The polyunsaturated fatty acids' determinants

The human body is able to synthesize fatty acids, except from two essential polyunsaturated fatty acids (PUFAs) that must be obtained from foods or supplements: the omega-3 alpha-linolenic acid and the omega-6 linoleic acid. These essential PUFAs may further synthesize n-3- and omega-6 long-chain PUFAs (LCPUFAs). The conversion into omega-3- and omega-6 LCPUFAs is competitive, since the same enzymes (elongase and desaturases) are needed for both pathways, and the conversion is thought to be limited in humans. Since omega-3 LCPUFAs (eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) have several proposed beneficial health effects, especially to cardiovascular disease, these fatty acids are sometimes also referred to as essential. This has led to a focus towards an increased dietary intake of omega-3 LCPUFAs from marine sources and a subsequent decrease in omega-6/omega-3 PUFA-ratio. Compared with many other countries, dietary and supplemental intakes of omega-3 LCPUFAs are high in Norway.

Recent research, however, indicates that the synthesis of LCPUFAs might be influenced by other, previously unknown factors, including B-vitamins. Interestingly, smoking is associated with both lower levels of circulating B-vitamins and changes in fatty acid profile. Therefore, we would like to examine the association between smoking habits, vitamins and serum PUFAs. Our hypothesis is that the focus on high dietary intake and/or supplements of omega-3 LCPUFAs is more excessive than necessary (Eli Skeie).