Bone Formation

• Cross section of the bone.
  
  Bones constantly recycle themselves to maintain their strength. Old bone gets absorbed by cells in the body called osteoclasts in a process known as resorption. New bone growth by cells called osteoblasts replenishes the old. The osteoblasts create new bone material to keep the bones strong. Low bone density occurs when resorption happens faster than new bone material can be made. Depending on the degree of bone loss, it could be termed osteopenia or osteoporosis.
  
  

Dietary Causes of Low Bone Density

• Diets high in calcium and vitamin D can prevent low bone density.
  
  Dietary issues can disrupt the rate at which osteoblasts form new bone. Diets low in minerals used by the osteoblasts--vitamin D and calcium--slow the rate of new growth because the osteoblasts do not have enough of the raw materials needed to make more bone material.
  
  Though low bone density often affects older women, all persons can prevent it by having a healthy diet throughout their lives. Bone material continues to increase in density until 25 to 30 years of age. Until then, the osteoclasts move slower than the osteoblasts, but after age 30, the rate of bone loss increases as the pace of the osteoclasts' resorption of bone material also increases. Having more material in the bones by middle age allows a person to increase the time before their bone density becomes so low that osteoporosis can occur. Diets rich in vitamin D and calcium during the bone building younger years ensure healthier bones later in life.
  
  

Hormonal Causes of Low Bone Density

• Women have a higher rate of low bone material than men. Lower weights of women could account for some of this as the more weight a person carries, the denser the body builds the bones to compensate. Estrogen, the sex hormone produced by women until menopause, helps the body to build bone mass. When estrogen levels drop off, the rate at which new bone material occurs slows. Men can also have low bone density, but they develop it at a slower rate since estrogen does not play as crucial a role in building their bone mass.
  
  

Tests for Low Bone Density

• Bone mineral density (BMD) scanner.
  
  Most doctors, if they suspect low bone density, recommend a bone mineral density (BMD) test. The most common of these, the DEXA scan, requires the patient to lie still as two strong X-ray beams measure the density of the bones. Results in a T-score define the degree of bone loss: normal, osteopenia or osteoporosis.