Early-Life Steps To Prevent Osteoporosis
Building bone mass in early life may be the most effective way to prevent osteoporosis in later life. If this opportunity is missed, it probably cannot be made up. Even small increases in bone mass can have a great impact on the risk of fracture. For instance, a 5-percent increase in bone mass can reduce the risk of osteoporotic fracture by 40 percent.
A lifelong habit of drinking milk is associated with increased bone mass. Researchers at the Indiana University School of Medicine in Indianapolis have shown that calcium supplements increase the bone mass in preadolescent children, compared to that in their identical twins who received placebos during a 3-year study.
Getting Enough Calcium
In the American diet, almost 75 percent of dietary calcium comes from dairy products. Few other foods are concentrated sources of absorbable calcium. At Purdue University (West Lafayette, IN) and Creighton University (Omaha, NE), plant foods are being screened for calcium absorption. These include broccoli, bok choy, kale, and tofu made with calcium salts. Calcium is well absorbed from these vegetables and from all dairy products—that is, milk, yogurt, cheese, processed cheese, and their low-fat counterparts. Spinach is a concentrated source of calcium, but this calcium is poorly absorbed because it is complexed with oxalic acid and is therefore indigestible.
Depending on their stage of growth, people need 2 to 5 cups of milk or the calcium equivalent each day. American females more than 12 years old typically consume less calcium than this recommended amount. Calcium intake in American women is 40 to 50 percent below that in men. A 1984 National Institutes of Health consensus-development conference recommended 1,000 mg of calcium per day for premenopausal women and 1,500 mg per day for postmenopausal women. However, 25 percent of American women have an intake below 300 mg per day, which is the amount of calcium in one glass of milk. Calcium supplements are recommended for individuals who cannot get adequate calcium through diet. However, supplements do not contain all the nutrients necessary for building bones, and people often forget to take pills. An alternative source of calcium is the fortified beverages now on the market.
Exercise
Weight-bearing exercise has a positive impact on bone density. An effective exercise program applies weight loading to all parts of the skeleton. For example, the right arm of a right-handed tennis player has a higher bone density than does the left arm. Activities that are exclusively aerobic seem to be the least effective in building peak hone mass. Thus, weight lifters have higher bone density than do swimmers. We do not know if the positive effects of exercise on bone mass are retained when exercise is discontinued.
Fosamax Ostheoporosis
A partial explanation for bone loss in the elderly is the reduction in physical activity with age. The physical work of the average sedentary elderly adult is 30 percent less than that of the average younger adult. If immobilization occurs, bone loss is accelerated; but bone mass can increase when the individual again becomes ambulatory.
The Known and Unknown
Obtaining adequate dietary calcium, exercise, and estrogen-replacement therapy following menopause are three lifestyle choices for maintaining a strong skeleton. The interaction of these factors is not well understood. Nor do we know the residual positive effect after cessation of treatment. Research to determine the best food sources of absorbable calcium and the most effective exercise programs, in combination with education programs on behavior modification, can help reduce the suffering and the canadian pharmacy costs associated with bone loss.