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The role of dairy products in supplying conjugated linoleic acid to man's diet: a review

Published online by Cambridge University Press:  14 December 2007

Ruth E. Lawson ,
Angela R. Moss  and
D. Ian Givens
Ruth E. Lawson*
Affiliation:
ADAS Bridgets Dairy Research Centre, Martyr Worthy, Winchester SO21 1AP, UK
Angela R. Moss
Affiliation:
ADAS Nutritional Sciences Research Unit, Alcester Road, Stratford-upon-Avon, Warwickshire CV37 9RQ, UK
D. Ian Givens
Affiliation:
ADAS Nutritional Sciences Research Unit, Alcester Road, Stratford-upon-Avon, Warwickshire CV37 9RQ, UK
*
*Corresponding author: Dr Ruth E. Lawson, present address Department of Land-based Studies, Nottingham Trent University, Brackenhurst, Nottingham Road, Southwell, Nottinghamshire NG25 0QF, UK, fax +44 1636 815 404, email [email protected] uk
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Abstract

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Health benefits for man have been associated with conjugated linoleic acid (CLA) and dairy products are highlighted as offering the best opportunity to increase CLA consumption. CLA is synthesised in the rumen as an intermediate in the biohydrogenation of linoleic acid to stearic acid. The supplies of both intermediates and endproducts of biohydrogenation are affected by the substrate supply and extent of biohydrogenation, thus influencing the CLA content of milk from ruminants. The majority of CLA is present in the rumen in the form of the cis-9,trans-11 isomer. The transfer efficiency of CLA to milk fat is affected by the presence of different isomers of CLA. Ruminant mammary and adipose cells are able to synthesise cis-9,trans-11-CLA from trans-11-18:1 (vaccenic acid) by the action of the Δ9-desaturase enzyme. Plant oils are high in both linoleic and linolenic acids, which results in increased CLA production in the rumen and in the mammary gland. The CLA content of milk increases when cows are offered grazed grass. Many published studies examining the CLA concentration of processed milk were confounded by variations in the concentration of CLA in the raw milk.

Keywords

Conjugated linoleic acidDairy productsRuminants
Type
Research Article
Information
Nutrition Research Reviews , Volume 14 , Issue 1 , June 2001 , pp. 153 - 172
Copyright
Copyright © CABI Publishing 2001

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