Dietary long chain n-3 fatty acids are more closely associated with protein than energy intakes from fat.

The n-3 fatty acids, eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) regulate hepatic lipid and glucose metabolism; however, EPA and DHA are naturally present in human diets in foods of animal origin, which are generally high in protein with variable triglycerides and uniformly low amounts of carbohydrate. We used dietary information for 611 individuals of 1.5-66 years to address whether EPA and DHA are associated with protein, but not fat intake. EPA, DHA and arachidonic acid (20:4n-6) intakes were positively associated with protein, but not fat intake, whereas linoleic acid (18:2n-6) and α-linolenic acid (18:3n-3) intakes were positively associated with fat, but not protein intake. Children 1-3 years of age have lower EPA and DHA intakes than children over 4 years or adults. Recommendations regarding EPA and DHA intake should focus on protein sources, rather than diet fat, and consider their potential roles in amino acid and protein metabolism.