Trans-unsaturated fatty acids in margarines and human subcutaneous fat in Israel

Representative Israeli dietary fats were analysed by capillary gas chromatography, with emphasis on the trans-fatty acid (FA) content. The percentages of trans-monoenes were relatively high: 28.5-30.4 in three hard margarines, 13.4 in both of two soft margarines, but 0 in both of two cooking oils and 27.6 for a sample of commercial cookies. The corresponding percentages of trans-dienes were 0.4-0.5, trace-0.9, 0-0.1 and 0 (one oil sample had 0.6 had 0.6 per cent trans-triene). For cis-polyunsaturated FA the percentages were 26.4-28.7, 39.7-41.6, 60.6 and 18.2 respectively. P/S ratios for the hard margarines were 1.69-2.01, higher than those of American margarines, which are about 1.40. When trans-FA were included with the saturated FA, the ratios were almost equal, 0.52-0.60 versus 0.53, respectively. In the subcutaneous fat of 8 Israelis of various ethnic origins and dietary habits, total trans-FA averaged 4.5 per cent (range 1.9-6.6), similar to that in the US and UK. However, the percentages of polyunsaturated FA in the Israelis were very high, 27.2 (20.3-32.3) for linoleic acid and 1.5 (1.0-1.8) for linolenic acid. The average P/S ratio was also very high, 1.19 (0.80-1.60) and P/(S+trans) was 0.98 (0.67-1.37).