Question:
What disease affects 1 in 10 Americans (28 million), with healthcare costs of over $14 billion a year? What disease poses a risk for Caucasian women that is equal to their risk for breast, ovarian, and uterine cancers combined? What disease receives relatively little public health attention, despite having reached epidemic proportions in the United States? What disease, despite being one of the most prevalent in America today, is also one of the most preventable?
Answer:
Osteoporosis. Osteoporosis—or “porous bones”—occurs when bone loss outpaces bone formation, resulting in frail bones and an increased risk of fractures. The disease is most common in Caucasian and Asian women over the age of 50. Other groups, such as men and non-Caucasian women, are at a lower, although significant, risk.
Osteoporosis is a “silent” disease, meaning that a person may steadily lose bone mass over many years but remain symptom-free until his or her bones become so weak that they sustain a fracture. For many people, this proves to be a life-threatening event. One in two people who fracture a hip never fully recovers, and one in three-to-four people who fracture a hip dies within a year.
This is disheartening news for an aging American population. Seventy million Americans will turn age 65 by the year 2030, and many of these individuals are at risk for osteoporosis and bone fractures. By then, annual healthcare costs due to osteoporosis in the United States are expected to reach $60 billion. Widespread preventive measures must be taken to improve the bone health of Americans.
Preventing Bone Loss
Many factors contribute to the proper formation and maintenance of bones. These include diet, physical activity, hormone levels, and smoking status, among others. For example, postmenopausal women who undergo hormone replacement therapy (HRT) can stem bone loss and reduce their risk of fractures.
Eating for Strong Bones
A plethora of vitamins, minerals, and other nutrients affect bone health, including calcium, phosphorus, magnesium, fluoride, and vitamins D and K.
Calcium is probably the most well studied nutrient with respect to bone health. The connection between calcium and bone health is a logical one, considering that about 99 percent of the body’s calcium is stored in bone.
Therefore, the evidence is clear: consuming adequate amounts of calcium in the diet is imperative for both young and old individuals. Bone mass accumulates rapidly during adolescence, with 99 percent of bone minerals being deposited by the age of 22. The body comes to rely on this reserve in the later years of life, after bone formation has ceased. Studies have shown that adolescents who have high calcium intakes tend to develop greater bone density.
The same is true for older adults, who retain more bone density and have less bone loss when their calcium intake is high. Calcium is especially important during menopause, when women lose bone mass at a rapid rate. However, the rate of bone mass loss seems to be decreased by calcium supplementation.
Another nutrient important to bone health is phosphorus. Eighty-five percent of phosphorus in the body is found in bone, where it works with calcium to strengthen bones. Both calcium and phosphorus would be ineffective without the help of vitamin D. Therefore, the intake of adequate amounts of vitamin D ensures that calcium and phosphorus are absorbed by the body. Consumption of a combination of calcium and vitamin D seems to be especially effective in promoting bone health in elderly individuals.
There is preliminary evidence that fluoride, magnesium, and vitamin K also play roles in maintaining bone integrity. Scientific studies with these nutrients are under way to determine exactly how and to what extent they are involved in bone health.
In the meantime, it is wise to include all of these nutrients in a well-balanced eating plan. Refer to the chart on page 3 for foods that are good sources of these nutrients. Also, keep in mind that the Dietary Guidelines for Americans and the Food Guide Pyramid outline an eating pattern that are beneficial to bone health.
Testing Theories:
It has been shown that caffeine consumption causes a slight and temporary rise in the level of excretion of calcium (reversed within a few hours), leading to speculation that the use of caffeine could compromise bone health. The results of scientific studies in this area have failed to confirm this theory, although it has been found that individuals who have low calcium intakes have increased bone loss. The bottom line is that a person’s bone health should not be affected as long as calcium intake is adequate.
It has been hypothesized that consumption of soft drinks may indirectly compromise bone health status by displacing calcium-rich beverages, such as milk, from the diet. However, the research surrounding this “displacement theory” is not definitive. Soft drinks can be enjoyed in moderation as part of a bone-healthy diet, as long as bone-building nutrient requirements are also met.
The Benefits of Activity
There is no denying the fact that physical activity leads to better health. Physical activity has proved beneficial in reducing the risk of chronic diseases such as heart disease, cancer, diabetes, and obesity. The results of numerous studies strongly suggest that bone health is no exception.
Vigorous activities such as weight lifting, aerobics, tennis, dance, walking, and running help build bone mass and slow bone loss throughout the life cycle. These activities also enhance muscle strength and improve coordination, which help reduce the risk of fall-related bone fractures.
Some studies suggest, however, that physical activity need not be vigorous to improve bone health. People who regularly engage in lower-intensity movement, such as gardening and leisurely walking, have been shown to reap the benefits of stronger bones. On the flip side, those who are considered sedentary (those who sit at least nine hours per day) have been shown to be at greater risk for a hip fracture.
There is no question that regular physical activity improves bone health; the only questions are how much? how often? and for how long? Researchers are working to answer those questions, but for now, consumers should continue enjoying an active lifestyle to build and keep strong bones.
| Major sources of “Bone-Building” nutrients |
| NUTRIENT |
MAJOR SOURCES |
| Calcium |
Dairy products (milk, yogurt, cheese), green leafy vegetables (kale, collards, broccoli), fortified orange juice, tofu (set in calcium). |
| Phosphorous |
Meat, poultry, fish, eggs, milk products, nuts, legumes. |
| Magnesium |
Seeds, nuts, legumes, dark green vegetables. |
| Fluoride |
Fluoridated drinking water, foods prepared with fluoridated water. |
| Vitamin D |
Fortified milk, fatty fish (salmon, herring), exposure of skin to sunlight. |
| Vitamin K |
Leafy green vegetables, (spinach, kale, broccoli, dark lettuce), margarine, plant oils. |
For More Information on Bone Health and Osteoporosis
National Institutes of Health: Osteoporosis and Related Bone Diseases National Resource Center: http://www.osteo.org
National Osteoporosis Foundation: http://www.nof.org
USDA Center for Nutrition Policy and Promotion (Food Guide Pyramid and Dietary Guidelines): http://www.usda.gov/cnpp
International Food Information Council Foundation: http://ific.org
