No abstract

odium (Na) intakes are a major focus of public health concern in many countries at the present time. In July 2010, the Health Canada-led Sodium Working Group (SWG) released its strategy report, which emphasized the link of excessive Na intake to hypertension, while acknowledging its role in several other important chronic diseases. 1 Hypertension affects 20% of adults in Canada and another 20% have pre-hypertension. 2 Chronic, progressive hypertension is strongly associated with adverse cardiovascular changes leading to multi-organ damage, morbidity and death. 3 Many people in Western societies consume too much Na and not enough potassium (K), both of which factors contribute to the high prevalence of hypertension in these populations. 4,5 For most adult North Americans, the Adequate Intake (AI) for Na is 1500 mg/d, while the Tolerable Upper Intake Level (UL) for Na is 2300 mg/d; the AI for K is 4700 mg/d for adults. There is no UL for K due to low intakes in North America and its ready excretion given normal kidney function. 6 It has been estimated that if the Na intake of Canadians were decreased by 1840 mg/d, bringing the intakes of adult men into alignment with the AI, the prevalence of hypertension would decrease by 30% and 23,500 cardiovascular disease events per year would be prevented. 7,8 This kind of projection is, to our knowledge, not available for K. However, the effect that increasing K intakes has on reducing hypertension is additive to the effect of decreasing Na intakes, 4 making it relevant to consider the two nutrients together. An important recommendation of the SWG was to lower Na intakes of Canadians through changes in the food supply. Total Diet Studies (TDS) have been promoted by the World Health Organization and Health Canada for monitoring of a wide variety of chemicals in the food supply. 9 In the United States, TDS have long been used to track changes in nutrients including Na and K. 10 The advantage of TDS is that foods that are analyzed are prepared as if for household consumption, rather than being analyzed raw or as purchased. 11 The Canadian Total Diet Study is designed to collect and analyze market samples representing the majority of foods commonly purchased in Canada 9 for sentinel monitoring of changes in the Canadian food supply. The purpose of this study was to create, using direct analysis of Na and K content of Canadian market foods, baseline information on population distributions of Na and K intakes by gender and age categories in the Canadian population. The specific objectives were