by a plasma vitamin C concentration of ≥ 50 µmol/l (23·2 % (n 58) v. 31·4 % (n 558); P = 0·01). Vitamin C reflects habitual fruit and vegetable consumption; thus results suggest that South Asians have lower fruit and vegetable intake. However, it cannot be excluded that vitamin C is utilised differently. Dietary advice specifically targeting the South Asian population should be developed.