Evaluating whole fruit feijoa powder for type 2 diabetes risk prevention: the FERDINAND study

BackgroundLow energy diets (LEDs) are effective for body weight (BW) loss and improvement of type 2 diabetes (T2D) risk biomarkers. Emerging evidence suggests that whole fruit feijoa powder, rich in polyphenols and abscisic acid, may further support T2D prevention. The FERDINAND study investigated whether daily consumption of a whole fruit feijoa powder enhanced LED-driven improvements in fasting plasma glucose (FPG), BW, and other metabolic markers during a 6-month intervention in adults with overweight and prediabetes. MethodsAt in-clinic screening 97 participants were enrolled into the trial and randomised to receive 1.15 g/day of whole fruit feijoa powder (Feiolix(R), Fx, n=48) or Placebo treatment (n=49) for 6 months. All participants underwent 2-months of LED-induced weight loss, followed by 4 months of dietary advice for weight loss maintenance. FPG, BW and secondary outcomes including blood pressure (BP) and body composition, were assessed at 0 (baseline), 2 (post-LED), 4 and 6 months (end of study). Data was analysed using linear mixed-effects models as both raw/observed data (OD) and intention-to-treat (ITT) with imputation for missing not-at-random data points. Extreme outliers were removed prior to analyses. Statistical significance was set to P[&le;]0.05. ResultsBW significantly decreased in both treatments during the 2 month LED, with rebound towards baseline by 6 months (time0-6m: P<0.001), but with no difference between Fx and Placebo groups over the full intervention (treatmentxtime0-6m, ns). FPG followed the weight loss trajectory and also decreased and rebounded in both treatment groups (time0-6m: P<0.001), but the interaction between time and treatment over 6 months was significant (ITT: treatmentxtime0-6m, P=0.05). At month 2 FPG was lower than baseline in both treatments, but at month 6 only Fx treatment remained significantly lower than baseline (P<0.05) and was also lower than Placebo (P<0.05). In some participants, FPG reverted to normal or worsened to T2D between enrolment and baseline assessment. When excluded, the sub-group with confirmed prediabetes showed similar outcomes for pattern of change in trajectory for Fx vs. Placebo treatment (ITT: treatmentxtime0-6m, P=0.04) but with no significant difference between the two treatments at study end. Systolic BP (SBP), but not diastolic BP, also changed significantly over 6 months between treatments (treatmentxtime0-6m, OD: P=0.009, ITT: P=0.01), with SBP lower in Fx compared to Placebo at all timepoints (P<0.05). However, no difference between treatments was apparent in the sub-group of participants confirmed as normotensive at baseline (treatmentxtime, ns). ConclusionsIn adults with overweight and prediabetes, Fx supplementation may enhance improvements in glycaemia and blood pressure achieved through weight loss. The findings should be interpreted with some caution, given the influence in FERDINAND of individuals with FPG and blood pressure outside prediabetic and normotensive ranges. Nevertheless, these results warrant further investigation in larger cohorts at risk of T2D to fully evaluate the contribution that whole fruit feijoa powder can make to improved metabolic health.