The purpose of the study is to investigate the effects of Conjugated Linoleic Acid (CLA) from dairy products on fatty acid metabolism and human health. A CLA depletion-repletion study was carried out with healthy volunteers. CLA depletion was achieved through an eight-week dairy fat restriction, followed by an eight-week repletion period consisting of intake of a butter naturally enriched with CLA. Changes in body composition, fasting glucose and insulin, inflammatory mediators, cell membranes' stability, plasma lipid levels and fatty acid composition of lipid classes are evaluated after depletion and repletion phases.

After collecting baseline blood samples, CLA-depletion phase started with dietary orientation, by a registered dietitian, to the study subjects (n=29) to exclude from their diets any type of dairy fat for the following 8 weeks. Blood samples were taken at the end of CLA-depletion, and CLA-repletion phase was initiated by dietitians' instructions: volunteers returned to their regular diets, and additionally consumed a CLA-enriched butter for another 8-week period. Blood samples were taken at the end of the CLA-repletion phase. The effects of CLA on the following parameters were evaluated: inflammatory mediators; fatty acid composition of erythrocytes, plasma phospholipids and cholesterol esters; body composition; clinical factors associated with the metabolic syndrome and indicators of cell membranes' stability.

Inclusion Criteria:

• Healthy volunteers;
• 20 to 40 years;
• BMI between 18.0 and 29.9 kg/m2.

Exclusion Criteria:

• Use of dietary supplements;
• Smoker;
• Alcoholic;
• Under medication;
• History of chronic disease