Meat consumption trends and health: casting a wider risk assessment net.

Humans come from a long line of meat-eaters. For much of the past two million years our hominid forebears have been evolving from scavenging to systematic hunting. This trend was intimately coupled with the evolution of the human brain, which now is much larger and more complex than was the brain of our mostly vegetarian australopithecine ancestors. In many hunter-gatherer communities meat became a major, even the majority, source of dietary energy. The ethics and aesthetics of carnivory aside, meat is a high-grade source of nutrients. Furthermore, across many cultures and stages of economic development, meat (especially red meat) is regarded as a desirable food, and an increase in meat consumption therefore figures prominently in the ‘nutrition transition’. We modern urban citizens come from a very short line of consumers of large amounts of (mostly) industrially produced (‘factory-farmed’) meat. This supermarket meat differs profoundly from wild game meat, especially in lipid profile and chemical pollutant content. Further, modern meat production is distinguished by the amount of environmental and ecological damage that it causes, including via substantial energy inputs. The paper by Polly Walker and colleagues in the present issue breaks important new ground in exploring the ‘Public health implications of meat production and consumption’. The paper is significant in two senses. First, the authors frame their question in population terms, thus looking beyond the main focus of textbook epidemiology that examines inter-individual differences in ‘exposure’ that account for the occurrence of disease cases. Their interest is in accounting for changes in rates of disease as a function of shifts in cultural patterns of food production and consumption. Second, their exploration of the spectrum of health consequences extends to considering the collateral damage to the environment (‘externalities’) and the resultant risks to health. This invites epidemiologists to address the wider vista of ecological changes and their population health consequences in a world in which rapid social and environmental changes occur on an increasingly large scale. The authors encapsulate the foreground risks to health thus: