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Contribution of vaccenic acid in CLA-enriched cheese to CLA status in humans

Dairy products have had a bad reputation from a nutritional point of you because of the presence of TFA. In the last 20 years several evidences have been published that TFAs possess detrimental effects, even more than SFA, because they not only increase LDL cholesterol but also decrease HDL cholesterol when the daily intake is higher than 2 % of en. Several studies have even elucidated a possible mechanism by which saturated and tFAs may influence cholesterolemia.

The detrimental effects of tFAs, however, have also been extended to those present in animal fat. In fact, tFAs are formed not only during industrial partial hydrogenation but also by a biohydrogenation performed by anaerobic bacteria present in the rumen through a sequence of enzymatic reactions.

However, there are substantial differences between tFAs from these two types of fat. The formation by enzymatic reactions leads only to a few isomers of tFAs from animal origin. During industrial hydrogenation randomly distributed isomers are produced. Furthermore, the major product of biohydrogenation, vaccenic acid (t11-18:1), has been shown to be an efficient precursor of rumenic acid (c9,t11 CLA) both in animals and humans,. and therefore can be regarded as an intermediate product.

One of the aim of our study was to evaluate the contribution of vaccenic acid present in the CLA-enriched cheese to CLA plasma levels in humans. At this scope we first evaluate the bioavailability of c9,t11 CLA with the administration to human volunteers increasing concentration of synthetic pure c9,t11 CLA in triglyceride form.

The equation of the curve built with the value of synthetic c9,t11CLA daily intake and its corresponding plasma levels, allowed us to determine VA contribution to c9,t11 CLA plasma levels in the same volunteers with a known amount of CLA-enriched cheese. Our data show that VA significantly contributed to c9,t11 CLA plasma levels within a range of conversion between 15 to 18%.

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Reported by

Università degli Studi di Cagliari (UCDBS)
Dipartimento di Biologia Sperimentale, Sezione di Patologia Sperimentale, Cittadella Universitaria, Monserrato
09042 Cagliari