The term
conjugated linoleic acid (CLA) refers to a series of
linoleic acid isomers present in meat and diary products from ruminants that have their double bonds in a conjugated position. The aim of the present work was to study the effects of a CLA isomer, trans-10,cis-12, on cholesterolemia and biliary
lithiasis risk in an animal model of diet-induced
hypercholesterolemia. For that, two groups of hamsters were fed with a hypercholesterolemic diet supplemented with 0.5%
linoleic acid or with the trans-10,cis-12 CLA isomer, respectively. Daily food intake and weight were determined and, 6 weeks later, serum and bile samples were obtained, and livers and spleens were dissected and weighted. Cholesterolemia, hepatic and splenic
cholesterol content, and biliary
cholesterol phosnolipid and bileacid concentrations were determined; Biliary Lithogenic Index was calculated, and presence of
gallstones was assessed. CLA did not modify energetic intake or final
body weight, spleen size or spleen
cholesterol content, but it did significantly reduce total serum
cholesterol (-18%) at the expense of c-
LDL (-66%), and it also significantly reduced hepatic content of free
cholesterol (-26%), without changes in esterified
cholesterol. Besides, CLA produced a 32% increase in biliary
cholesterol concentration, a 28% increase in Lithogenic Index, and a higher incidence of biliary
lithiasis. Therefore, the present study shows that the CLA trans-10,cis-12 isomer is hypercholesterolemic since it increases, at least in part,
cholesterol secretion to the bile. As a consequence, this effect increases the risk for biliary
lithiasis.