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CeSSIAM, Guatemala City, Guatemala
volume 84 of World Review of Nutrition and Dietetics, edited by Artemis P Simopoulos, 1999, 145 pages, hardcover, $132.25. S Karger AG, Basel, Switzerland.
The 84th volume of the World Review of Nutrition and Dietetics series is, in many ways, an extension of its most recent companions, concentrating on genetic variation and genetic determination of the interaction of diet and health. The 5 essays, composed of 17 figures and 21 tables, compiled by the editor Artemis Simopoulos under the title of Evolutionary Aspects of Nutrition and Health: Diet, Exercise, Genetics and Chronic Disease would have been favored reading of James Fenimore Cooper because they extol the life and times (and lifestyle and dietary practices) of the noble savage, ie, the tribal hunter-gatherer of antiquity. A common thread in all contributions are the assumptions of paleonutrition as popularized by SB Eaton; namely, that the hunter-gatherer (caveman) lifestyle and diet dominated the genetic evolution of hominids, leading to Homo sapiens. Only within the past 500 generations of humankind has our diet changed from a fare of largely game meat to the domesticated seeds of wild grasses that we call wheat, rice, barley, and maize. The essayists focus on the origins of chronic diseases in readable, erudite, and well-documented (686 bibliographic citations) arguments.
The consensus of all 5 contributions is that humans were bigger, more physically fit, and better nourished during the Pleistocene era than since the development of settled agriculture. The obvious question would be, "Why were there then so few of these humans and why were their lives so precarious and their lifespans so short?" Their lives were precarious because their prey moved around a great deal and had to be subdued with primitive clubs and spears in hand-to-claw combat; their lives were short because infections, complications of childbirth, infanticide, fratricide, tribal conflict, and hunting accidents (the prey becoming the predator) rarely allowed anyone to reach the ages in which senescent processes allow for the emergence of degenerative diseases such as diabetes, osteoporosis, cancer, and circulatory ailments. It was no accident that the earth's total number of inhabitants stagnated for millennia and has only exploded in later stages of the agricultural era. Indeed, were it not for a sedentary lifestyle and greater food security, the stratification of society and the leisure to write essays would never have evolved. The analysis of diet, lifestyle, and genetics is interesting, but the differential role of survival to greater longevity is ignored at the peril of a comprehensive analysis.
Loren Cordain provides a comprehensive history of the evolution of agriculture and the current worldwide production and consumption of cereal and pulses. Although admitting that food security is dependent on the domestication of our food animals and plants, Cordain's bias is negative (antiagriculture), emphasizing the deficiencies of micronutrients and imbalance of essential amino acids and forcing a litany of potential adverse health effects of nonnutrient and antinutrient constituents of edible plants. Autoimmune disease is seen by Cordain as being generated by the confrontation of the immune system with phytoantigens.
In a brief tour of the physical activity history of humankind, Ji Di Chen coins a novel and useful term: exercise deficiency. The lifestyle that allows us to chronicle history also exposes us to a deficit in the running that our ancestors "enjoyed" behind the herds of mastodons. It also makes our bones and cardiovascular systems more susceptible to breaks and breakdowns.
One serious and important controversy, that of the differential susceptibility of ethnic groups from developing countries and indigenous populations to type 2 diabetes, is explored from distinct angles. James V Neel of Michigan, the original proposer of the thrifty gene hypothesis 38 y ago, updates the evidence for his theory in the first chapter; this discussion emphasizes the persistence of vigorous daily energy expenditure. Janette C Brand-Miller and Stephen Colaguiri of Sydney, Australia, are the authors of the "carnivore connection." They revised the estimate of the plant-to-animal partition of the dietary energy intake of early hominids from 65:35 to 35:65. They based this, in part, on observations of contemporary hunter-gatherers. Their hypothesis states that a low-carbohydrate, high-fat (carnivorous) diet induces insulin resistance as the prevailing genotype; chronic consumption of plant foods with high glycemic indexes induces high plasma glucose concentrations, the antecedent of the diabetic condition.
The contributions are, with the exception of one chapter, heavy on theory and light on data, and the logical thinking mobilized to support the theoretical constructs itself ranges from light to profound. The book offers tension between the questions of "How did we get here?" and "Where should we go now?" There is subtle irony as the various authors try to grapple with conclusions.
The origin of the human species is essentially the tribal collective, in which hierarchy and cohesion were supreme. Individuality was anathema to the collective survival of our ancestors, so lauded in this book. Ironically, the lessons derived from this survey of genetic variation and response to diet feed into an argument for individualism and atomization that defies the possibility of formulating public policy. Thus, very thought provoking are the final comments by the series editor and the author of the concluding chapter based on the book's title. Simopoulos derives the following as her central lesson: "In developing RDIs [recommended dietary intakes], genetic variants in the population should be taken into consideration...Universal dietary recommendations have been used by nutritionists who were concerned with undernutrition, but universal dietary recommendations are not appropriate when the problem is one of overnutrition. Individual dietary recommendations taking into consideration genetic predispositions and energy expenditure are in order." Ironically, in affluent countries, it is likely that our technology to assess genetic constitution and alter it will indeed outstrip our techniques for effecting dietary and lifestyle changes. In developing countries, in which chronic diseases are rapidly emerging, individualization of genetic diagnosis will be no more available, accessible, or affordable to the poor than are anti-HIV medications.
This volume brings forth few new facts, but provides an example of how essayists can address common (albeit disputed) assumptions and frame them into an essential discussion posed by worldwide endemic chronic disease. Diet, exercise, lifestyle, and genetic selection are clearly worth pondering and weaving into the tapestry. Would that the issue of increased survival to older age had played a larger role in the reflections. The observation is that, for early humans, life was precarious, intense, and short; for 21st century humans, life is more secure, more leisurely, more contemplative, and longer, forcing us to reap the bitter experience of chronic disease along with the sweetness of the foods and comforts that technologic progress has wrought.