- Section 1
- Diet, Calcium and Vitamin D
- Section 3
- Medications that Prevent Bone Breakdown
- Monitoring Osteoporosis Treatment Success
MedicineNet interviewed Dr. Michael Truong regarding updates in the management of osteoporosis. Dr. Truong finished his medical school training at the University of California, San Francisco medical school. He then studied at the University of California, Davis for his residency training in Internal Medicine, and his Fellowship training in Diabetes, Endocrinology, and Metabolism. He spent two years performing research at ADRI (Aoki Diabetes Research Institute), and teaching at the University of California, Davis Medical School. He is currently director of the osteoporosis center with the Mission Internal Medicine Group, a multispecialty group serving southern Orange County, California.
Osteoporosis is a bone disorder featuring progressive loss of bone tissue and bone mass leading to weakening of bone. Normal bone tissue is made of protein (called collagen) and calcium salts. The osteoporosis process depletes both the calcium salts and the protein from the bone. The weakened bone is more prone to breakage (fracture), either by cracking or collapsing (compression). In patients with osteoporosis, bone fractures can occur from minor falls or injuries that normally would not cause a bone fracture. Bones that commonly break in patients with osteoporosis include the spine, hips and the wrists.
Even though osteoporosis can affect both men and women, it is most common among postmenopausal women. The female hormone, estrogen, is important for the preservation of bone mass. Inadequate estrogen during menopause causes accelerated bone loss. Without effective prevention, a woman can lose 20%-30% of her bone mass during the first 10 years of menopause. The osteoporosis process can operate silently for decades. These women may not be aware of their weakened bones until suffering a painful fracture.
Over 20 million people have osteoporosis in the United States, and approximately 1.3 million people each year will suffer a bone fracture as a result of osteoporosis. In 1993, the United States incurred an estimated loss of 10 billion dollars due to loss of productivity and health care costs related to osteoporosis.
The goal of osteoporosis treatment is to prevent bone fractures by 1) stopping bone loss, and 2) by increasing bone mass and strength.
The prevention and treatment of osteoporosis involves programs which include a nutritious diet, cessation of cigarette smoking, curtailing of alcohol consumption, regular exercise, adequate intake of calcium and vitamin D, estrogen replacement or raloxifene (Evista) treatment in postmenopausal women, and medications (such as aledronate, etidronate, or calcitonin) that decrease breakdown (resorption) of bone. Medications that decrease bone breakdown or resorption are also called antiresorptive agents
MedicineNet: How important is diet in the prevention and treatment of osteoporosis?
Dr. Truong: Balanced nutrition, adequate calcium and vitamin D intake, regular exercise, and cessation of cigarettes are important measures to maintain healthy bones for everybody. This is true for children, men, premenopausal and postmenopausal women, and the elderly, regardless of presence or absence of osteoporosis.
Conversely, malnutrition, such as found in patients with anorexia nervosa, contributes to osteoporosis.
MedicineNet: Why is adequate calcium intake important in osteoporosis prevention and treatment?
Dr. Truong: Calcium is an essential nutrient necessary for the proper functioning of the heart, muscles, nerves, and other body functions, as well as maintaining strong bones. Adequate calcium intake is important for everyone, regardless whether she/he already has osteoporosis.
Each day, the body loses calcium in the urine, feces, and sweat. These losses have to be replaced by calcium in the diet. If calcium in the diet is not sufficient to cover these losses, the body takes calcium from the bones. Over time, insufficient calcium in the diet leads to negative calcium balance and bone loss (osteoporosis). Adequate calcium intake can help prevent osteoporosis and increase bone mass and strength.
MedicineNet: How much calcium intake is necessary to prevent and treat osteoporosis?
Dr. Truong: The levels of calcium intake recommended by The National Institutes of Health Consensus Conference on Osteoporosis are:
- 800 mg/day for children ages 1-10
- 1000 mg/day for men, premenopausal women, and postmenopausal women also taking estrogen
- 1200 mg/day for teenagers and young adults ages 11- 24
- 1500 mg/day for post menopausal women not taking estrogen
- 1200mg-1500 mg/day for pregnant and nursing mothers
These recommended levels of calcium intake are meant for all people, not just for those with established osteoporosis. Unfortunately, I am afraid that Americans overall are not taking in enough calcium. Surveys have shown that the average woman in the United States receives less than 500 milligrams of calcium per day in her diet.
MedicineNet: How can a woman tell whether she/he
has enough calcium in the diet? How do you decide who needs
Dr. Truong: You can roughly calculate the amount of daily calcium intake by the following method:
- Excluding dairy products, the average American diet contains approximately 250 mg of calcium.
- There is approximately 300 mg of calcium in an 8-ounce glass of milk or yogurt, or 16 ounces of cottage cheese.
- A person on an average American diet who also drinks one glass (8 ounces) of milk will receive an estimated 550 mg of calcium.
- A person on an average American diet who drinks two glasses of milk (or one glass of milk and 16 ounces of cottage cheese) will receive 850 mg of calcium.
