Supplementation with fiber-rich multimixtures yields a higher dietary concentration and apparent absorption of minerals in rats

Multimixtures (MMs) are dietary supplements prepared with low-cost ingredients and food by-products that are widely used in various countries to counteract malnutrition. Although MMs have a high content of minerals, they also contain high levels of dietary fiber and associated compounds, which might bind minerals and impair their absorption. In this study, we investigated the hypothesis that the increased dietary fiber content of MMs would impair gastrointestinal mineral absorption due to the metal-binding capacity of dietary fiber. Thus, the objective of the present study was to feed growing rats with a basal diet, representative of a nutritionally deficient diet, alone or supplemented with a low dietary fiber level MM, intermediate dietary fiber level MM, or high dietary fiber level MM (HF) to evaluate the apparent absorption of calcium, phosphorus, magnesium, manganese, and copper. The relative apparent calcium absorption was slightly decreased by the HF addition, with no change in the absolute apparent absorption. The absolute apparent absorption of phosphorus and magnesium was increased by the intermediate dietary fiber level MM and HF additions, whereas the manganese absorption was increased only by the HF addition. The apparent absorption of copper was not affected by the MM supplementation. The increased apparent absorption of minerals was always related to the increase in the mineral dietary concentration triggered by the MM. Thus, we concluded that the increased dietary fiber levels in the MMs increased the mineral levels, and MMs with intermediate and high fiber levels may be used to improve the mineral balance of poor diets.