Insulin resistance and adiposity in relation to serum β-carotene levels.

Objective To determine the effects of placebo vs an encapsulated supplement of fruit and vegetable juice concentrate (FVJC) on serum beta-carotene levels, insulin resistance, adiposity, and subclinical inflammation in boys. Study design Thirty age-matched prepubertal boys (9 lean and 21 overweight (OW); age range, 6-10 years) were studied. All participants received nutrition counseling and were randomized to receive FVJC or placebo capsules for 6 months. Total cholesterol, triglycerides, lipid corrected beta-carotene, serum retinol, glucose, insulin, retinol binding protein-4, leptin, adiponectin, leptin-to-adiponectin ratio, high-sensitivity C-reactive protein, and interleukin-6 were measured before and after the 6-month intervention. Homeostasis model assessment-insulin resistance (HOMAIR), acute insulin response to intravenous glucose, along with abdominal fat mass (dual-energy x-ray absorptiometry) were also determined. Results Baseline beta-carotene concentrations correlated inversely with HOMA-IR, leptin-to-adiponectin ratio, and abdominal fat mass (P <= .01). FVJC intake increased beta-carotene concentrations (P <= .001) but did not influence retinol or retinol binding protein-4. Retinol insufficiency <1.047 mu M was present in 18% of the entire cohort at baseline and in 37% at 6 months. HOMA-IR decreased after supplementation in the OW cohort, when adjusted for percent weight change (P = .014). The percent change in abdominal fat mass increased in the placebo group and decreased in the FVJC group (P = .029). Conclusions A 6-month supplementation with FVJC in the presence of nutritional counseling was associated with an increase in serum beta-carotene concentrations and a reduction in adiposity in conjunction with an improvement in insulin resistance in OW boys. (J Pediatr 2012; 161: 58-64).