CONTRIBUTION OF TRANS-18/1 ACIDS FROM DAIRY FAT TO EUROPEAN DIETS

Twelve commercial samples of French butter, purchased in October-November, and 12 other samples, purchased in May-June, were analyzed with particular attention to their trans-octadecenoic acid contents. The isomeric fatty acids mere quantitated by a combination of gas-liquid chromatography (GLC) of total fatty acids as isopropyl esters on a polar capillary column (CPSil 88) and of silver nitrate impregnated thin layer chromatography followed by GLC of the pooled saturated (used as internal standards) and trans-octadecenoic acid fractions. Autumn butters contained 3.22 +/- 0.44% trans-octadecenoic acids (relative to total fatty acids), whereas those collected during the spring contained 4.28 +/- 0.47% (P < 0.01). Minimum and maximum values for the two sets of butters were 2.46 (autumn) and 5.10% (spring), respectively. The annual mean value for the trans-octadecenoic acid content in all butter samples was 3.8% of total fatty acids (ca. 2% for the trans ll 18:1 acid). This value allows calculation of the daily in individual intake of trans-octadecenoic acids from dairy products by populations of member states of the European Economic Community (EEC). It varies from 0.57 g (Portugal) to 1.66 g (Denmark). The mean value for the twelve countries of the EEC is 1.16 g/person/d, which is close to data published for the United States. In France, the consumption of trans octadecenoic acids from dairy fat is higher than that from margarines (ca. 1.5 vs. 1.1 g/person/d).