Life History Theory and the Immune System

Ok, after a short, unavoidable, absence I am now back at work. Kaplan argues that the two most energy intense components of the human body are the brain and the immune system. This paper addresses some of the implications of immune system demands in the presence of nutritional constraints:

Life History Theory and the Immune System: Steps Toward a Human Ecological Immunology
Thomas W. MCDade

ABSTRACT Within anthropology and human biology, there is growing interest in immune function and its importance to the ecology of human health and development. Biomedical research currently dominates our understanding of immunology, and this paper seeks to highlight the potential contribution of a population-based, ecological
approach to the study of human immune function. Concepts from life-history theory are applied to highlight the major challenges and demands that are likely to shape
immune function in a range of ecological contexts. Immune function is a major component of maintenance effort, and since resources are limited, trade-offs are expected between investment in maintenance and other critical life-history functions involving growth and reproduction.

An adaptationist, life-history perspective helps make sense of the unusual developmental trajectory of immune tissues, and emphasizes that this complex system is designed to incorporate information from the surrounding ecology to guide its development. As a result, there is substantial population variation in immune development and function that is not considered by current biomedical approaches. In an attempt to construct a framework for understanding this variation, immune development is considered in relation to the competing life-history demands
that define gestation, infancy, childhood, adolescence, and adulthood. Each life stage poses a unique set of adaptive challenges, and a series of hypotheses is proposed
regarding their implications for immune development and function. Research in human ecological immunology is in its earliest stages, but this is a promising area
of exploration, and one in which anthropology is wellpositioned to make important contributions. Yrbk Phys Anthropol 46:100–125, 2003. © 2003 Wiley-Liss, Inc.