Iron Bioavailability of the diets of Canadians

Dietary iron is found in heme and non‐heme forms, with heme iron, primarily from meat, fish and poultry (MFP), absorbed in relatively high amounts; while non‐heme iron from non‐meat and food fortificant sources is absorbed at relatively low levels. Non‐heme absorption can be increased by enhancers such as ascorbic acid and MFP when they are consumed at the same time. Our objective was to estimate food iron bioavailability of the mixed Canadian diet, using > 35,000 food intake records from the Canadian Community Health Survey (CCHS 2.2‐Nutrition) conducted in 2004. Heme values were abstracted from the literature for all single ingredient foods containing MFP (or imputed from comparable literature values) and calculated for food recipes containing MFP. Food records were grouped by eating occasion for each individual and bioavailable iron calculated by applying the Monsen equations for each eating occasion. Total bioavailable iron was calculated as the sum of absorbable heme iron and non‐heme iron sources. Mean adult total iron intakes were 14.02 mg/d (8.96–17.29 for the lowest and highest quartiles respectively). Mean total absorbable iron was 0.88 mg/d (0.46 to 1.15 mg/day for the lowest and highest quartiles). These results indicate that the iron bioavailability of the typical North American diet is less than the 18% that was assumed during the establishment of the Dietary Reference Intakes (DRIs) for iron. Funding – Beef Information Centre