Boning Up on Women's Health

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Boning Up on Women's Health
by: Kathy G. Wise, RD, LD

". . . Of the 25 million Americans afflicted with osteoporosis, a preventable disease, most are women."

Osteoporosis is a disease involving loss of bone material. Most of the body's calcium is stored in the bones, which lose density if this calcium supply dwindles. A diagnosis of osteoporosis means thin, brittle bones that may be easily fractured. Although best known as a disease of elderly women, one form of osteoporosis can also occur in men.

You can maximize bone density and prevent thin weak bones with a nutrient rich diet and exercise. The key to bone health is practicing good nutrition, especially for women from preadolescence through the onset of menopause, in combination with other preventive measures, such as exercise.

Osteoporosis, a preventable disease, leads to more than 1.5 million bone fractures every year, costing the U.S. health care system more than $10 billion. Of the 25 million Americans afflicted with this disease, most are women. The determinants of bone density include factors such as genetics, nutrition, mechanical loading, lifestyle, and overall physical health and medical history. You may not be able to do anything about genetics or your medical history, but you can control other factors such as nutrition, mechanical load and lifestyle.

Nutrition is Your First Defense
Calcium plays the primary role in the prevention and treatment of osteoporosis. A women's greatest bone mass and density (called peak bone mass) is reached when she is between 30 and 40 years old. Prior to this time the best prevention is consuming a calcium and nutrient rich diet. Shortly after peak bone mass is reached, age related bone loss begins at a rate of 1 percent per year in women and continues until menopause. Optimal calcium (1000 - 1200 mg per day) and nutrient intake plus exercise during childbearing years slows this natural bone loss process. After menopause the loss accelerates because of the loss of endogenous estrogen. High calcium intake of 1500 mg per day along with exercise can slow or halt the postmenopausal acceleration of bone loss.

It is never too late to correct a calcium poor diet, although the more progressed the disease the longer it may take to strengthen the bones. In studies on early postmenopausal women, calcium supplementation improved bone mineral content and slowed bone loss in some bones but did not entirely prevent the condition. Women who have consumed calcium poor diets show the greatest improvement in reducing bone loss, whereas women whose diets were optimal in calcium do not show additional benefits when they increase calcium intake.

Beyond Calcium
Other lifestyle factors such as excess sodium, protein, alcohol, and avoidance of weight bearing activities contribute to the development of osteoporosis. A high sodium diet might interfere with calcium retention and increase the risk of developing osteoporosis. Researchers at the National Institute of Health and Nutrition in Tokyo have reported that a high salt diet increases calcium loss in the urine, which could reduce bone density if prolonged.

Excess protein intake also increases calcium loss in the urine, which could also reduce bone density. This is of special concern for those following a high protein weight loss diet.

In contrast other dietary factors, such as lactose in milk, vitamin D, magnesium and zinc increases calcium absorption and helps prevent osteoporosis. Vitamin D plays a major role in both calcium absorption and bone metabolism. Vitamin D is made in the skin in the presence of sunlight or is obtained from food sources - primarily Vitamin D milk. People who have little exposure to the sunlight and do not get adequate vitamin D in the diet may need to consider supplementing their diet with Vitamin D.

Research shows that magnesium affects bone status from conception, and inadequate intake might contribute to the development of osteoporosis. In addition, magnesium, calcium absorption and metabolism are interrelated. Increasing calcium intake without a concurrent increase in magnesium intake can reduce magnesium levels in bone and other tissues. Women on average consume approximately 200 mg of magnesium each day. Some researchers feel this should be increased to 6 to 8 mg per kilogram of body weight.

Other Minerals: Copper, Fluoride, Maganese, and Zinc
Calcium and magnesium work as a team with other minerals in the maintenance of healthy bones.

Inadequate copper intake is associated with calcium loss from the bones, reduced bone formation and bone deformities. Copper is a trace mineral and found in most foods. A safe and adequate intake for copper is 1.5 to 3.0 mg per day. Fluoride supplementation has produced contradictory results. Fluoride strengthens the crystalline structure of bones and teeth, and women who live in areas where the water is fluoridated have a lower incidence of developing osteoporosis. However, other studies have reported that 80mg of fluoride daily increases the risk of hairline fractures in the spine of postmenopausal women with osteoporosis. Maganese is also important in bone growth and metabolism. Maganese is a trace element and easily found in most foods. A safe and adequate intake is 2 to 5 mg per day. A deficiency of this trace mineral increases calcium loss from the bone and the risk of fractures. Finally zinc intake is directly related to bone density. The recommendation for Zinc is 12 mg up to age 50, after age 50 it increases to 15 mg.

What about Calcium Supplements?
Research shows that calcium from food sources is best absorbed. Dark green leafy vegetables are excellent sources of calcium but the mineral is not as well absorbed as it is from milk sources.

Although dietary sources of calcium are preferred, research evidence supports recommending calcium supplementation for women with typically low calcium intake. The form of supplemental calcium that is best absorbed is still under investigation. Most studies have used calcium carbonate, because it is inexpensive, is high in calcium and well tolerated. Most calcium supplements should be taken with food to enhance absorption. Taking a supplement with a dairy source is the best absorbed. Several studies show that people with low stomach acid absorb calcium citrate better than calcium carbonate.

This information is provided for educational purposes only and is not intended as a substitute for professional medical advice. Do not use this information to diagnose or treat a health problem. Please consult your health care provider if you suspect you are ill, or have questions about your condition.