Dear Concerned,

Osteoporosis doesn't happen overnight. Many interrelated factors cause this serious loss of bone mass. It begins with osteopenia, a demineralization of bone, and progressively gets worse. But prevention is possible, with proper care.

Diet and other health practices influence our lifetime bone strength. Getting enough calcium, vitamin D, and weight-bearing exercise are part of the prevention picture. According to the new DRI (Daily Reference Intake), we need:

Calcium (No differences for women who are pregnant or lactating)

• 9 - 18 years: 1300 mg/day
• 19 - 50 years: 1000 mg/day
• older than 50 years: 1200 mg/day

Vitamin D

• 9 - 50 years: 5 micrograms [200 International Units (I.U.)]
• over age 50 years: 10 micrograms (400 I.U.)

Weight Bearing Exercise

This part confuses many people. The National Osteoporosis Foundation defines it as "exercise in which bones and muscles work against gravity as the feet and legs bear the body's weight." Examples include walking, jogging, stairclimbing, dancing, and racquet sports, along with weight training. Overexercising, however, can actually decrease bone density. For women, loss of menses may be a signal of too much physical activity.

Other nutrients involved in building strong bones include:

The following weaken bones:

Salt
Sodium is one of the most harmful substances to bone — especially in a low calcium diet. Keep sodium intake below 2400 mg per day.

Caffeine
In the absence of sufficient calcium, even moderate amounts of coffee (16 oz./day) are associated with decreased bone density. Heavy caffeine consumption is known to leach calcium from bones.

Soft drinks
High in phosphoric acid, diets high in soda consumption and low in calcium lead to reduced bone density. Many teens (and adults) substitute sodas for milk — a double whammy against strong bone development and maintenance.

Alcohol
Heavy drinking contributes to bone loss and fractures.

Protein
Excess animal protein increases calcium loss in urine. This is a significant danger in the "high protein diets" popular today. The claim that dairy products increase calcium excretion is simply not accurate. As a matter of fact, calcium from dairy products is associated with stronger bones than calcium from other sources, according to an article published in the American Journal of Clinical Nutrition (1999, vol. 69, pp.727 - 36).

Vitamin A
An excess (in the form of retinol) is dangerous. If you take a supplement or multivitamin, be sure it has no more than 100 percent of the Daily Value (DV) — 1,000 retinol equivalents for men, 800 for women. A good portion of that should be in the form of beta-carotene, which is converted to vitamin A only as the body needs it.

Smoking
Smoking decreases levels of vitamin C and estrogen, both of which are crucial for strong bones. It may also decrease body mass and increase rate of fractures.

Amenorrhea
Amenorrhea means missing your period for three months or more (if you're not pregnant), which may signify a problem that greatly affects your bones. In this case, your body may not be producing adequate estrogen, which is crucial for assimilating calcium into bone. Exercise induced amenorrhea (overexercising to the point of losing one's period) can increase the chance of bone fracture.

Calorie restriction
Chronic dieting, especially when accompanied by amenorrhea, is particularly harmful to bones. Hormonal changes occur, negatively affecting bone formation, in those who severely restrict calories and have poor nutritional intakes.

Low body weight
Yes, you can be too thin! Low body weight provides little to no resistance against your movements. This prevents bones from becoming strong.

Medications
For instance, one of the most well known medications, prednisone, can increase calcium loss. Whenever medication is prescribed to you, check with your health care provider and/or a pharmacist about its effect on calcium loss.

Now that you've boned up on osteoporosis, you can see that eating a well-rounded diet is really the best defense. Although calcium is in the forefront, many nutrients play supporting roles. In addition, regular but not excessive exercise, along with other healthy lifestyle choices, can help you build strong, long-lasting bones.

Alice

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