Biomarkers and the measurement of fatty acids.

OBJECTIVE: To review the various biomarkers of dietary intakes of fatty adds in human populations, their measurement, limitations and analytical considerations.
DESIGN: Review of the literature.
RESULTS: Although there is no good biomarker of intake of total fat, a number of alternatives exist for assessing the intakes of exogenously produced fatty acids that are consumed. Adipose tissue, erythrocyte membrane concentrations and serum or plasma levels can reflect prior intakes over the past few hours to the past few years. The concentrations of individual fatty acids in these media generally reflect relative levels, and are influenced by a number of factors. Although relatively expensive to analyse, a single analysis by gas chromatography or high-performance liquid chromatography provides information on multiple fatty acids, and is superior to attempting to measure specific fatty acids using traditional dietary assessment methods.
CONCLUSIONS: Biomarkers of fatty acids that reflect long-term intake are available for nutritional epidemiology purposes. Analytical methods have become very accurate and able to detect and quantify smaller families, such as trans-fatty acids.