A system to assess the quality of food sources of calcium

Since the bioavailability of calcium varies greatly among various types of foods, information merely listing the amounts of calcium in foods can be very misleading. Using published values for calcium fractional absorption, a simple two-criteria system is presented and used to assess foods as reasonable calcium sources. For a food to be a good calcium source, two criteria must be met: a standard serving must contain at least 30 mg of absorbable calcium, less than 418 kJ (100 kcal) of the food must provide 30 mg of absorbable calcium. Calcium-containing foods are divided here into good calcium sources (both criteria are met), potential calcium sources (only one criterion is met), and poor calcium sources. Good sources include most milk products, most types of tofu, some dark green leafy cabbage family vegetables, turnip greens and canned fish such as salmon and sardines that include bones. Potential calcium sources include ice cream and most green leafy vegetables. Poor calcium sources include cottage cheese, all beans, some types of tofu, almonds, and sesame seeds. Using this system to identify calcium-rich food sources avoids the misuse of nutrient data when foods are listed simply by their calcium content.