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More Information about Lipid and Fatty Acid Characterization of Seafood
Background
In terms of human nutrition and health benefits, the unique contribution of seafood is found in the lipid fraction, primarily the long-chain omega-3 polyunsaturated fatty acids (PUFAs) mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Following studies by Bang and Dyerberg in the 1970s (Bang et al., 1980) suggesting that the inclusion of fatty fish in the human diet could have potential protective effect for coronary heart disease, numerous studies have been conducted ranging from those assessing clinical outcomes from the consumption of omega-3 fatty acids to those investigating the mechanisms responsible for these effects at the cellular and molecular levels. In the early 1980s, NOAA recognized the potential important connection between oceans and human health and, jointly with the National Institutes of Health, initiated the Biomedical Test Materials Program. This program supported a large number of studies by providing a variety of test materials derived from fish oils, of consistent composition and quality, to facilitate the comparison of results among studies. Based on results from these NOAA-supported studies and numerous other studies, considerable evidence has been accumulated associating human health benefits with the omega-3 PUFAs found in fish oil.
Although the mechanisms are not fully understood, there is general agreement that both omega-6 and omega-3 fatty acids play different, but significant, roles in human health and that a dietary balance of these fatty acids is a key factor. In recent years, vegetable oils, high in levels of omega-6 fatty acids, have contributed increasingly as a source of dietary fat for Western populations. Simopoulous (2002) suggested that the excessive amounts of omega-6 PUFAs, and the resulting very high omega-6⁄omega-3 ratio (~15:1) found in today’s Western diets promotes the pathogenesis of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune disease, while lower omega-6⁄omega-3 ratios have suppressive effects. The essentiality of DHA in normal development of the brain and retinas has been established (Salem et al., 1993). Low intake of omega-3 fatty acids has also been related to depression and suicide (De Vriese et al., 2004).
This project will survey fat content and fatty acid compositions of selected farmed and wild sources of fish and shrimp on the US market to document the levels of the omega-3 PUFAs, as well as other fatty acids contained in these products. Additionally, the project will determine fat content and fatty acid composition of fish and shrimp from controlled feeding experiments designed to explore the effects of diet on the lipid and fatty acid composition of farmed seafood products.
Literature Cited
Bang, H.O. and Dyerberg, J., 1980. Lipid metabolism and ischemic heart disease in Greenland Eskimos. In: Draper, H. (Ed.), Advances in Nutritional Research, vol. 3. Plenum Press, New York, pp. 1-22.
Christie, William W. 1989. Gas Chromatography and Lipids, A Practical Guide. The Oily Press, Ayr.
De Vriese, S.R., Christophe, A.B., Maes, M., 2004. In humans, the seasonal variation in poly-unsaturated fatty acids is related to the seasonal variation in violent suicide and serotonergic markers of violent suicide. Prostaglandins, Leukotrienes and Essential Fatty Acids 71, 13-18.
Joseph, J.D. and Seaborn, G.T., 1990. The analysis of marine fatty acids. In: Stansby, M.E. (Ed.), Fish Oils in Nutrition, Van Nostrand Reinhold, New York, pp. 40-72.
Salem, N., Jr., Wark, G.R., 1993. Are ω3 fatty acids essential nutrients for mammals? World Review of Nutrition and Dietetics 72, 128-147.
Simopoulos, A.P., 2002. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine & Pharmacotherapy 56, 365-379.