Relationship between the degree of unsaturation of dietary fatty acids and adipose tissue fatty acids assessed by natural-abundance 13C magnetic resonance spectroscopy in man.

Natural-abundance 13C magnetic resonance spectroscopy was used for determining noninvasively the relative concentration of mono- and polyunsaturated fatty acids of adipose tissue in two groups of volunteers. The first consisted of subjects who had followed a fat-reduced diet for at least half a year before the 13C measurements. The second were control subjects who were on a usual high-fat diet. The ratio of unsaturated to total fatty acids in adipose tissue determined by 13C MRS correlated significantly with the same ratio in fat of the diet composition estimated by a dietician according to food records. The results indicate that 13C MRS is capable of assessing the degree of unsaturation of dietary fatty acids consumed during the preceding months.