The object of this work was to investigate the intake and distribution of conjugated linoleic acid (CLA) in plasmalipids to contribute to the explanation of the physiological meaning of the CLA-isomer C18:2 c9t11 in humans. The intake of a subgroup of the German National Food Consumption Survey varies from 92 mg/d to 1338 mg/d. The mean intake of the CLA-isomer C18:2 c9t11 was calculated to be 400 mg/d for women and 512 mg/d for men. The intake was normally distributed and between women and men significant different. The butter consumption contributed 40 % of the total intake of the CLA-isomer C18:2 c9t11, followed by the group "milk, milk products and cheese" (30 %), "sausages and meat goods" (20 %) and "meat and poultry" (10 %). A newly developed food frequency questionnaire (FFQ; long-term intake) was validated by a 7-day estimated record (7-d ER; medium-term intake). The difference between both assessment methods were statistically significant. The FFQ gives mean intake values 24 % lower than found with the 7-d ER. The results of the fatty acid analysis in plasma phopholipids (PL) and triglycerids (TG) demonstrates that the mean proportion of the CLA-isomer C18:2 c9t11 is twice as high in TG (0,54 % FAME) than in PL (0,27 % FAME). It was shown that the concentration of the CLA-isomer C18:2 c9t11 could be used as a biomarker for the short term intake, since a significant correlation with r = 0.41 resulted. The concentration in PL is a possible biomarker for the medium-term intake, because the intake correlates significant and acceptable (r = 0,29) with the concentration in the PL. The concentration in the PL correlates only poor and not significant with the long-term intake of the CLA-isomer C18:2 c9t11. The concentration of the CLA-isomer C18:2 c9t11 of 30 lunches was calculated by means of a database and compared with the results of analysis. The calculation of the CLA-isomer C18:2 c9t11 overrates the concentration in comparison to the analysis. The within-person variation of the CLA-isomer C18:2 c9t11 in plasmalipids was examined to determine whether the concentration in the plasmalipids is suitable as a biomarker. A high within-person variation of 40 % resulted in the PL and TG. This high variation coefficient can be explained by the measurement inaccuracy due to the small concentrations, and by the small study group of 6 persons. The absorption of the CLA-isomer C18:2 c9t11 from a CLA-supplement was examined with a dosis of 1,3 or 2,6 g/d. The concentration of the CLA-isomer C18:2 c9t11 in plasma TG were twice as high with the higher dosage compared to the smaller dosage. In case of a proportional view however, no difference resulted. The concentration of the CLA-isomer C18:2 c9t11 in the chylomicrones corresponded not to the concentration in the CLA-supplement but to the test meal. Finally, the habitual dietary intake is the substantial source of the CLA-isomer C18:2 c9t11 in humans. The concentration of the CLA-isomer C18:2 c9t11 in plasma PL and TG represents candidate biomarkers for the short-term and medium-term intake of the CLA-isomer C18:2 c9t11.     «

The object of this work was to investigate the intake and distribution of conjugated linoleic acid (CLA) in plasmalipids to contribute to the explanation of the physiological meaning of the CLA-isomer C18:2 c9t11 in humans. The intake of a subgroup of the German National Food Consumption Survey varies from 92 mg/d to 1338 mg/d. The mean intake of the CLA-isomer C18:2 c9t11 was calculated to be 400 mg/d for women and 512 mg/d for men. The intake was normally distributed and between women and men...     »