Evaluating Whole Fruit Feijoa Powder for Type 2 Diabetes Risk Prevention: A Randomised Controlled Trial

Low 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.

At in-clinic screening, 97 participants were enrolled into the trial and randomised to receive 1150 mg/day of whole fruit feijoa powder (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. BW, FPG, and secondary outcomes including blood pressure (BP) were assessed at baseline (M0) and the end of months 2 (M2), 4 (M4), and 6 (M6). Data were analysed using linear mixed-effects models as intention-to-treat (ITT) with imputation for missing not-at-random data points.

BW decreased in both treatment groups during the 2-month LED, with a gradual upward trajectory over the subsequent 4 months (time_0-6m: p < 0.001). There was no difference in BW between Fx and Placebo over the 6-month intervention (treatment×time_0-6m: p = 0.74). FPG followed the weight loss trajectory in both treatment groups (time_0-6m: p < 0.001), but with no between-group interaction over 6 months (treatment×time_0-6m: p = 0.09, n = 97). Systolic BP (SBP), but not diastolic BP, declined over the 6 months between treatments (treatment×time_0-6m: p = 0.01) in all participants, with SBP in Fx lower than Placebo at M4 and M6 (p < 0.05, both).

In adults with overweight (predominantly obesity) and prediabetes, Fx supplementation may enhance blood pressure improvement achieved through BW loss. The polyphenolic matrix of whole fruit feijoa, which contains a high proportion of catechins, may have contributed to vascular benefits.