Bioavailability of Citrus Flavanones and Their Effect on Cardiovascular Health Biomarkers

Consumption of flavanones has been associated with a reduction in risk of developing CVD, however flavanone bioavailability varies greatly in the population. The thesis aim was to investigate variations in absorption, as assessed by urinary excretion and, for the first time, the effect of commercially-available citrus supplements on CVD risk biomarkers. In study 1, 15 participants consumed orange juice (OJ; 500 ml: 8 mg naringenin, 42 mg hesperidin/100 ml) and/or soya-nuts (25g): 30 mg daidzein, 57 mg genistein/100 g). Urine was collected at 0, 0-4, 4-8, 8-12, 12-24 and 24-36 hr on each of three separate occasions; saliva was collected hourly (0-8 and 24 hr) after co-ingestion of OJ and soya-nuts. Daidzein was excreted to a greater extent than genistein (27-28% of dose ingested compared to 16-19%), whilst naringenin was excreted to a greater extent than hesperetin (9% vs 2.5-3%). There was a strong positive correlation between excretion of daidzein and genistein (r=0.72, p<0.01), and for hesperetin and naringenin (r=0.72, p< 0.01). Moreover, the amount of naringenin, and daidzein or genistein were correlated when co-ingested (r=0.73, p