Changes in human plasma essential fatty acid levels as a result of administration of linoleic acid and gamma-linolenic acid.

Administration of doses of linoleic acid (LA) up to 36 g/d in humans raised blood levels of linoleic acid but not of its metabolites. This is probably because the conversion of LA to gamma-linolenic acid (GLA) is slow and rate-limiting. We have found that administration of relatively small amounts of GLA, up to 360 mg/d, raises human blood levels of dihomogammalinolenic acid (DGLA) and arachidonic acid (AA).