Compounds in orange help control blood sugar, study suggests

A study carried out at the University of São Paulo (USP) suggests that bioactive compounds found in oranges help to modulate blood sugar levels, which can turn the fruit into an ally in the fight against diabetes. The findings were reported in the journal Clinical Nutrition Espen.

The investigation was conducted by a team from the Food Research Center of the University of São Paulo (FoRC), a Research, Innovation and Diffusion Center (CEPID) of Fapesp based at the Faculty of Pharmaceutical Sciences (FCF-USP).

Participants were 12 healthy volunteers, of both sexes, who, after an overnight fast, ingested a meal rich in fat and carbohydrates, with 1,037 kcal. They were divided into three groups: one that drank only water during the meal, another that had orange juice and a third that received a glucose-based drink with a carbohydrate content equivalent to that of orange juice.

The blood glucose level of the volunteers was analyzed one, three and five hours after the end of breakfast. In the first measurement, as expected, the three groups showed an increase in blood glucose. Interestingly, the blood glucose (blood glucose level) and insulinemia (blood insulin rate) values ​​of the orange juice group did not differ significantly from those observed in the water group at all assessments.

“If the intake of orange juice does not differ from the intake of water, we can conclude that the carbohydrates in the juice did not promote a significant increase in blood glucose in our experimental model, unlike what happened with the glucose-based drink”, explains Bruna Jardim Quintanilha , PhD student in nutrition at the Faculty of Public Health (FSP-USP) and first author of the article.

According to Quintanilha, this result suggests that other components present in the juice, such as fibers and bioactive compounds, may have contributed to contain the increase in the glycemic rate.

The next step was to investigate how orange juice would have helped to contain the increase in blood glucose. For this, the scientists collected blood samples from the volunteers and analyzed the expression of the so-called microRNAs, a type of RNA that has the function of regulating the expression of genes through interactions with messenger RNA.

“We noticed that orange juice had a particular action on microRNA 375 or miR-375, which is a biomarker of the function of pancreatic beta cells”, explains Franco Lajolo, professor emeritus at FCF-USP and member of the FoRC.

As the researcher explains, beta cells are very numerous in the organ and are responsible for synthesizing and secreting insulin – a hormone that allows glucose to enter the cells.

The results therefore indicate that orange juice may have a beneficial action on insulin production and, consequently, on glycemic modulation.

“Our results point to miR-375 as a possible responsible for this action, but it is something that still needs to be confirmed. Studies with diabetic patients are needed, for example, to understand exactly how this mechanism works”, says Lajolo.