There is some epidemiological evidence that fruit juice consumption may be associated with an increased risk of developing type 2 diabetes( Reference Bazzano, Li, Joshipura and Hu 1 ), possibly due to an increased dietary glycaemic load, or a greater intake of fructose. However, citrus polyphenols have been shown to improve endothelial function and reduce inflammatory markers in patients with metabolic syndrome( Reference Rizza, Muniyappa, Iantorno, Kim, Chen and Pullikotil 2 ), effects which would oppose the development of insulin resistance.
This study aimed to assess the effect of drinking orange juice daily on insulin resistance, in an ‘at-risk’ female cohort, using a randomised, parallel group design.
Thirty two overweight women (20–45 yrs, 27–35 kg/m2), with mild fasting insulin resistance (HOMA-IR>1.5) were recruited from the community. A hyperinsulinaemic (60 mIU/m2), euglycaemic clamp was conducted before and after consuming 250 ml/day of either orange juice (Group A), or an orange flavoured drink (Group B) for 12 wks. Drinks were matched for energy and sugar (sucrose, glucose and fructose) composition. Blood pressure was measured after resting semi-supine for 5 min using automated oscillometry, and arterialised-venous blood samples were taken, before the start of the clamp, from a dorsal hand vein heated in air temperature of 50–55°C. Total body composition and regional analysis of Android (abdominal) and Gynoid (femoral-gluteal) fat distribution, were assessed using Dual Energy X-Ray Absorptiometry. Normally distributed data are presented as the mean (±STD) and non-parametric data are presented as the median (inter-quartile range).
Groups were matched at visit 1 with respect to all parameters, although there was a trend for systolic BP to be higher in Group B (p=0.063). No parameters changed significantly over time, within groups, although there was a trend for TNF-α to fall in Group A (p=0.027). No differences were observed between groups after the 12 wk intervention.
Daily consumption of 250 ml of orange juice, for 3 months, did not adversely affect insulin sensitivity, body composition, or other indices of the metabolic syndrome.
