Final answer:
Factors such as dietary compounds, magnesium levels, fiber, and calcium intake can affect the bio-availability of calcium. Conversely, amino acids, vitamin D, and an acidic pH can enhance calcium absorption.
Step-by-step explanation:
The bio-availability of calcium can be influenced by several factors. For example, certain dietary compounds such as phytate, oxalate, phosphate, and iron can form insoluble salts with calcium, inhibiting its absorption. High levels of magnesium in the diet and excess fiber can also interfere with calcium absorption. Additionally, the percentage of calcium absorption decreases as its intake increases. On the other hand, the presence of amino acids, vitamin D, and an acidic pH in the diet can enhance calcium absorption.