Classification studies, experimental design

The translation of results from animal studies into a useful paradigm in humans has represented a major roadblock in CLA research. In many occasions, very impressive differences between groups found throughout the course of animal experimentation were diluted or absent when human intervention studies were performed. An example of these controversial results was observed when the decrease in body fat observed in humans is significantly less than that anticipated based on the results from animal studies. Terpstra conducted a meta-analysis on the effects of CLA on body composition and plasma lipids. Terpstra accounted for differences in CLA composition/intake, study design, energy intake, and initial BMI between studies to explain differential responses to CLA treatment (62). However, a classification of subjects on the basis of PPAR y and 8 polymorphisms was not considered. We propose that PPAR y and 8 polymorphisms may account for differential responses to CLA treatment. Consequently, subjects could be classified as responders or non-... 

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