• DIET
• ENVIRONMENTAL HEALTH
• CANCER
• EPIDEMIOLOGY
• PUBLIC HEALTH POLICY

Food affects our health in so many ways, and epidemiology has long considered the role of diet in conditions such as obesity, diabetes, lipid metabolism, bone health and cancer. In addition to nutritional content, food may contain contaminants, additives and residues that derive from our ecosystem (through polluted soil or water), agricultural practices (pesticides, antibiotics), production processes, handling and preparation.1 Food is thus one of many threads linking the environment to exposure, and in the story of arsenic and chicken we pull on one thread only to be drawn to a tangle of complex issues.

In 2000, a biostatistics student came to the US Department of Agriculture (USDA) in search of a project to fulfil a requirement for his master's degree. This author pointed him to a database from the National Residue Program (NRP) containing the laboratory results of tests on samples of meat and poultry for a wide range of chemical residues, including veterinary drugs and pesticides.2 After an informal consultation with colleagues working on cancer research, the student was encouraged to focus on arsenic because of growing interest in various sources of arsenic exposure. Arsenic is a chemical element that occurs in nature in a variety of forms, inorganic and organic. It is well known as a poison by anyone who reads mysteries or the history of the Borgias, and with its long and colourful history, arsenic is not something that people want in their food.3 Environmental epidemiologists and others had been raising concerns about arsenic exposure in other foods (rice is an example), water (with extensive policy issues around acceptable levels in water) and documenting growing evidence about the health risks associated with environmental exposure to arsenic.4 ,5 Nearly every organ in the body can be affected by arsenic exposure, with health …