Lead exposure, interactions and toxicity: food for thought

The recognition that nutritional status plays a role in altering susceptibility to lead absorption and toxicity has triggered the development of this review. There has been a significant increase worldwide in awareness and concern about the effects of lead on human health and the environment over the last two decades. Both occupational and environmental exposures to lead remain a serious problem in many developing and industrialising countries, as well as in some developed countries. Port Pirie (South Australia) has the world's largest lead smelter and the surrounding population continues to be exposed to environmental lead. The increased awareness of the detrimental impacts of 100 years of smelting at Port Pirie led in 1984 to the development of the Lead Implementation Program, run by the Environmental Health Centre (EHC), Department of Human Services (DHS). The major focus of the program is to reduce household lead exposure for pregnant women and children below the age of five years. Despite intervention efforts by all stakeholders in Port Pirie, 55% of children less than 4 years old have blood lead levels above the National Health and Medical Research Council (NH&MRC) goal of 10 microg/dl. The Port Pirie Lead Implementation Program includes components on nutrition education aimed at reducing lead absorption and toxicity. However, nutritional intake and nutritional status of Port Pirie residents, in particular children under five years, has not been evaluated. This review focuses on nutrition as a component of intervention in lead toxicity and it discusses the nutritional concerns in relation to lead exposure. Fortunately most food patterns that reduce susceptibility to lead toxicity are consistent with recommendations for a healthy diet. The relationship between nutritional status and lead uptake and toxicity is most clearly established for irregular food intake (i.e. periods of fasting), marginal calcium ingestion and (subtle) iron deficiency.