Nutraceutical effects of table green olives: a pilot study with Nocellara del Belice olives

Background: The aim of this study was to analyse the nutraceutical properties of table green olives Nocellara del Belice, a traditional Mediterranean food. The Mediterranean Diet has as key elements olives and extra virgin olive oil, common to all Mediterranean countries. Olive oil is the main source of fat and can modulate oxidative stress and inflammation, whereas little is known about the role of olives. Moreover, emerging evidences underline the association between gut microbiota and food as the basis of many phenomena that affect health and delay or avoid the onset of some age-related chronic diseases. Methods: In order to show if table green olives have nutraceutical properties and/or probiotic effect, we performed a nutritional intervention, administering to 25 healthy subjects (mean age 38,3), 12 table green olives/day for 30 days. We carried out anthropometric, biochemical, oxidative stress and cytokines analyses at the beginning of the study and at the end. Moreover, we also collected fecal samples to investigate about the possible variation of concentration of Lactobacilli, after the olives consumption. Result: Our results showed a significant variation of one molecule related to oxidative stress, malondialdehyde, confirming that Nocellara del Belice green olives could have an anti-oxidant effect. In addition, the level of interleukin-6 decreased significantly, demonstrating how this food could be able to modulate the inflammatory response. Moreover, it is noteworthy the reduction of fat mass with an increase of muscle mass, suggesting a possible effect on long time assumption of table olives on body mass variation. No statistically significant differences were observed in the amount of Lactobacilli, although a trend towards an increased concentration of them at the end of the intervention could be related to the nutraceutical effects of olives. Conclusion: These preliminary results suggest a possible nutraceutical effect of daily consumption of green table olives Nocellara del Belice. To best of our knowledge, this is the first study performed to assess nutraceutical properties of this food. Of course, it is necessary to verify the data in a larger sample of individuals to confirm their role as nutraceuticals.