British Journal of Nutrition

Human and Clinical Nutrition

The effect of triacylglycerol-fatty acid positional distribution on postprandial metabolism in subcutaneous adipose tissue

Lucinda K. M. Summersa1, Barbara A. Fieldinga1, Vera Ilica1, Paul T. Quinlana2 and Keith N. Frayna1 c1

a1 Oxford Lipid Metabolism Group, Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford OX2 6HE, UK

a2 Unilever Research Colworth Laboratory, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK

Abstract

We hypothesized that fatty acids at the sn−2 position of chylomicron triacylglycerol are preferentially released into the venous plasma (rather than being taken up and stored in the adipocytes) after hydrolysis by lipoprotein lipase (EC 3.1.1.34) in adipose tissue. Arterio–venous differences across adipose tissue were studied in eight healthy subjects on two occasions for 6 h after ingestion of different structured triacylglycerols rich in palmitic acid either at the sn−2 or the sn−1,3 positions. In particular the specific fatty acids making up lipoprotein fractions and plasma non-esterified fatty acids were analysed. After the different meals there were no differences between either postprandial arterialized or venous plasma metabolite concentrations. Chylomicron triacylglycerol extraction in adipose tissue was the same following the two types of fat. There was no difference between the specific fatty acid composition of the postprandial non-esterified fatty acid release from adipose tissue after ingestion of the two triacylglycerols, indicating that there was no preferential release of a saturated fatty acid at the sn−2 position.

(Received March 06 1997)

(Revised June 26 1997)

(Accepted September 02 1997)

Correspondence:

c1 *Corresponding author: Dr K. N. Frayn, fax +44 (0)1865 224652, email keith.frayn@oxlip.ox.ac.uk

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