Bone constantly reforms. Old bone is broken down while new bone is made but in people with osteoporosis, more bone is broken down than built. This results in bone that is not dense enough and because of this, the bones can easily fracture. Getting the proper dosage of calcium and vitamin D can lower the risk for developing this disease.
What is Osteoporosis?
People with osteoporosis have weak bones, and this can result in fractures with only a small amount of trauma. Most fractures take place in the hips, wrist and spine, and several fractures in the spine can result in a "hump back." Indeed, approximately 25 million American women have osteoporosis, with eight million fractures as a result, according to Jeannette South-Paul, M.D., Chair of the Department of Family Medicine at the University of Pittsburgh School of Medicine in "Current Diagnosis & Treatment in Family Medicine."
Development of Osteoporosis
Osteoclasts are the bone cells that break down old bone. They will break down a small area of bone and then leave. Soon, the osteoblasts will arrive. These bone cells put new bone in the area where the osteoclasts just left. Vitamin D, estrogen, calcitonin, prostaglandins, cytokines and the parathyroid hormone regulate this whole process, writes Lawrence Raisz, M.D., Director of the University of Connecticut Center for Osteoporosis in "The Merck Manual for Healthcare Professionals." When a person has osteoporosis, since more bone is broken down than built, the bone is not dense enough.
Risk Factors
Dr. Raisz explains in "The Merck Manual for Healthcare Professionals" that people reach their highest bone density in their mid-20s. It stays at that level for approximately 10 years, then they lose an estimated 0.3 to 0.5 percent of bone every year, because more bone is broken down than built. At menopause, women lose three to five percent of bone every year for approximately five to seven years. The risk factors include being thin, eating high-protein diets, and not having enough calcium and vitamin D. Consuming an excessive amount of alcohol and caffeine, and smoking cigarettes are all risk factors as well.
Parathyroid Hormone, Calcium and Vitamin D
The thyroid gland releases the calcitonin hormone to lower levels of calcium in the bloodstream, while the parathyroid gland releases the parathyroid hormone to increase calcium levels. As explained in the "Handbook of Pathophysiology" by Elizabeth Corwin, Ph.D., the parathyroid hormone tells the osteoclasts to increase their breakdown of bone. This releases calcium from the bone, which goes into the bloodstream. The parathyroid hormone also gives instructions to the kidneys, telling them to make the active form of vitamin D. Vitamin D increases the absorption of calcium and phosphate in the small intestines, which then increases the calcium and phosphate levels in the blood.
Calcium and Vitamin D Dosage
According to the University of Maryland Medical Center, getting enough calcium and vitamin D lowers the risk of developing osteoporosis. The food sources of calcium include salmon and sardines with the bones, broccoli, kale, collard greens, yogurt, milk, cheese and soy milk. There is vitamin D in liver, egg yolks, tuna fish, mackerel, salmon, soy milk and milk. The National Institutes of Health recommends that people between the ages of 19 to 50 years old consume 1,000 mg of calcium and 400 to 800 IU of vitamin D each day. People older than 50 years old should consume 1,200 mg of calcium and 800 to 1,000 IU of vitamin D every day.
References
- "Current Diagnosis & Treatment in Family Medicine"; Jeannette South-Paul, M.D., Samuel Matheny, M.D., Evelyn Lewis, M.D.; 2008
- "Handbook of Pathophysiology"; Elizabeth Corwin, MSN, Ph.D., FNP; 2000
- National Institutes of Health: Calcium
- The Merck Manual for Healthcare Professionals: Osteoporosis
- University of Maryland Medical Center: Osteoporosis -- Lifestyle Changes
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