Our body’s mineral supply is heavily concentrated in the skeletal system, with 99% of calcium being stored in the bone.  In addition to providing structural support and producing blood cells, bone also functions in maintaining pH levels of the blood through its role in calcium homeostasis.

Calcium is an alkaline mineral. When the blood becomes acidic (when pH levels fall), calcium is released from bone to normalize the pH of the blood.  Similarly, when the blood becomes too alkaline (the pH rises), calcium is deposited into bone and other tissues. This is part of the normal process of bone remodeling. However, if calcium is abnormally deposited into the wrong places, it can lead to organ and soft tissue calcification which can disrupt the body’s normal functions.

Hormones also play an important role in maintaining calcium homeostasis. Calcitonin and parathyroid hormone (PTH) oppose each other to regulate calcium levels in the blood. When calcium levels are high, the thyroid gland secretes calcitonin which inhibits osteoclast activity and stimulates calcium deposition into the bones.  Osteoclasts are a type of bone cell that break down bone tissue. Calcitonin also serves to reduce calcium uptake in the kidneys and intestines thereby removing it from the body.  Conversely, when blood calcium levels are low, the parathyroid gland secretes PTH which increases osteoclast activity and aids in calcium resorption from bone. PTH also increases calcium uptake in the kidneys and intestines. It stimulates the kidneys to mobilize vitamin D which aids in increased calcium absorption in the intestines. Vitamin D supplementation can also help with this.

Systemic pH, hormonal function, and Vitamin D are all important co-factors in calcium absorption. Others include hydration, fatty acids, other minerals, and digestion. It’s important to note that almost everyone gets enough calcium in their diet, but many may be missing the cofactors that help the body absorb and utilize it.  Nutritional therapy is useful in helping correct these issues to improve bone health.