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Geppert, Julia (2007): Evaluation of two supplementation strategies to improve long-chain omega-3 fatty acid status in healthy subjects. Dissertation, LMU München: Faculty of Medicine
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Abstract

This work was intended to evaluate two supplementation strategies to improve long-chain omega-3 fatty acid (n-3 LCPUFA) status in healthy adults. Two randomised, double blind, placebo-controlled intervention studies with parallel design were performed. The first study investigated the effects of a docosahexaenoic acid (DHA)-rich, almost eicosapentaenoic acid (EPA)-free microalgae oil (Ulkenia sp.) on red blood cell (RBC) and plasma fatty acids, plasma lipids and several safety parameters. Normolipidaemic vegetarians (87 f, 27 m) consumed daily microalgae oil (0.94 g DHA/d) or olive oil (as placebo) for 8 wk. DHA supplementation significantly increased DHA levels in RBC total lipids (from 4.4 to 7.9 wt%, means), in RBC phosphatidylethanolamine (from 6.5 to 12.1 wt%), in RBC phosphatidylcholine (from 1.4 to 3.8 wt%), and in plasma phospholipids (from 2.8 to 7.4 wt%). EPA levels rose to a much lesser extent. Microalgae oil provided for an increase in omega-3 index (from 4.8 to 8.4 wt%); after intervention, 69% of DHA supplemented subjects, but no subject of the placebo group reached an omega-3 index with a desirable value > 8 wt%. DHA supplementation decreased plasma triacylglycerol (TG) by 23% from 1.08 to 0.83 mmol/l. Plasma total, LDL and HDL cholesterol increased significantly in the DHA group, resulting in a lower TG:HDL cholesterol ratio and unchanged LDL:HDL and total cholesterol:HDL cholesterol ratios. The intake of DHA-rich microalgae oil did not result in any physiologically relevant changes of safety and haemostatic factors. In conclusion, DHA-rich oil from microalgae Ulkenia sp. was well tolerated and can be considered a suitable vegetarian source of n-3 LCPUFA. Although DHA supplementation improved some cardiovascular risk factors (plasma TG, TG:HDL cholesterol ratio), LDL cholesterol increased. Therefore, the overall effects of this intervention on cardiovascular risk deserve further investigation. The second study investigated the effects of a fish oil / evening primrose oil (FO/EPO) blend (456 mg DHA/day and 353 mg gamma-linolenic acid (GLA)/day) compared to a placebo (mixture of habitual dietary fatty acids) on the plasma fatty acid (FA) composition in two groups of 20 non-pregnant women. FA were quantified in plasma total lipids, phospholipids, cholesterol esters, and TG at weeks 0, 4, 6 and 8. After 8 weeks of intervention, percentage changes from baseline values of plasma total lipid FA were significantly different between FO/EPO and placebo for GLA (+49.9% vs. +2.1%, means), dihomo-gamma-linolenic acid (DGLA, +13.8% vs. +0.7%) and DHA (+59.6% vs. +5.5%), while there was no significant difference for arachidonic acid (ARA, -2.2% vs. -5.9%). FA changes were largely comparable between plasma lipid fractions. As compared to placebo, FO/EPO supplementation did not result in any physiologically relevant changes of safety parameters (blood cell count, liver enzymes). In conclusion, in women of childbearing age the tested FO/EPO blend is well tolerated and appears safe. It increases plasma GLA, DGLA, and DHA levels without impairing ARA status. These data provide a basis for testing this FO/EPO blend in pregnant women for its effects on maternal and neonatal FA status and infant development.