Give your bones a break; the how, the why, and the when of calcium in your diet.

Give Your Bones a Break

Every girl or woman, regardless of her age, should plan daily on how best to get adequate calcium into her diet. Why? Because otherwise she could get the common "brittle bone disease" called osteoporosis.

Evidence suggests that osteoporosis can be prevented by adequate calcium in the diet and through exercise. According to Dr. Walter Merth of the United States Department of Agriculture in Beltsville, Maryland, "right now, calcium is in." Enough calcium on a daily basis is ealy in life may reduce the chance of osteoporosis later in life.

Calcium plays an important part in the daily regimen of millions of women in the United States. This widespread interest in calcium dates back to a conference of experts convened by the National Institutes of Health in April 1984. That prestigious panel issued a statement listing calcium and the female hormone estrogen as the "mainstays of prevention and management of osteoporosis." Since then a plethora of calcium supplements has inundated the market. They not only come in the form of pills, but many food companies are finding ways to add extra calcium to foods such as orange and grapefruit juice, flour, cereals, and yes, even milk.

What is osteoporosis? What is this disease that has triggered so much attention and chaos? And who is affected by it? in osteoporisis there is a decrease in the density of bone mass, resulting in porous bones, sometimes referred to as "brittle bones." The bone loss occurs throughout the skeletal system. The condition afflicts as many as 20 million Americans, mostly women over age 45. It leads to approximately 1.3 million bone fractures each year.

Many tend to think of bone as something unchangeable. The truth is that bone is alive, along with the rest of the body. Each day small amounts of new bone are added and old bone is removed by a process best described by the term remodeling.

The body uses phosphorus, protein, and vitamins A, D, and C to form bone tissue, but calcium is by far the most important nutrient, giving bone its strength and hardness. The bones and teeth contain 99 percent of the calcium present in the body. The other 1 percent is used by the heart to beat, by the muscles to operate smoothly, by the blood to clot properly, and by the nerves to transmit impulses.

Calcium is a mineral and cannot be made from other nutrients, neither can it be manufactured by the body. The body is dependent on the food eaten to supply it. If calcium food are not supplied on a continuous basis, the body takes what it needs out of the bones and puts it into the bloodstream so that the body can function properly. When calcium is removed from the bones continuously and not replaced, the bones become weak and brittle, and the individual becomes a prime target for osteoporisis.

Risk factors. There are several risk factors to be considered in regard to osteoporosis:

1. Sex. Women in general tend to have small and less mineralized bones than men, and tend to lose bone tissue more rapidly. They are subject to eh

stresses of pregnancy, and they are often dieting, which puts them at greater risk.

2. Early menopause, natural or surgical. This occurs in up to 50 percent of the women who have their ovaries removed and have not had estrogen replacement therapy. Hormone levels in women play a role in the maintenance or loss of bone tissue throughout life. Decreased estrogen places women at risk of osteoporosis.

3. Age. As the body ages, the bones decrease in density and weaken, so that the elderly are at a greater risk for osteoporosis.

4. Race. Osteoporosis occurs most frequently in Whites and Orientals.

5. Frame size. This is often owing to heredity. Small-bones people are at greater risk.

6. Smoking. Smoking has been proved to decrease calcium absorption.

7. Alcohol. Alcohol displaces the more nutritious food in the diet, which often leads to malnutrition and impaired calcium absorption.

8. Exercise. People who are inactive, confined to bed, or otherwise immobilized for extended periods of time pose a greater risk for osteoporosis. Weight-bearing exercise, such as walking, lifting, running, bicycling, rowing, and jumping rope, helps to maintain bone mineral content.

9. STress. during times of tension, grief, anxiety, and illness the body absorbs less calcium from the food that is eaten.

10. Diet. A diet that provides low levels of calcium over a period of time is perhaps the most imposing risk factor, since indeed "we are what we eat." One cannot, however, totally overlook other dietary factors that affect calcium retention in the body. High fat intakes interfere with calcium absorption, especially in older adults. Excessive protein tends to increase the urinary loss of calcium, and excessive amounts of fiber cause food to pass through the intestine at a faster rate and/or be affected by phytates in cereal fiber. This in turn limits absorption.

