Investigations on rapeseed oil toxicology

A series of investigations on humans and mice, performed in this laboratory in the years 1973-74 is presented. To assess the exposure levels of the Italian population to rapeseed oil ingestion, the serum of 70 apparently healthy railway workers, as well as the adipose tissue and myocardium of 16 subjects deceased for different causes were analyzed, with a gas chromatographic method, to ascertain if erucic acid or its metabolites were present. 40 out of 70 subjects had measurable erucic acid in the serum ranging from 0.3 to 3.8% of the total fatty acids (mean 1.1 +/- 0.14) in the presence or absence of behenic acid, probable metabolite of erucic acid in humans. Furthermore 26 subjects had measurable behenic acid alone. Each of the 16 subjects had measurable erucic acid in adipose tissue ranging from 0.3 to 6.8% of the total fatty acids (mean 2.6 +/- 0.5) always in the presence of gadoleic acid (present in rapeseed oil, product of beta-oxidation of erucic acid and only partially deriving from other sources) ranging from 1.1 to 4.9% (mean 2.2 +/- 0.3). 13 subjects out of 14 analyzed had measurable erucic acid in the myocardium ranging from 0.2 to 2.2% (mean 0.7 +/- 0.18) while 9 subjects had measurable gadoleic acid. Erucic acid was absent in the human tissues in Italy in the years 1967-68. Regarding the studies on mice, the deposition of erucic and gadoleic acids in some organs of young mice supplied with 50% of daily calories for three days in rapeseed oil was investigated. The deposition of the two fatty acids amounts to about 10% of the total fatty acids in the heart and liver and considerably less in skeletal muscle and kidney. In the mouse liver there is also a decrease in hexobarbital metabolism following rapeseed oil ingestion.