Omega-3 Polyunsaturated Fatty Acid Status Testing in Humans: A Narrative Review of Commercially Available Options.

There is an increasing body of evidence supporting a link between low intakes of omega-3 long chain polyunsaturated fatty acids (LCPUFA) and numerous diseases and health conditions. However, few people are achieving the levels of fish/seafood or eicosapentaenoic acid and docosahexaenoic acid intake recommended in national and international guidelines. Knowledge of a person's omega-3 LCPUFA status will benefit the interpretation of research results and could be expected to lead to an increased effort to increase intake. Dietary intake survey methods are often used as a surrogate for measuring omega-3 PUFA tissue status and its impact on health and functional outcomes. However, since individuals vary widely in their ability to digest and absorb omega-3 PUFA, analytical testing of biological samples is desirable to accurately evaluate omega-3 PUFA status. Adipose tissue is the reference biospecimen for measuring tissue fatty acids, but less invasive methods, such as measurements in whole blood or its components (e.g., plasma, serum, red blood cell membranes) or breast milk are often used. Numerous commercial laboratories provide fatty acid testing of blood and breast milk samples by different methods and present their results in a variety of reports such as a full fatty acid profile, omega-3 and omega-6 fatty acid profiles, fatty acid ratios, as well as the Omega-3 Index, the Holman Omega-3 Test, OmegaScore™, and OmegaCheck®, among others. This narrative review provides information about the different ways to measure omega-3 LCPUFA status (including both dietary assessments and selected commercially available analytical tests of blood and breast milk samples) and discusses evidence linking increased omega-3 LCPUFA intake or status to improved health, focusing on cardiovascular, neurological, pregnancy, and eye health, in support of recommendations to increase omega-3 LCPUFA intake and testing.