The natural docosenoic acid in the human diet can be predominantly 22:1 omega 9 if of plant (generally rapeseed oil) origin, or predominantly 22:1 omega 11 if of marine origin. The fatty fatty acids of dietary fats (meals) and plasma lipids of some Greenland eskimos were examined by open-tubular gas-liquid chromatography. The dietary docosenoic acid isomer distribution pattern showed 22:1 omega 11 to be about 5 times 22:1 omega 9, a ratio typical of marine mammal fats. A similar ratio was also found in the plasma fatty acids, but with a slightly higher proportion of 22:1 omega 9. When correlated with the excellent cardiovascular health of Greenland eskimos, the docosenoic acid data suggest that current concern as to the impact of dietary docosenoic acids on the human myocardium, largely based on animal feeding studies, may be exaggerated.