Omega-3 fatty acids
nâˆ’3 fatty acids (popularly referred to as Ï‰âˆ’3 fatty acids or omega-3 fatty acids) are a family of unsaturated fatty acids that have in common a final carbonâ€“carbon double bond in the nâˆ’3 position (the third bond from the methyl end of the fatty acid).
Important nutritionally essential nâˆ’3 fatty acids include Î±-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), all of which are polyunsaturated. The human body cannot synthesize nâˆ’3 fatty acids de novo, but it can form 20-carbon unsaturated nâˆ’3 fatty acids (like EPA) and 22-carbon unsaturated nâˆ’3 fatty acids (like DHA) from the eighteen-carbon nâˆ’3 fatty acid Î±-linolenic acid. These conversions occur competitively with nâˆ’6 fatty acids, which are essential closely related chemical analogues that are derived from linoleic acid. Both the nâˆ’3 Î±-linolenic acid and nâˆ’6 linoleic acid are essential nutrients which must be obtained from food. Synthesis of the longer nâˆ’3 fatty acids from linolenic acid within the body is competitively slowed by the nâˆ’6 analogues. Thus accumulation of long-chain nâˆ’3 fatty acids in tissues is more effective when they are obtained directly from food or when competing amounts of nâˆ’6 analogs do not greatly exceed the amounts of nâˆ’3.
Research has shown that long-chain omega-3 fatty acids, primarily found in fish and seafood, may have a role in colorectal cancer prevention (See: http://oncozine.ning.com/profiles/blogs/omega3-fatty-acids-may-reduce )