New data on the bioavailability of bread magnesium.

Whole cereal products are the main source of magnesium in human nutrition. Even if wholemeal bread is an important source of Mg, it also contains considerable amounts of phytic acid (PA), a natural chelator that lowers the absorption of trace elements such as Fe or Zn as well as Ca or Mg in cereal products. Significant Mg bioavailability improvement in bread could be supplied by the choice of raw materials and the baking processes of cereals. Improvement in the Mg content of wheat grain was proved possible by traditional plant selection. Bread making using sourdough improves the nutritional properties of bread by reducing the amounts of phytic acid and phytate breakdown, which is mainly explained by the acidity level in the sourdough process that promotes greater efficiency in the wheat phytase activity. A slight acidification due to sourdough effectively reduces the phytate content and improves Mg bioavaibility.