Polyunsaturated Fatty Acids of Blood Serum and the Assessment of their Ratios in Clinically Healthy Adults Living in the Arctic Territories of Russia

Abstract

Background: The study of the content of polyunsaturated fatty acids (PUFAs) in permanent residents of the Arctic territories, characterized by high activity of lipid metabolism, is of undoubted interest. The aim of this study was to assess the composition of omega-3 and omega-6 PUFAs in blood serum by gas-liquid chromatography and individual PUFA ratios in clinically healthy adults living in the Russian Arctic and Sub-Arctic regions. Materials and Methods: A total of 1,556 healthy adult residents (the age groups of 22-35, 36-45 and 46-60 years) of the northern territories were examined. Of these, 661 people were living in the Sub-Arctic region (SAR) and 895 people in the Arctic region (AR). Analysis of PUFA composition in blood serum was determined by gas-liquid chromatography after transesterification to volatile fatty acid methyl esters (FAME). We determined the content of ω-3 PUIFAs: α-linolenic acid (ALA), eicosatrienoic acid (ETE), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA); and ω-6 PUFAs: dihomo-γ-linolenic acid (DGLA), linoleic acid (LA), arachidonic acid (AA), docosatetraenoic acid with the common name adrenic acid (AdA). Results: In the clinically healthy individuals born and permanently living in SAR and AR, there was an age-related increase in LA level combined with an increase in the levels of AA, AdA and DGLA, as well as an increase in ALA level combined with an increase in the levels of EPA, DPA and DHA, the content of which was higher in AR individuals. In all age groups of adult residents of SAR, an increase in the AA/EPA ratio and a decrease in the EPA/DPA and (DGLA EPA)/DHA values were observed relative to similar age groups of AR, which indicates disorders in the PUFA metabolism and intensification of pro-inflammatory eicosanoid synthesis. In AR, a statistically significant increase in both ω-3 and ω-6 PUFAs can be a compensatory-adaptive reaction aimed at preserving the lipid component of cell membranes and reducing the risk of their destruction. An increase in the AA/DGLA ratio can be considered as a hidden risk criterion for the synthesis of pro-inflammatory eicosanoids.

Keywords

• ω-3 and ω-3 polyunsaturated fatty acids
• adults
• arctic and sub-arctic regions