Effects of Whole “Navelina” Orange Consumption on Glucose Homeostasis and Fructosamine Levels in Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): A Randomized Controlled Trial

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely linked to insulin resistance and altered glucose and lipid metabolism. Fructosamine assays can provide complementary information regarding short-term glycemic exposure, making them particularly useful in the context of short-term nutritional interventions. This study evaluated the effects of whole “Navelina” orange consumption on glucose homeostasis in patients with MASLD. Methods: Sixty patients with MASLD were randomly assigned to an experimental or control arm. The experimental arm consumed 400 g/day of whole “Navelina” oranges for 4 weeks, while controls abstained from orange consumption. Fasting glucose, insulin, fructosamine, HOMA-IR, and QUICKI were assessed at baseline and follow-up. Generalized estimating equation models evaluated time-by-treatment interactions. Exploratory Spearman correlations assessed associations between changes in the lipid and glucose-related parameters. Results: Significant time–treatment interactions were observed for dietary sugars, vitamin A, and vitamin C. No significant interactions were observed for fasting glucose, insulin, HOMA-IR, or QUICKI. Fructosamine levels showed a non-significant trend toward a reduction (p = 0.078). In the experimental arm, changes in LDL levels were positively correlated with HOMA-IR and insulin levels, and inversely correlated with QUICKI. Conclusions: This study is one of the first clinical trials to evaluate the potential impact of whole orange consumption on glucose metabolism. However, these exploratory findings require confirmation through randomized studies conducted on larger samples and over longer periods.