The thyroid gland secretes calcitonin, which increases bone mineralization, and decreases the rate at which the bone is broken down. Any factors which interfere with, or alter the delicate balance maintained by these body systems are likely to have a negative impact on bone mineralization. A diet high in phytic acid, which is found in the bran of whole grains, is likely to interfere with calcium absorption. This acid binds to a variety of minerals including calcium, to form insoluble salts, called phytates, which are wasted from the body. A diet high in sodium may also interfere with calcium absorption.
Vitamin D is formed by an interaction between the sun's rays, and skin oils.
Without supplementation, we may be at risk of inadequate vitamin D, if we spend most daylight hours inside. As mentioned earlier, this vitamin is a regluating factor in calcium absorption. Circulating levels of vitamin D throughout the year were probably higher in stone age men and women because they were more likely to be exposed to the sun's rays. Treating every elderly lady in northern latitudes with vitamin D tablets is probably not a bad idea. Our sedentary life ways also interfere with mineralizing our bones.