The effects of conjugated linoleic acid on human health-related outcomes

Abstract

Conjugated linoleic acid (CLA) is a collective term for a mixture of positional and geometric isomers of conjugated dienoic derivatives of linoleic acid. CLA has received considerable attention as a result of animal experiments that report anti-carcinogenic, anti-atherogenic and anti-diabetic properties, and modulation of body composition and immune function. Several studies of CLA supplementation in human subjects have now been published, but in contrast to animal studies there has been marked variation between reports on the health-related outcomes. The consensus from seventeen published studies in human subjects is that CLA does not affect body weight or body composition. Some detrimental effects of the trans-10,cis-12 CLA isomer have also been reported in terms of altered blood lipid composition and impaired insulin sensitivity. Finally, CLA has only limited effects on immune functions in man. However, there have been reports of some interesting isomer-specific effects of CLA on the blood lipid profile, but not on immune function. These isomer-specific effects need further investigation. Until more is known, CLA supplementation in man should be considered with caution.

Effect of dietary fatty acids on expression of lipogenic enzymes and fatty acid profile in tissues of bulls

“…Doran@uwe.ac.uk another PUFA, namely conjugated linoleic acids (CLAs). CLA is a group of isomers, which have been demonstrated to enhance immune system, to reduce body weight and to decrease the risk of cancer (Tricon et al, 2005;Bhattacharya et al, 2006). The main natural source of cis-9, trans-11 CLA is meat and milk of ruminants (Song and Kennelly, 2003).…”

Effect of dietary sources of roasted oilseeds on blood parameters and milk fatty acid composition

“…It is found predominantly in food products from ruminant animals, especially in milk products (Chin et al, 1992). Besides the anticarcinogenic property, CLA also enhances the immune response, increases the feed efficiency and reduces the body fat (Tricon et al, 2005). Recently, it has been reported that each CLA isomer may have a different pharmacological effect.…”

Differences between human subjects in the composition of the faecal bacterial community and faecal metabolism of linoleic acid

“…Evidence derived from studies in animal models and clinical trials indicates that CLA could have a number of beneficial effects on human health, including decreasing carcinogenesis and atherosclerosis, controlling body fat gain and enhancing the immune response as well as decreasing inflammation and other adverse effects typically associated with immune enhancement (McLeod et al, 2004;O'Shea et al, 2004;Wang & Jones, 2004;Lee et al, 2005;Tricon et al, 2005).…”

“…It has also been suggested that CLA inhibits the development of colorectal cancer Lampen et al, 2005;Lee et al, 2005; Beppu et al, 2006). Positional and geometric isomers of CLA may have different physiological effects in humans (Tricon et al, 2005). It is therefore important to understand the formation of specific isomers of CLA during LA metabolism in relation to gut health.…”