Effect of the Moro and Pera orange juice intake on gut microbiota composition in obese individuals

Background:
Citrus juices contain greater quantities of bioactive compounds as flavones, flavonols, anthocyanins, and flavanones. The blood oranges are a pigmented sweet orange and the most common types of blood orange are varieties Moro, Tarocco, and Sanguinello. In recent years, there was an increase of interest in blood orange varieties because of their higher content of anthocyanins compared with non-pigmented variants (Pera, Navel, Valencia, and Ovale). Many studies have been described blood orange juice, especially variety Moro with antioxidant, antimutagenic, and anti-obesity properties. These are all bioactive compounds in juice and it is health benefits may be mediated by the synergic effects of its compounds. In the last years, the effect of these bioactive compounds, especially anthocyanins has been described in some studies indicating that the consumption of foods high in anthocyanins promotes the growth of certain types of beneficial bacteria and inhibits pathogenic bacteria. It has been demonstrated that obese individuals have a disrupted gut microbiota, with less diversity and richness than lean subjects. This altered gut microbiota is related to the metabolic disorders contributing to the development of type 2 diabetes, metabolic syndrome,
cardiovascular diseases, and certain cancers. Thus, the consumption of food rich in bioactive compounds can confer positive health benefits in obese individuals by modulation on gut microbiota composition.

Objective:
The objective of this study was to evaluate the effect of orange juice intake and the order of treatment in the modulation of gut microbiota of obese individuals with insulin resistance.

Methods:
A crossover clinical trial was conducted with 22 adults between 40 and 60 years old classified as obese according to BMI and insulin resistance by HOMA-IR. The volunteers were divided into two study groups where Group A was composed of 15 people and Group B was composed of 7. In the beginning of the the study group A consumed pera orange juice (POJ) and group B started with the moro orange juice (MOJ), for 15 days they consumed 400ml per day. In a second 40-day intervention (crossover), study-group subjects were switched to the opposite drinking order. The microbiome was analyzed based on new generation sequencing techniques of 16S rRNA genes. For data analysis, volunteers were categorized according to the order of treatment (who started with MOJ and those with POJ). This categorization was made considering the hypothesis that intake of anthocyanins before or after ingesting flavanones could have different effects and it could interfere with the composition of intestinal microbiota.

Statistical analysis:
Data are expressed as means ± SEM. The data were analyzed using a Mann- Whitney t-test for comparison between two groups. A value of P < 0.05 was considered statistically significant.

Results:
There was a significant difference between groups A and B. This difference can be explained by the phenolic compounds found in both juice types associated with synergistic effects that are dependents on the order of the treatment. Group B showed a higher abundance relative of
Ruminoccocaceae, Lachnospiraceae, and Erysipelotrichaceae, however, these were not classified when compared to group A. This suggests that phenolic compounds found on MOJ could directly stimulate the growth of a specific bacteria. The Ruminoccocaceae and Lachnospiraceae families have been linked to the production of short-chain fat acid, an important energy source for colonic epithelial. In addition, the Lachnospiraceae family has been associated with improved insulin resistance, lipid metabolism, reduction of body weight, and antioxidant effects. Erysipelotrichaceae, as well as Lachnospiraceae family, were associated with inflammation reduction and improved insulin sensitivity in mice.

Conclusions:
In conclusion, our results suggest that MOJ followed by POJ intake may improve the dysbiosis associated with obesity through the stimulus of bacterial growth – especially the bacteria that (a) metabolize bioactive compounds and (b) enhance the synthesis of beneficial metabolic
products protecting gut homeostasis.