Salmon and malnutrition on the Northwest Coast

How ancestral subsistence strategies solve salmon starvation and the "protein problem" of Pacific Rim resources

This article provides a theoretical treatment of hunter-gatherer diet and physiology. Through a synthesis of nutritional studies, informed by ethno-archaeological data, we examine the risk of protein-rich diets for human survival, and how societies circumvent "salmon starvation" in the northeastern Pacific Rim. Fundamental nutritional constraints associated with salmon storage and consumption counter long-standing assumptions about the engine of cultural evolution in the region. Excess consumption of lean meat can lead to protein poisoning, termed by early explorers "rabbit starvation." While consumption of fats and carbohydrates is widely portrayed as a pathway to "offsetting" protein thresholds, there are true limits to the amount of protein individuals can consume, and constraints are most extreme for smaller individuals, children, and pregnant/nursing mothers. While this problem is not usually perceived as associated with fish, the risk of protein poisoning limits the amount of low-fat fish that people can eat safely. Compared with smaller, mass-harvested species (e.g., eulachon), dried salmon are exceedingly lean. Under certain circumstances fattier foods (small forage fish, marine mammals, whales, and even bears) or carbohydrate-rich plants may have been preferred not just for taste but to circumvent this "dietary protein ceiling." Simply put, "salmon specialization" cannot evolve without access to complimentary caloric energy through fat-rich or carbohydrate-rich resources. By extension, the evolution of storage-based societies requires this problem be solved prior to or in tandem with-salmon intensification. Without such solutions, increased mortality and reproductive rates would have made salmon reliance unsustainable. This insight is in line with genomic research suggesting protein toxicity avoidance was a powerful evolutionary force, possibly linked to genetic adaptations among First Americans. It is also relevant to evaluating the plausibility of other purportedly "focal" economies and informs understanding of the many solutions varied global societies have engineered to overcome physiological protein limits.

Dietary inferences through buccal microwear analysis of middle and upper Pleistocene human fossils

Buccal microwear has been studied in a sample of 153 molar teeth from different modern hunter-gatherer, pastoralist, and agriculturalist groups, with different diets (Inuit, Fueguians, Bushmen, Australian aborigines, Andamanese, Indians from Vancouver, Veddahs, Tasmanians, Lapps, and Hindus), preserved at museum collections. Molds of an area of the buccal surface have been obtained and observed at 100x magnification in a scanning electron microscope (SEM). The length and orientation of each striation have been determined with a semiautomatic program of an image analyzer system (IBAS). Results show that intergroup variability is significantly higher than the intragroup variability. There exists a tendency toward fewer striations and a higher proportion of vertical striations in the carnivorous groups than in the vegetarian ones. This microwear pattern is concordant with biomechanics (predominantly vertical mandible movements in meat eaters) and phytolith content in plants (more abrasive particles in vegetarian diets). The variability found has been used in a multivariate analysis as a base to compare the microwear pattern of a sample of 20 Middle and Upper Pleistocene fossils, mainly from Europe, analyzed with the same methodology. The sample includes specimens usually classified as archaic H. sapiens (Broken Hill, Banyoles, Montmaurin, La Chaise-Suard, La Chaise-Bourgeios et Delaunay), Neanderthal (La Quina V, Gibraltar 2, Tabun 1 and 2, Amud 1, Malarnaud, St. Cesaire, Marillac), and anatomically modern H. sapiens (Skhül 4, Qafzeh 9, Cro-Magnon 4, Abri-Pataud, Veyrier, La Madelaine, Rond-du-Barry). Results indicate that some of the Neanderthal specimens have a microwear pattern close to that of the carnivorous groups (such as Inuit and Fueguians), suggesting that these individuals follow a hunter strategy. In contrast, archaic H. sapiens and H. sapiens sapiens seem to have a more abrasive diet, probably more depending on vegetable materials, than the Neanderthals.