Fatty acid composition of serum lipids: is this marker of fat intake still relevant for identifying metabolic and cardiovascular disorders?

Analysis of the fatty acid composition of serum lipid fractions is an old but still useful method for several purposes. The proportions of essential polyunsaturated and trans fatty acids are biomarkers of dietary intake that can be used to improve estimates of fatty acid intake in dietary trials and population studies. Furthermore, the metabolism of essential n-6 and n-3 fatty acids is reflected in the serum fatty acid composition. Changes in the activity of the delta-6 and delta-5 desaturases, which affect the proportions of dihomogamma-linolenic acid and arachidonic acid in serum lipids, are associated with insulin resistance and may explain differences in coronary heart disease risk.