What prevents the full intake of calcium in milk?

Phosphorous: Also known as phosphoric acid and phosphate, phosphorous, which is in cola and many processed foods, can interfere with calcium absorption.

Insoluble fiber: This type of fiber, such as the kind in wheat bran, reduces calcium absorption

Foods with high levels of oxalic acid include spinach, collard greens, sweet potatoes, rhubarb, and beans and this will interfere with calcium absorption.