1185-P: Erythrocyte Eicosapentaenoic and Docosahexaenoic Acid Are Reliable Biomarkers of Dietary Intake in Women of African Ancestry: The Federal Women's Study

To formulate precision nutrition prescriptions, it is essential to understand the relationship between dietary assessment, ethnicity and cardiometabolic disease. Erythrocyte (RBC) fatty acid (FA) profiles reflect long-term dietary fat intake but have not been rigorously compared with short-term FA intake in women of African ancestry who have paradoxically low triglycerides with high fat intake. We compared the type of dietary fat consumed (proportion of total fat) using food records with fasting RBC FA (mol%) determined by gas chromatography in 130 female, healthy, federal employees without diabetes (12% African Immigrants (AI), 47% African Americans (AA), 41% White Americans (WA)); mean age 43+10 y and BMI 30 + 6 kg/m²). Diet quality and home prepared meals were similar across ethnicities. AI reported the lowest energy intake. Regardless of absolute energy intake, macronutrient distributions were similar. Fat intake differed by ethnicity; WA had the highest saturated FA (SFA) and lowest eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and omega-3 index (EPA + DHA), while AI and AA had similar SFA, EPA and DHA intake. AI women had the highest RBC DHA and omega-3 index. Associations between FA intake and RBC profiles were significant for DHA (r=0.3, p<0.01), EPA (r=0.2, p<0.05) and the omega-3 index (r=0.2, p<0.01). Overall, RBC EPA and DHA were reliable biomarkers of dietary intake in women of African ancestry, consistent with data in predominantly white populations. These findings support the combined use of food records and RBC profiles for comprehensive dietary assessments. As RBC SFA and monounsaturated FA reflect both endogenous and exogenous sources, the discrepancies between intake and RBC profiles could reflect ethnic variations in nutrient metabolism. To enable precision nutrition prescriptions, exploration of population-specific biomarkers in concert with dietary assessment is needed.