Participants who consumed 400g of oranges daily for four weeks showed beneficial trends towards lower glucose levels, higher levels of vitamins C and A, and changes in cholesterol markers.
“To our knowledge, this study adds clinical evidence on the metabolic effects of whole “Navelina” orange consumption in patients with MASLD, with particular interest in the potential contribution of its polyphenol content,” wrote researchers at the National Institute of Gastroenterology in Italy
Metabolic Dysfunction‐Associated Steatotic Liver Disease (MASLD), formerly known as non‐alcoholic fatty liver disease (NAFLD), is the most prevalent chronic liver disease worldwide, affecting around 25%–30% of the adult population. The disease is closely related to obesity, insulin resistance, type 2 diabetes, and dyslipidemia, with glucose and lipid metabolism a central feature.
Dietary management of MASLD includes limiting sugar intake, but the metabolic effects of sugar consumption may depend on the type of food. Previous research suggests that sugars from fresh fruit may have different metabolic effects from those of added sugars and sweetened drinks.
Citrus fruits contain vitamins, fiber, and bioflavonoids such as hesperidin that may have beneficial effects on glucose and lipid metabolism, potentially being helpful in MASLD.
Using fructosamine as a marker allows researchers to measure short-term changes in blood glucose and reflects glycemic exposure over approximately the preceding 2–3 weeks. The current study used fructosamine to assess glucose and lipid metabolism after consuming whole oranges rather than juice, because the polyphenol content is higher in whole oranges.
Study details
The Researchers randomly assigned 66 participants aged 30 to 65 with MASLD to either an experimental group that consumed 400 g/day of whole “Navelina” oranges (approximately 2-3 peeled oranges) for 4 weeks or a control group that didn’t consume the oranges.
They measured metabolic markers at the start and end of the study to evaluate changes in glucose and lipid parameters.
“Significant time–treatment interactions were observed for dietary sugars, vitamin A, and vitamin C,” they reported, noting that the increases in vitamins are consistent with the nutritional effects of oranges and should not be interpreted as clinically relevant.
No significant interactions were observed for fasting glucose, insulin, and the insulin markers HOMA-IR and QUICKI.
There was a non-significant trend towards reduced fructosamine levels in the experimental group; Fructosamine is a marker of short-term glycemic exposure. However, because fructosamine can be affected by albumin levels, which were not measured, the researchers recommended interpreting this result with caution.
“The observed exploratory associations between LDL and insulin-sensitivity markers warrant further investigation of the relationship between lipid and glucose metabolism in response to whole citrus fruit consumption,” they wrote.
The researchers recommended future long-term trials that adjust for albumin and investigate dose–response relationships.
Source: Nutrients 2026, 18(21), 3668; https://doi.org/10.3390/nu18213668, “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.” Authors: V. De Nunzio et al.
