Effects of orange juice enriched with probiotics and vitamin D3 on glucose metabolism in high-cardiometabolic risk individuals: secondary outcomes of a randomised controlled trial.

OBJECTIVES: This secondary analysis of a randomised controlled trial (RCT) compared the effects of 100% orange juice (OJ) enriched with probiotics and vitamin D3 on glucose metabolism to unfortified OJ in high-cardiometabolic risk individuals. METHODS: This 8-week double-blinded RCT included two groups consuming 250 mL daily: unfortified OJ (control) and OJ with vitamin D3 (2000 IU) and probiotics (Lacticaseibacillus rhamnosus GG and Lacticaseibacillus casei Shirota, 108 CFU/mL) (FunJuice). Participants were fitted with a continuous glucose monitoring (CGM) system for 14 days before and during the last 2 weeks of the intervention, and underwent an oral glucose tolerance test (OGTT) at baseline and 8 weeks. RESULTS: Fifty individuals (17 males, 34%; 48.7 years; body mass index = 32 kg/m2) completed the trial (control-n = 24; FunJuice-n = 26). Measures of OGTT, as well as most of the CGM-derived indices, remained comparable between groups (p > 0.05). From the pairwise comparisons: (a) FunJuice reduced the high blood glucose index [-0.06 (-0.1, -0.02), p = 0.010)]; (b) the control and FunJuice decreased the 24-h area under the curve for glucose [-9 (-14.5, -3.5), p = 0.002, and -8.9 (-14.2, -3.6), p = 0.002, respectively]; and (c) the control group increased 30-min glycemic responses [20 (5.6, 34.4), p = 0.007)], at 8 weeks compared to the baseline. CONCLUSIONS: Daily consumption of enriched OJ did not lead to significant changes in glucose metabolism compared to the unfortified OJ. However, the OJ intake, with or without fortification, may have favorable effects on glycemic fluctuations. This study was a part of FunJuice-T2EDK-01922, which was funded by the EU Regional Development Fund and Greek National Resources.