Evaluation of two supplementation strategies to improve long-chain omega-3 fatty acid status in healthy subjects

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.