Breakfast cereal is a regular component of daily diets in Poland and in other countries. Since these products are very popular components of diets, they should be a source of key nutrients, including minerals. The objective of the study was: 1) to determine how popular cereals were among young and pre-teen school children; 2)  to verify whether cereals could be a source of sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg). 232 ready-to-eat products were tested. The content of Na, K, Ca and Mg was determined using flame atomic absorption spectrometry in a Varian SpectrAA 280 FS. Daily intake of Na, K, Ca and Mg by children (aged 7 - 12 years) from 1 serving of breakfast cereals (1 serving size = 30g cereal + 125 ml milk) was compared with AI (for Na and K) or RDA (for Ca and Mg). The highest content of Na was recorded in cornflakes (approx. 500 mg/100 g), K in bran (more than 250 mg/100 g), Ca in bran and wholegrain cereals (approx. 57 mg/100 g), Mg in bran (nearly 180 mg/100 g). It was found that although cereals were not a rich source of Na, K, Ca and Mg for the studied group of consumers, when prepared with milk their nutritional value was significantly enhanced. One serving of breakfast cereals with milk per day would cover 5 – 17% of AI for Na, 5 - 7% of AI for K , 12 – 17% of RDA for Ca and 10 – 57% of RDA for Mg. Cornflakes, which turned out to be the richest source of Na, were the least valuable in terms of the content of the macroelements, in which they resembled rice flakes. All breakfast cereals, while not being particularly rich in Na, K, Ca and Mg, when prepared with milk have a considerably better value for school-age children and ensure a higher consumption of milk.

21.2.2016