# Hydroxyryrosol-Rich Olive Extract for Plasma Cholesterol Control
## 4 Discussion
Moreover, olive polyphenols might have effect on the bile flow and secondarily promote lipid fecal excretion by increasing the biliary cholesterol and the bile acid concentrations [34]. Previous evidence has shown that diet is one of the most important contributors to the balance of both the gut microbiota and bile acid homeostasis [35]. In particular, population studies that demonstrate a higher consumption of fruits and vegetables with a high content in polyphenols are associated with the enhancement of the growth of the probiotic bacteria that actively interact with the bile acid metabolising activity [36]. In addition, to date, a number of polyphenols have been reported to exert bile acid sequestering activity [37; 38]. As intervention studies have showed that the pharmaceutical sequestering agents decrease the circulating LDL-C, reduce obesity, improve insulin sensitivity, and induce thermogenesis [39], it is likely that polyphenols too--as bile acid sequestering agents of a natural origin--have potential for the treatment of the metabolic disease. In addition to the LDL-C lowering effect, SelectSIEVE(r) OptiChol increases the plasma levels of HDL-C. It is well known that the increase of TC and particularly of LDL-C is positively associated with the risk of ASCVD, while higher values of HDL-C are inversely correlated with the risk of ASCVD [40; 41]. A large meta-analysis of four prospective studies (namely the Lipid Research Clinics Prevalence Mortality Follow-Up Study, the Multiple Risk Factor Intervention Trial (MRFIT), the Framingham Heart Study, and the Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT)) showed that every 1 mg/dL increase in the HDL-C was associated with a significant coronary heart disease (CHD) risk reduction by3% in women and 2% in men [42]. For this reason, the favorable change in the HDL-C after the supplementation with SelectSIEVE(r) OptiChol is clinically relevant and deserves consideration. In effect, a systematic review on this topic has recently provided evidence that polyphenol-rich olive oil favors the enhancement of the HDL-C through the promotion of the HDL cholesterol efflux capacity, which is HDL-C main antiatherogenic function [43]. Based on the published evidence, olive polyphenols increase the HDL size and improve the HDL oxidative status and composition (i.e., promote a greater HDL stability, which is reflected as a TG-poor core) [44]. In this regard, a randomized crossover clinical trial involving 200 healthy male volunteers has recently showed that a 15-week dietary supplementation with olive oil with high phenolic content is able to exert further benefits on the HDL-C serum levels and the oxidative damage compared to refined olive oil, and it has definitely provided additional evidence to recommend the use of virgin olive oil as a source of bioactive compounds that are able to promote the optimization of some CV risk factors, including the increase in the HDL-C [45]. As expected [26], following the dietary supplementation with SelectSIEVE(r) OptiChol, also FPG and SUA mildly but significantly improved. This is particularly interesting and lays further conceptual foundations for the use of this extract in the prevention and treatment of first-stage MetS, considering that high SUA levels predict the incidence of MetS in populations [46]. In the past, a number of studies focused on the importance of the insulin resistance for hyperuricemia, bringing as link a fructose intake excess [47; 48; 49]. To date, several polyphenols have been tested as SUA-lowering agents and have been recognized for their ability to reduce the SUA levels through the inhibition of xanthine oxidase and renal urate transporters [50; 51; 52]. Finally, the observed effect on BP following the dietary supplementation with SelectSIEVE(r) OptiChol also needs to be discussed.