Copper and zinc contents of Nigerian foods and estimates of the adult dietary intakes

Concentrations of copper and zinc were determined in 80 Nigerian food items of various classes which were obtained from the markets of Ibadan city. These consisted of leafy and fruity vegetables, tubers, fruits, meats, fish, legumes, cereals, spices, dairy products, sweeteners, fats and oils, confectioneries, canned foods and alcoholic beverages. Copper levels ranged widely from 0.06 to 13.3 mg/kg, while zinc levels ranged from 0.06 to 56.9 mg/kg in various foods. The differences in mean metal levels were found to be significant (P=0.05) among the various food classes. Highest levels of both metals were found to occur in legumes (Cu, 8.3±3.7 mg/kg; Zn, 29±12 mg/kg). The levels of the metals compare well with those which have been obtained in foods from studies elsewhere in the world. The dietary intakes of both metals for the adult population was found to vary with the income groups, with higher intakes being estimated for higher income groups. The estimated weighted average dietary intakes for the entire adult population were calculated to be 2.64 mg Cu/day and 15.8 mg Zn/day.