What are the symptoms of osteoporosis? The earliest symptoms of osteoporosis are silent and painless. Gradually and without discomfort, the bones thin out until some of them break, causing pain and disability. Severe low back pain and skeletal fractures are often the primary symptoms.

Visible symptoms may manifest themselves in the loss of height, the outward curvature of the spine called "dowager's hump," and the inward curvature of the lower spine. One may also lose jawbone that supports the teeth, resulting in tooth loss and dentures that never fit properly.

Prevention. The old adage "an ounce of prevention is worth a pound of cure" is most applicable in the case of osteoporosis. Indeed, the only rational approach to osteoporosis is that of prevention. Treatment for osteoporosis should be focused on maintaining bone mass, or at least on slowing down the rate of bone loss. Bones already weakened by osteoporosis cannot be restored to previous strength. Managing the diet early in life and continuing throughout life will help measurably to prevent the loss of bone tissue.

Dr. Charles W. Chestnut III, professor of medicine and radiology at the University of Washington, in speaking to a group of food writers at the Dairy Council of California's fifteenth annual nutrition conference, stated, "Bone mass at 55 is determined by how much bone mass was developed at skeletal maturity between the ages of 12 and 15." Actually, 45 percent of skeletal mass is formed during adolescence. While most preteen children are urged to drink more milk at home and at school and get a pretty good intake of calcium, the level of intake tends to drop during the teenage years when it is needed the most.

The recommended daily allowance of calcium for children ages 1 to 10 is 800 milligrams. This increases to 1,200 milligrams for teenagers between ages 11 and 18 to accommodate the rapid spurts of growth that occur. The recommended calcium for a woman above age 18 has been 800 milligrams, but as a result of the recent findings it has been suggested that women get up to 1,000 milligrams daily before the menopause and 1,300 to 1,500 after menopause if they don't take estrogen. Unfortunately, in reality the average U.S. woman 45 years of age and over consumes only 450 to 550 milligrams of calcium daily.

Food sources of calcium. It is always best to obtain the nutrients we need from food, and calcium is no exception. Milk and other dairy products are the outstanding sources of calcium in the American diet. Without them, satisfactory intake of calcium is extremely difficult. Whole or skimmed milk (sweet or sour), plain or chocolate milk, are all equally good. For the adult, two to three cups daily; and for children and teens, three to four cups daily will ensure adequate intake.

People who have trouble digesting lactose (milk-sugar) can turn to fermented milk products such as yogurt, buttermilk, or special enzyme-treated products.

A few calcium-fortified soy milk products are also available to those who prefer not to drink milk. Tofu, a soybean curd that is now often found in or near the dairy case, is also an excellent source of calcium when made with calcium sulfate or calcium chloride.

Certain leafy green vegetables such as collards, kale, turnip and mustard greens, broccoli, bok choy, and watercress are important sources of calcium when they are eaten liberally and frequently. The calcium from these greens is more readily available to the body than that from some of the more popular ones, such as spinach and chard.

If enough calcium cannot be gotten from the diet, it would be wise to consult a physician concerning the amount of supplement best suited to your needs. When selecting a supplement be sure to read the label. You may want to avoid supplements containing oyster shell, bone meal, or dolomite, which possibly can contain lead.

Other considerations. While calcium intake is most important, a good weight-bearing exercise program is invaluable in stimulating the maintenance and building of new bone. Discuss the possibility ofestrogen replacement therapy after menopause with your physician. Reduce risk factors by avoiding alcohol, smoking, caffeine, and undue stress. If you are frail and elderly, or know someone who is, take safety precautions to prevent falls. An important fact to remember is that men need calcium also. Though not at as high risk as women, they too can get osteoporosis. For recipes highlighting calcium-rich foods, see the article on page 22.

M. Beth McCalla, R.D., is a research dietitian for Loma Linda Foods.