trans Octadecenoic acid and trans octadecadienoic acid are inversely related to long-chain polyunsaturates in human milk: results of a large birth cohort study.

BACKGROUND

Several observational studies indicate that trans isomeric fatty acids may interfere with the metabolism of essential fatty acids in the human organism.

OBJECTIVE

The objective was to investigate the relation between trans fatty acids and long-chain polyunsaturates in mature human milk.

DESIGN

Human milk samples (n=769) were obtained at the 6th week of lactation from mothers participating in a birth cohort study in Germany. The fatty acid composition of the milk samples was measured by high-resolution capillary gas-liquid chromatography.

RESULTS

trans Octadecenoic and trans octadecadienoic acids were inversely correlated with linoleic acid (r=-0.32 and -0.33, P<0.0001 for both), alpha-linolenic acid (r=-0.35 and -0.27, P<0.0001), arachidonic acid (r=-0.60 and -0.47, P<0.0001), and docosahexaenoic acid (r=-0.51 and -0.33, P<0.0001). In contrast, no inverse correlations were observed between trans hexadecenoic acid and polyunsaturated fatty acids.

CONCLUSIONS

The data obtained in the present study suggest that the availability of 18-carbon trans isomeric fatty acids may be inversely related to the availability of long-chain polyunsaturated fatty acids in mature human milk.