April 2/Preventive Medicine Week -- According to a study from the U.S., "The long-chain omega-3 (n -3) fatty acids derived from fish, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with a reduced risk of cardiovascular disease and other chronic diseases. Study of the associations between EPA and DHA intake and disease requires a valid biomarker of dietary intake; however, the direct measurement of tissue fatty acid concentrations is expensive and time consuming."
"Because the nitrogen stable isotope ratio (N-15/N-14, expressed as delta N-15) is elevated in fish, we investigated whether delta N-15 is a valid alternative biomarker of EPA and DHA intake. We examined the relation between red blood cell (RBC) delta N-15 and RBC EPA and DHA in a community-based sample of 496 Yup'ik Eskimos with widely varying intake of n -3 fatty acids. We also assessed the correlation between delta N-15 and dietary EPA and DHA intake based on 24-hour dietary recalls and 3-day food records completed by a subset of 221 participants. RBC delta N-15 was strongly correlated with RBC EPA and DHA (r = 0.83 and 0.75, respectively). These correlations differed only modestly by sex and age class. RBC delta N-15 also correlated with dietary EPA and DHA intake (r = 0.47 and 0.46, respectively) and did not differ by sex and age. The results strongly support the validity of RBC delta N-15 as a biomarker of EPA and DHA intake. Because the analysis of RBC delta N-15 is rapid and inexpensive, this method could facilitate wide-scale assessment of EPA and DHA intake in clinical and epidemiologic studies," wrote D.M. Obrien and colleagues, University of Alaska.