Dietary fat and fatty acids are potential factors that affect the development of chronic diseases. It has recently been demonstrated in animal studies that conjugated linoleic
acid, a fatty acid specific for milk fat and lipids of ruminants, has anticarcinogenic properties; however, studies on human populations are needed.

The Finnish Mobile Clinic Health Examination Survey forms a large populationbased cohort in which the importance of fatty acids in relation to chronic diseases can be investigated, based on either dietary intake or presence of serum lipid fatty acids.

Here we describe the extent to which determination of the fatty-acid composition of serum total lipids in samples from the Mobile Clinic serum sample bank is usefull as a biomarker of exposure.