Dietary conjugated linoleic acid and body composition

Area of Science:

• Nutritional Science
• Biochemistry
• Human Physiology

Background:

• Conjugated linoleic acid (CLA) comprises positional and geometric isomers derived from linoleic acid.
• Primary dietary sources include ruminant meats and dairy products.
• The cis-9,trans-11 isomer is predominant in natural foods, while commercial products often contain equal amounts of cis-9,trans-11 and trans-10,cis-12 isomers.

Purpose of the Study:

• To review recent studies on CLA's effects on lipid metabolism, fat deposition, and body composition in animals and humans.
• To explore the proposed mechanisms underlying CLA's impact on obesity.

Main Methods:

• Review of existing scientific literature on conjugated linoleic acid.
• Analysis of studies investigating CLA's effects on animal and human physiology.
• Examination of proposed molecular and metabolic pathways.

Main Results:

• Animal studies indicate that CLA, particularly the trans-10,cis-12 isomer, can decrease fat deposition and lipid content.
• Observed adverse effects in animals include insulin resistance and fatty liver/spleen.
• Human studies suggest minimal impact on body weight and a lesser reduction in body fat compared to animal models.

Conclusions:

• CLA's effectiveness in reducing body fat appears significantly less pronounced in humans than in animals.
• Further human clinical trials are essential to validate potential benefits and establish safety recommendations.
• Postulated mechanisms involve modulation of energy intake, lipogenesis, energy expenditure, and fat oxidation.