Nutrition impact of conjugated linoleic acid: A model functional food ingredient

Abstract

Many lipid molecules provide health benefits beyond their basis nutritional values and are included under the chemical classification of polyunsaturated fatty acids (PUFA). Because of their immunomodulatory and anti-inflammatory properties, conjugated linoleic acid (CLA) and ω-3 PUFA can also be defined as nutraceuticals. CLA is a mixture of positional (i.e., 9,11;10.12;or 11.13) and geometric (i.e., cis or trans) isomers of octadecadienoic acid. The CLA mixture has been shown to have anticarcinogenic, antiatherosclerotic, and immunomodulatory properties, but there is little or no evidence as to which of the individual isomers is the most important in mediating these health benefits. The mechanism by which dietary CLA influences immune function could involve regulation of lipid mediator synthesis, and/or transcriptional regulation of gene expression by peroxisome proliferator activated receptor-γ. However, these explanations have not been completely accepted in terms of defining the mechanism(s) regulating functional activity because of the lack of molecular evidence in vivo. Other PUFA within the category of nutrients that modulate health (e.g., α-linolenic or eicosapentanoic acid) are immunosuppressive. Conversely, dietary CLA expanded CD8+ lymphocytes and thymocytes (i.e., CD8+ and double negative) in vivo, and enhanced proliferation of CD8+ lymphocytes ex, vivo. In addition, CLA decreased the tissue damage caused by bacterial-induced colitis. All these properties make dietary CLA a substance that provides medical or health benefits, including the prevention or treatment of diseases (e.g., nutraceutical).