Effect of β-cryptoxanthin (β-Cx), Plant Sterols and Galactooligosaccharides on Systemic and Gastrointestinal Markers

Overview

Regular consumption of a beverage containing β-cryptoxanthin (β-Cx) and plant sterols (PS) has been shown to exert a synergic effect in reducing some markers of cardiovascular risk and bone-remodeling (formation and resorption). The present project aims to: * Evaluate (by in vivo and in vitro studies) the bioavailability of added β-Cx, PS and galactooligosaccharides (GOS) and its stability in the beverage employed in the proposed study. * Study the biological effect (bioefficacy) associated with the regular consumption of modified milk-based fruit beverages containing β-Cx, PS and GOS in post-menopausal women (target group) by assessing changes in inflammation, cardiovascular and bone turnover biochemical markers. * Characterize genetic variability (polymorphisms), genetic expression and DNA oxidative damage in the target group as determinants of bioavailability and biological effects of β-Cx, PS and GOS. * Evaluate the potential prebiotic effect associated to regular consumption of a beverage supplemented with β-Cx, PS and GOS: including "in vitro" studies and characterization of subjects' microbiota and possible microbiota changes associated to the beverage consumption.

A previous Clinical Trial (AGL2012-39503-C02) evidenced the beneficial synergic effects upon bone remodeling and cardiovascular risk of a beverage, based on juice and milk, and enriched with PS and β-Cx. "In vitro" and "in vivo" (clinical) studies have confirmed low absorption of PS and β-Cx in this beverage, with possible slight modification of the sterols and metabolites by the intestinal microbiota. PS and β-Cx can reach the colon and be transformed by the intestinal microbiota with resulting beneficial effects. The new Clinical Trial aims to determine whether the presence of galactooligosaccharides (GOS) in a beverage containing PS and β-Cx might modulate the biological effects of these latter components at either intestinal level (modification of microbiota and inflammatory markers) or systemically (blood cholesterol-lowering effect and bone turnover). In the present clinical interventional study we will evaluate the systemic biological effects of a beverage containing GOS, PS and β-Cx, as well as its intestinal effects and its influence on the microbiota in postmenopausal women. Furthermore, we will study the stability and bioavailability of PS and β-Cx in the beverage. The clinical study will help to confirm whether the new GOS-containing beverage has effects upon cardiovascular risk markers, bone remodeling and inflammation at least equivalent to those observed with the beverage studied in the previous Clinical Trial. The results obtained will generate interesting information for improving beverage formulation with bioactive components that might be relevant for food industry. Furthermore, clarifying the beneficial effects of the studied beverages is relevant not only for healthy subjects but also for those with certain disease conditions (i.e., intestinal inflammation diseases), and may contribute to improve their wellbeing and health, with the consequent social and economic benefits. DESIGN OF THE CLINICAL STUDY: Single and combined randomized, double-blind, crossover multiple-dose supplementation trial will be carried out with two beverages (250 ml/day): PS-enriched skimmed milk based fruit beverage rich in β-Cx (sham beverage) and a similar skimmed milk based fruit beverage rich in PS and β-Cx supplemented with GOS (active beverage),as diet supplementation in healthy post-menopausal women. The Clinical study will take place at the Vitamins Unit of the Clinical Biochemistry Service of the Hospital Universitario Puerta de Hierro-Majadahonda (Madrid, Spain). Sample size assessment: The sample size was calculated taking into account the results of total PS and cholesterol obtained in a previous clinical trial (no. NCT01074723). From previous assumption we choose the more conservative option to assure detection of a 7% reduction of cholesterol levels in a mild hypercholesterolemic subjects (e.g. 15 mg/dl) with a type I error of 0.05 and a statistical power of 80%. Furthermore, taking into account that 45% of western population might presented some polymorphisms implicated in the cholesterol absorption process, and assuming a drop-out of 10%, the final sample size should included 40 subjects. Standard Operating procedures: Two periods of intervention of 6 weeks separated by a wash-out period of 4 weeks. During the first trial period, 20 subjects daily will consume the active beverage and 20 subjects will consume the sham beverage for 6 weeks, and after a what-out period of 4 weeks, the type of beverage to be consume during other 6 weeks period will be change (two-by-two cross over assignment). All participants receive sham beverage and active beverage B at some point during the trial but in a different order, depending on the group to which they are assigned. Sample collection (serum and faeces) will be performed before and after each 6 weeks treatment periods. All subjects should give written consent to participate in the trial. The participants will be provided with a list of foods and beverage rich in β-Cx to be avoided during the trial period and will be asked not to change its usual diet and physical activity, to record any side effects during the study, and to complete a semi-quantitative Food Frequency Questionnaire (FFQ) at the end of each intervention period. Question on the organoleptic properties of the beverages will also be included.