Project 462819

Young women have higher omega-3 polyunsaturated fatty acid (PUFA) status compared to men, particularly docosahexaenoic acid (DHA), and although this may be due to faster rates of DHA synthesis, this has not been directly determined. Higher DHA status in young women is thought to be a metabolic adaptation to provide this critical nutrient to the developing fetus and infant, however, higher DHA levels are also linked to lower rates of heart disease. Recently, we have developed a novel method in rodents for determining DHA synthesis rates that can be easily applied to humans. A preliminary study suggests that DHA synthesis rates in female rodents may indeed be faster than in males, and a recent clinical trial of ours suggests that a larger increase in DHA levels of young women following EPA supplementation is dependent on the presence of a specific genetic variant. In the current proposal, we will apply a novel application for compound-specific isotope analysis (CSIA) of individual that takes advantage of very small differences in the carbon-13 content within the food supply to track omega-3 PUFA metabolism. Therefore, the objectives of this proposal are to 1) determine DHA synthesis rates in humans using a novel application for CSIA to and 2) identify the mechanisms related to the higher DHA levels in young women compared to men. To achieve these objectives, we will first supplement young women and men with a 13C enriched ALA supplement with frequent blood collections to track changes in 13C content of DHA for determination of DHA synthesis rates. Second, we will recruit young women and men based on genetic profile to identify the role of genetics in contributing to sex-specific differences in DHA synthesis rates. By identifying sex and genetic-specific differences in DHA syntheses rates, the results of our study may lead to personalized omega-3 PUFA nutritional advice to improve EPA and/or DHA status in pregnant women or individuals at higher risk for heart disease.