Sodium and potassium in composite food samples from the Canadian Total Diet Study

Sodium (Na) and potassium (K) are essential nutrients. Like people in many Western societies, Canadians consume too much Na and not enough K, both of which contribute to hypertension. We analysed the Na and K content of 154 food composites, broadly representative of the foods most commonly consumed in Canada, from the Canadian Total Diet Study collection of 2007. Foods were prepared as if for home consumption before compositing. No salt was added during food preparation. Samples prepared by aqueous extraction were analysed by atomic emission (Na) or atomic absorption spectrometry (K). Processed foods and soups contained large amounts of Na per reference amount (serving) of the food, with 17 samples containing over 1/3 of the Adequate Intake (AI) for adults, or >500 mg Na/serving. Fluid milk, unprocessed meats and several fruits and vegetables contained large amounts of K per reference amount, with 11 samples containing over 10% of the AI for adults, or >470 mg K/serving. Na:K molar ratios were typically either high or low, with few values near unity. Thus, with few exceptions, foods high in Na were lower in K, and vice versa. Through judicious food selection it may be possible for consumers to decrease Na intake while increasing K, with associated health benefits. Such choices would be consistent with common nutrition advice to decrease consumption of processed foods, while increasing intakes of fresh fruits and vegetables.