If your calcium intake does not meet the recommended calcium requirements, you can make up the difference either by consuming more dairy products and other calcium rich foods, or by taking calcium supplements. Doctors usually recommend calcium supplements rather than increasing consumption of dairy products. Calcium supplements are easy to use, and calcium from supplements is usually absorbed as well as calcium from milk. Calcium supplements have no calories!
MedicineNet: What calcium supplements do you recommend? How much should one take? What is the best way to take calcium supplements?
Dr. Truong: The most practical and inexpensive form of calcium supplement is calcium carbonate (such as Os-Cal or TUMS) taken with meals. Calcium carbonate is most reliably absorbed if taken with meals.
Daily calcium requirement refers to the amount of elemental calcium consumed. Different calcium salts in calcium supplements contain different amounts of elemental calcium (the actual amount of calcium in the supplement). For example, Os-Cal and Tums are calcium carbonate salts. Each 1250 mg of calcium carbonate salt tablet (such as Os-Cal 500 mg or Tums 500 mg extra strength) contains 500 mg of elemental calcium. A person who needs 1000 mg/day of calcium supplement can take one tablet of Tums 500 mg extra strength (containing 500 mg of elemental calcium) twice daily with meals.
The calcium supplements are best taken in small divided doses with meals. The intestines may not be able to reliably absorb more than 500 mg of calcium all at once. Therefore, the best way to take 1000 mg of a calcium supplement is to divide it in two doses, 1500 mg in three doses.
If constipation and stomach upset occur with calcium carbonate, alternative supplements such as calcium phosphate and calcium citrate (Citracal) can be used.
MedicineNet: What are the side effects of calcium supplements? Are there any issues or concerns patients taking calcium supplements should be aware of?
Many natural calcium carbonate preparations, such as oyster shells or bone meal, may contain high levels of lead, and probably should not be used.
The total daily intake of calcium should not exceed 2000 mg.
In a 12 year Nurses' Health Study involving 90,000 women, high calcium in diet actually lowers the risk of kidney stones. But taking calcium supplements increases slightly the risk of kidney stones. Scientists believe that taking supplements with meals rather than on an empty stomach may reduce kidney stone risk from calcium supplements.
Most importantly, high dietary calcium intake or taking calcium supplements alone is not sufficient in treating osteoporosis, and should not be viewed as an alternative to or substituted for more potent medications such as estrogens or bone anti-resorptive medications in preventing and treating osteoporosis.
Adequate calcium intake and adequate body stores of vitamin D are important foundations for maintaining bone mass and strength. However, they are not as effective as estrogen and antiresorptive medications both in the prevention and the treatment of osteoporosis.
MedicineNet: How important is vitamin D in prevention and treatment of osteoporosis?
Dr. Truong: Vitamin D is important for osteoporosis in several respects:
- Vitamin D stimulates the absorption of our food's calcium from the intestines.
- Lack of vitamin D causes calcium-depleted bone (osteomalacia) that further weakens the bones and increases the risk for broken bones.
- Vitamin D along with adequate calcium (1200 mg of elemental calcium) has been shown in some studies to increase bone mass and decreases fractures in postmenopausal women.
- Furthermore, osteoarthritis (degenerative arthritis) of the knees appears to be worse in patients who are deficient in vitamin D. Patients with osteoarthritis whose body stores of vitamin D are relatively low may benefit from increased vitamin D intake or sunlight exposure.
MedicineNet: Who should receive vitamin D supplementation?
Dr. Truong: Vitamin D comes from the diet and the skin. Skin production of the active form of vitamin D is dependent on exposure to sunlight. Active people living in sunny regions (Southern California, Hawaii, countries around the equator, etc.) can produce most of the vitamin D they need from their skin. Therefore, in Southern California where I have my practice, vitamin D supplementation is mainly used for housebound individuals or nursing home residents. In less temperate regions such as Minnesota, Michigan, and New York, skin production of vitamin D is markedly diminished in the winter months, especially among the elderly. In that population, dietary vitamin D becomes important.
Unfortunately, vitamin D deficiency is quite common in the United States, especially among the elderly living in cold climates. In a study of hospitalized patients in a general medical ward, vitamin D deficiency was detected in 57% of the patients. An estimated 50% of elderly women consume far less vitamin D in their diet than recommended. Vitamin D deficiency is further worsened in the elderly by the lack of sun exposure. Therefore, vitamin D supplementation is vitally important for the elderly.
The Food and Nutrition Board of the Institute of Medicine recommended as adequate vitamin intake: 200 IU daily for people 19-50 years old, 400 IU daily for those 51-70 years old, and 600 IU daily for those 71 years and older. An average multivitamin tablet contains 400 IU of vitamin D. Therefore, one to two multivitamins a day should provide the recommended amount of vitamin D.
Chronic excessive use of vitamin D, especially above
2000 units/day, can lead to toxic levels of vitamin D and
elevated calcium levels in blood and urine. Since various
dietary supplements may also contain vitamin D, it is
important to review vitamin D content in dietary
supplements before taking additional vitamin D.
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