Conjugated linoleic acids, atherosclerosis, and hepatic very-low-density lipoprotein metabolism

Abstract

Conjugated linoleic acids (CLAs) are isomeric forms of the 18:2 fatty acid that contain conjugated sites of unsaturation. Although CLAs are minor components of the diet, they have many reported biological activities. For nearly a decade, the potential for CLA to modify the atherosclerotic process has been examined in animal models, and studies of supplementation of the human diet with CLA were started with the anticipation that such an intervention could also reduce the risk of cardiovascular disease. Central to the hypothesis is the expectation that dietary modification could alter plasma lipid and lipoprotein metabolism toward a more cardioprotective profile. This review examines the evidence in support of the hypothesis and the mechanistic studies that lend support for a role of CLA in hepatic lipid and lipoprotein metabolism. Although there are still limited studies in strong support of a role for CLA in the reduction of early atherosclerotic lesions, there has been considerable progress in defining the mechanisms of CLA action. CLA could primarily modulate the metabolism of fatty acids in the liver. The tools are now available to examine isomer-specific effects of CLA on hepatic lipid and lipoprotein metabolism and the potential of CLA to modify hepatic gene expression patterns. Additional animal and cell culture studies will increase our understanding of these unusual fatty acids and their potential for health benefits in humans.

Intake of milk, but not total dairy, yogurt, or cheese, is negatively associated with the clustering of cardiometabolic risk factors in adolescents

“…It has long been described that the milk fat produced from the pasture is rich in unsaturated fatty acids, including trans-octadecenoic acids and conjugated isomers of linoleic acid [45] and [46]. The conjugated isomers of linoleic acid has been associated with improving dyslipidemia and the proinflammatory state related to obesity and the MetS [47], [48] and [49]. Emerging scientific findings also indicate that such milk fat components as butyric acid may favor fat oxidation and decrease glycogen use [50].…”

Conjugated linoleic acid inhibits glucose metabolism, leptin and adiponectin secretion in primary cultured rat adipocytes

“…CLA has been studied extensively due to its potential beneficial effects in several disease states including cancer (Belury, 2002), atherosclerosis (McLeod et al, 2004), diabetes (Houseknecht et al, 1998), and obesity (Wang et al, 2004). CLA has also been reported to increase immune function (O'Shea et al, 2004).…”

Adverse effects of conjugated alpha-linolenic acids (CLnA) on lipoprotein profile on experimental atherosclerosis in hamsters

“…CLAs have unique biological properties (McLeod et al, 2004) among which an important but controversial observation is that CLA can alter lipoprotein metabolism and decrease the extent of atherosclerosis in experimental animals. For example, in rabbits, Lee et al (1994) demonstrated that a mixture of CLA isomers reduces both low-density lipoprotein (LDL) cholesterol and arterial lipid accumulation.…”