Estimation of the net acid load of the diet of ancestral preagricultural Homo sapiens and their hominid ancestors123

https://doi.org/10.1093/ajcn/76.6.1308Get rights and content
Under an Elsevier user license
open archive

ABSTRACT

Background:

Natural selection has had < 1% of hominid evolutionary time to eliminate the inevitable maladaptations consequent to the profound transformation of the human diet resulting from the inventions of agriculture and animal husbandry.

Objective:

The objective was to estimate the net systemic load of acid (net endogenous acid production; NEAP) from retrojected ancestral preagricultural diets and to compare it with that of contemporary diets, which are characterized by an imbalance of nutrient precursors of hydrogen and bicarbonate ions that induces a lifelong, low-grade, pathogenically significant systemic metabolic acidosis.

Design:

Using established computational methods, we computed NEAP for a large number of retrojected ancestral preagricultural diets and compared them with computed and measured values for typical American diets.

Results:

The mean (± SD) NEAP for 159 retrojected preagricultural diets was −88 ± 82 mEq/d; 87% were net base-producing. The computational model predicted NEAP for the average American diet (as recorded in the third National Health and Nutrition Examination Survey) as 48 mEq/d, within a few percentage points of published measured values for free-living Americans; the model, therefore, was not biased toward generating negative NEAP values. The historical shift from negative to positive NEAP was accounted for by the displacement of high-bicarbonate-yielding plant foods in the ancestral diet by cereal grains and energy-dense, nutrient-poor foods in the contemporary diet—neither of which are net base-producing.

Conclusions:

The findings suggest that diet-induced metabolic acidosis and its sequelae in humans eating contemporary diets reflect a mismatch between the nutrient composition of the diet and genetically determined nutritional requirements for optimal systemic acid-base status. Am J Clin Nutr 2002;76:–16.

KEY WORDS

WORDSNutrition
evolution
acid base
dietary net acid load
protein
cereal grains
energy-dense
nutrient-poor foods

Cited by (0)

1

From the Department of Medicine and the General Clinical Research Center, University of California, San Francisco.

2

Supported by NIH grants RO1-AG/AR0407 and RO1-HL64230; the study used the resources of the University of California, San Francisco/Moffitt General Clinical Research Center (NIH grant MO1 RR-00079).

3

Address reprint requests to A Sebastian, 40 Crags Court, San Francisco, CA 94143. E-mail: [email protected].