Calcium, iron and zinc availability from weaning meals

During the weaning period, solid foods are introduced in the diet to complement human milk or infant formula. Consequently, marginal deficiencies may easily develop because of inappropriate feeding and low bioavailability of nutrients. The objective of this study was to determine calcium, iron and zinc availability from weaning foods that contained a variety of ingredients but almost the same dietary fibre content, and to describe dietary factors that influence availability in a linear matter. Availability measurements from eight meals were made in vitro by a continuous-flow dialysis system with preliminary intraluminal digestion. Calcium, iron and zinc were analysed by flame atomic absorption spectrometry; ascorbic acid content was taken from food-composition tables; and macronutrient and mineral contents were obtained from the manufacturer. Calcium availability was higher in fruits (mean +/- SD, 39.2 +/- 4.1%) than vegetables (31.7 +/- 5.8%) (p < or = 0.001). Iron availability was marginally significant higher in vegetables (13.0 +/- 4.7%) than fruits (10.2 +/- 1.6%) (p = 0.027). Zinc availability showed higher availability in fruits (52.3 +/- 22.3%) than vegetables (22.1 +/- 5.6%) (p < or = 0.001).

A major portion (47.8%) of the variance in calcium availability, as determined by multiple regression, could be explained by protein (p = 0.058, beta = -0.691). Major predictors of iron availability among the nutrients were iron content of the meal (p = 0.014, beta = -0.838), carbohydrates (p = 0.044, beta = -0.610) and dietary fibre (p = 0.235, beta = -0.285). Zinc availability was merely influenced by the protein (p = 0.010, beta = -0.876) and fat content of the meals (p = 0.295, beta = 0.255) in relation to other nutrients.