Indigenous Subarctic Food Systems in Transition: Amino Acid Composition (Including Tryptophan) in Wild-Harvested and Processed Meats

Indigenous people of northern Canada traditionally lived a nomadic lifestyle subsisting on wild game and fsh for thousands of years. With colonization came an increasing dependence on imported processed foods. Tis dietary change has ofen been reported to be one of the factors leading to Indigenous health and wellbeing disparities worldwide. We determined the amino acid (AA) profle including tryptophan (Trp) of wild meats (game and fsh) and processed meats found in the traditional and modern diets of Indigenous subarctic communities in Canada. Trp is a limited essential AA necessary for synthesis of serotonin (5-HT), an important neurotransmitter and homeostatic regulator. Te dietary ratio of Trp relative to other large neutral AAs (LNAA) can alter Trp transport and 5-HT synthesis in the brain. We determined AA composition of wild meats and processed meats using standardized NaOH and HCl hydrolysis for Trp and other AAs, respectively, followed by ultraperformance liquid chromatography. A Principal Components Analysis revealed that overall AA composition is signifcantly diferent between wild and processed meats. (M)ANOVA showed signifcantly higher protein in wild meats (wet weight, ww). Trp was signifcantly lower in processed meat samples (n=15; 0.18g/100g ± 0.02 ww) compared to wild meat samples (n=25; 0.24g/100g ± 0.06 ww). Te proportion of Trp:LNAA and Trp in sample protein were not signifcantly diferent between wild (1:21-1:27, 0.92-1.27 g/100g protein) and processed (1:20-1:24, 1.03-1.27 g/100g protein) meats. Within wild meats, AA composition is signifcantly diferent between fsh and waterfowl, fsh and moose, and moose and goose. (M)ANOVA results indicate signifcantly higher protein in goose compared to moose and fsh and in moose compared to fsh. We compared our Trp fndings to previous analyses and discuss the substantial gap in human nutritional studies of Trp.