Text Box: 8:50 AM Text Box: CHEMISTRY & NUTRITION Text Box: The effect of food matrix on soy metabolism and biomarkers of cardiac risk Text Box: Jennifer Ahn-Jarvis and Dr. Schwartz Text Box: Despite numerous decades of research, the benefits of soy isoflavone consumption evidenced in epidemiological and in vitro studies have not been validated in human investigations. The paucity of information and conflicting findings pertaining to soy bioavailability and its role in cardio-protection contribute to this lack of validation. This is compounded by differences in soy processing, consumption and inter-individual variations in dietary isoflavone metabolism/excretion have been implicated in affecting soy bioavailability. The specific aim of this study was to assess differences in isoflavone metabolism after consumption of two different soy food matrices (soy bread and soy beverage) and to examine the consequences of soy consumption on cardiovascular risk biomarkers (total cholesterol, high density lipoprotein, low density lipoprotein, triglycerides, c-reactive protein, antioxidant capacity, apolipoprotein A1 and apolipoprotein B). This study was a randomized, two-treatment, crossover design that included twenty (10 female and 10 male) adult (23-63 years old), hypercholesterolemic (200-275 mg/dL) subjects. Soy bread (three slices/day) consumption was assessed in one treatment while the other was a soy beverage (one package/day). Both products delivered 20 g soy protein and 100 mg total isoflavone (aglycone equivalents) daily. Blood and urine were collected for cardiovascular disease risk biomarkers and soy isoflavone analysis at the end of the washout (2-weeks) and treatment (3-weeks) periods. Differences were noted in metabolite excretion profiles between the two products but no significant differences were found in total isoflavone excretion nor in lipids. During the beverage treatment 17 subjects produced ODMA (O-desmethylangolensin) in comparison to 11 consuming bread. Moreover, 6-OH ODMA was excreted only by women (5) and predominantly during bread consumption. One subject produced equol with bread but not with beverage treatment. Change in apolipoprotein A1 was statistically significant (p=0.013) specifically with soy beverage treatment. These findings support the current working hypothesis that gender and food matrix affect soy metabolism and short term soy consumption can significantly change apolipoprotein A1 suggesting that soy interventions can