Variation in carbon isotope values among chimpanzee foods at Ngogo, Kibale National Park and Bwindi Impenetrable National Park, Uganda.

Stable isotope values in primate tissues can be used to reconstruct diet in the absence of direct observation. However, in order to make dietary inferences, one must first establish isotopic variability for potential food sources. In this study we examine stable carbon isotope (δ(13) C) values for chimpanzee (Pan troglodytes) food resources from two Ugandan forests: Ngogo (Kibale National Park), and Bwindi Impenetrable National Park.

Chimpanzee isotopic ecology: a closed canopy C3 template for hominin dietary reconstruction.

The most significant hominin adaptations, including features used to distinguish and/or classify taxa, are critically tied to the dietary environment. Stable isotopic analyses of tooth enamel from hominin fossils have provided intriguing evidence for significant C4/CAM (crassulacean acid metabolism) resource consumption in a number of Plio-Pleistocene hominin taxa. Relating isotopic tooth signatures to specific dietary items or proportions of C3 versus C4/CAM plants, however, remains difficult as there is an ongoing need to document and quantify isotopic variability in modern ecosystems.

Diurnal variation in nutrients and chimpanzee foraging behavior.

Primate feeding behavior varies over long (e.g., weekly, seasonally, yearly) and short (e.

Diurnal variation in glutathione and cysteine redox states in human plasma.

Background: Plasma glutathione/glutathione disulfide (GSH/GSSG) and cysteine/cystine (Cys/CySS) couples are oxidized in humans in association with oxidative stress and cardiovascular disease risk. Animal studies show that both pools undergo diurnal variations associated with dietary intake of sulfur amino acids.

Objective: The objective of this study was to determine whether the redox state of GSH, Cys, GSH/GSSG, or Cys/CySS undergoes diurnal variation in healthy adults.

Docosahexaenoic acid biosynthesis and dietary contingency: Encephalization without aquatic constraint.

Reconstructing evolutionary processes in the distant past is necessarily an inductive endeavor, typically appealing to numerous considerations thought to be relevant to the veracity of a particular conclusion. In this respect, it is essential that the considerations invoked to support hypotheses are in turn well-established truths. It is with these concerns that we sought to examine the nutritional, physiological, and archeological premises underlying the perspective that access to an aquatic diet rich in docosahexaenoic acid (DHA, 22:6n-3) was critical to human brain evolution (Carlson and Kingston [2007]: Am J Hum Biol 19:132-141).

Docosahexaenoic acid, the aquatic diet, and hominin encephalization: difficulties in establishing evolutionary links.

Distinctive characteristics of modern humans, including language, tool manufacture and use, culture, and behavioral plasticity, are linked to changes in the organization and size of the brain during hominin evolution. As brain tissue is metabolically and nutritionally costly to develop and maintain, early hominin encephalization has been linked to a release of energetic and nutritional constraints. One such nutrient-based approach has focused on the n-3 long-chained polyunsaturated fatty acid docosahexaenoic acid (DHA), which is a primary constituent of membrane phospholipids within the synaptic networks of the brain essential for optimal cognitive functioning.