Copper, manganese, iron and zinc contents of Nigerian foods and estimates of adult dietary intakes

Abstract

The levels of some microminerals – copper, manganese, iron and zinc – were determined in 605 individual food samples representing 141 different foods across 11 food groups. The samples were collected ‘as consumed’ from ten towns and cities located in Ogun State and Federal Capital Territory, Abuja, Nigeria. They were analysed using flame atomic absorption spectrometry after dry ashing procedure. The levels (mg/100g fresh weight) of these minerals ranged from non-detectable (nd) to 3.00, nd to 3.85, 0.042 to 16.5 and 0.014 to 13.2 for copper, manganese, iron and zinc, respectively in the diverse foods. At the food group level, the mean mineral levels were significantly different (P < 0.05) from one another. The mineral concentration data obtained from most of these foodstuffs are similar to those available in reports from other countries around the world. Using the mainly data obtained from the foods analysed, estimate of the adult mean daily mineral intakes (mg/person/day) were 2.7 ± 1.0, 3.7 ± 1.7, 22.3 ± 7.8 and 8.7 ± 3.4 for copper, manganese, iron and zinc, respectively. These mean intakes are within international recommendations and thus indicate safety of consumers. The data obtained from this study is useful in updating the Nigerian food composition database.