Dietary Trace Elements and Cardiovascular Diseases;
Metabolic Interactions in Mineral Nutrition; Nutrient Risk Assessment Methodology

This research helps us to better understand the roles of dietary trace element imbalances in the development of cardiovascular diseases. Cardiovascular diseases (CVD) are the number one cause of death in Canada, accounting for 38% of all deaths in 1992 (Heart and Stroke Foundation of Canada, Heart Disease and Stroke in Canada 1995). Imbalances of dietary trace elements such as copper, magnesium and iron have been shown to be associated with the development of risk factors for the development of CVD, including alterations in serum cholesterol and triglyceride levels. Oxidative stresses brought about by imbalances in these or other dietary minerals can exacerbate the development of these diseases. The production of oxidized serum lipids, proteins and lipoproteins resulting from dietary trace element imbalances, and their consequences in the pathogenesis of CVD are being investigated.

Other research in this laboratory investigates metabolic interactions in mineral nutrition. Metabolic interactions between different mineral nutrients, or between minerals and other nutrients, can have profound impacts on metabolism and ultimately upon health. Examples of recent research projects in this area include the influence of elevated intakes of calcium and phosphorus on the metabolism and distribution of trace mineral nutrients (e.g. iron, zinc, copper, manganese), and the effects of copper deficiency on energy metabolism in blood cells.

Personnel from this laboratory have played key roles in the development of nutrient risk assessment methodology at Health Canada. Nutrient Risk Assessment is a four-step risk assessment process that addresses hazard identification as well as the three standard components of risk estimation: hazard characterization, exposure evaluation and risk characterization. As such, it provides a framework for using available information to evaluate a nutrient as a potential hazard, including estimation of the probability of occurrence of adverse health effects at different levels of oral exposure. In the context of policies on the addition of nutrients to foods, the goal of Nutrient Risk Assessment is two-fold: (a) to identify options that permit greater flexibility in addition of these nutrients to foods to optimize nutrient intakes; and (b) to ensure simultaneously that individuals' food consumption patterns do not result in nutrient intake levels that are excessive, imbalanced or potentially hazardous to health. The Hazard Identification and Hazard Characterization steps of the risk assessment for calcium, the first nutrient to be addressed by this process, have been completed.