Ingestion of ALA-rich flaxseed oil or GLA-rich borage oil
led to increases in the contribution of the respective fatty
acid to total plasma lipids (Tables 2–4). Changes in other
fatty acids were not observed, apart from increases in
DGLA in the group supplemented with borage oil. DGLA is
likely formed from GLA by an elongase-catalysed twocarbon
chain elongation. In addition to elongases, desaturases
are required for the synthesis of arachidonic acid and higher
homologues of the n-6 family as well as for C20 PUFA of
the n-3 family. Increases of C20 PUFA in plasma and different
lipid fraction in the blood have been shown after application
of high doses of ALA(21). In the present study the total dose
of ALA and GLA was quite low and thus changes in the
levels of longer-chain fatty acids may have been too small
for detection. It should be further noted that the pattern of
plasma lipids does not necessarily reflect the lipid composition
of tissues such as skin. Some major effects observed here are
likely due to more significant changes in skin lipids. However,
dermal punch biopsy would be required to analyse the fatty
acid pattern at the target site