title: Latitude, local ecology, and hunter-gatherer dietary acid load: implications from evolutionary ecology.
abstract: BACKGROUND
  Past estimations of the net base-producing nature of the Paleolithic "Diet of Evolutionary Adaptedness" derived primarily from interpretations of ethnographic data of modern historically studied hunter-gatherers. In our recent ethnographic analyses, we observed large variations in diet-dependent net endogenous acid production (NEAP) among hunter-gatherer diets.
  
  
  OBJECTIVE
  We proposed to determine whether differences in ecologic environments influence estimations of NEAP.
  
  
  METHODS
  By using ethnographic data of plant-to-animal subsistence ratios and mathematical models established previously, we computed frequency distributions of estimated NEAP in relation to latitude in 229 worldwide modern hunter-gatherer societies. Four different models of animal fat density were used: models A (3%), B (10%), C (15%), and D (20%). In addition, we estimated NEAP by primary ecologic environments in those hunter-gatherer societies (n = 63) for which data were documented.
  
  
  RESULTS
  With increasing latitude intervals, 0°-10° to >60°, NEAP increased in all 4 models. For models A, B, and C, the diets tend to be net acid-producing at >40° latitude and net base-producing at <40°; the same held for model D (>50° and <50°, respectively). For models A, B, and C, the diets of hunter-gatherers living in northern areas (tundra and coniforest) and in temperate grassland and tropical rainforests are net acid-producing. In all other ecologic niches, hunter-gatherers seem to consume a neutral or net base-producing diet.
  
  
  CONCLUSIONS
  Latitude and ecologic environments codetermine the NEAP values observed in modern hunter-gatherers. The data support the hypothesis that the diet of Homo sapiens' East African ancestors was predominantly net base-producing.
authors: Nutrition Physiology and Human Nutrition Unit, Institute of Food Science and Human Nutrition, Leibniz University of Hannover, Hannover, Germany.
authors: Alexander
authors: A
authors: Ströhle
authors: Andreas
authors: A
authors: Hahn
authors: Anthony
authors: A
authors: Sebastian
mesh_terms: D000064:Acclimatization; D000818:Animals; D005075:Biological Evolution; D004032:Diet; D017753:Ecosystem; D004777:Environment; D005007:Ethnology / Q000379:methods; D005843:Geography; D015186:Hominidae; D006801:Humans; D010163:Paleontology