Total and dialyzable levels of manganese from duplicate meals and influence of other nutrients: Estimation of daily dietary intake

Both total and dialyzable Mn levels were determined in 108 duplicate meals during 36 consecutive days. Both mineral fractions were measured by a graphite furnace atomic absorption spectrometry (GFAAS) method previously optimized. A total mean Mn fraction of 1.03 ± 0.49 mg was found in the meals. The Mn supplied by the meals is directly and significantly (p < 0.001) correlated with macronutrient content (carbohydrates, fibre and protein). The mean Mn fraction dialyzed through the dialysis membrane was 0.23 ± 0.17 mg (22.0 ± 8.93% as bioaccessible fraction). The total and dialyzable Mn fractions found for breakfasts were significantly lower (p < 0.001). Nevertheless, the Mn bioavailabilities expressed as the percentage of dialyzable element, were not significantly different among the three primary meals (breakfast, lunch and dinner). A significant correlation between the total and the dialyzable fraction of Mn in meals was found (p < 0.001, r = 0.78, r2 = 0.61). The dialyzed element fractions present in meals were significantly correlated mainly with carbohydrates, protein and several amino acid levels (p < 0.01). Foods with higher carbohydrate and therefore energy contents, e.g. cereals, legumes, vegetables and fruits, would be primary sources of bioaccessible Mn in the diet. The bioaccessibility of Mn was only significant influenced by energy, carbohydrates and Se levels present in meals. The mean Mn daily dietary intake (DDI) was 3.05 ± 0.61 mg day−1.