Calcium intake osteoporosis

Oral calcium has long been used for the treatment of osteoporosis, both in the form of dietary and pharmacological supplements. In patients with calcium deficiency, oral calcium at doses of 1000-1500 mg/day corrects a negative calcium balance and suppresses PTH secretion. Sufficient calcium intake is most important for the acciual of peak bone mass in the young, but is also considered the basis of most anti-osteoporotic regimens. In the elderly, supplementation with oral calcium and vitamin D reduces the risk of hip fracture by about 30 4-0%. 

Some osteoporosis risk factors (see Table 53-1) are non-modifiable, including family history, age, ethnicity, sex, and concomitant disease states. However, certain risk factors for bone loss may be minimized or prevented by early intervention, including smoking, low calcium intake, poor nutrition, inactivity, heavy alcohol use, and vitamin D deficiency. 

Age, calcium intake, hormonal status, exercise and vitamin status have all been implicated in the development of osteoporosis. Estrogen levels represent an important factor in skeletal calcium retention and homeostasis. In therapeutic trials in which post-menopausal women were given daily doses of estrogens, such therapy has been demonstrated to be partially effective in reducing the rate of bone resorption. However, this therapy has the concomitant hazard of endometrial cancer (10). Vitamin D and its hormones have been given considerable attention in the more recent studies. Without adequate dietary and tissue levels of such vitamins, calcium absorption and bone status will be impaired. 

Although much attention has been directed toward the relationship between calcium intake and osteoporosis, little consideration has been given to the possible influence of dietary phosphorus on the development of this disease in either man or animals. In a study designed to determine the optimal concentration of calcium and phosphorus in the diet of adult mice, aging animals were found to undergo a greater loss of bone when the Ca/P ratio was 1 1 than... 

The role of estrogens in the prevention and treatment of osteoporosis has been carefully studied (see Chapter 42). The amount of bone present in the body is maximal in the young active adult in the third decade of life and begins to decline more rapidly in middle age in both men and women. The development of osteoporosis also depends on the amount of bone present at the start of this process, on vitamin D and calcium intake, and on the degree of physical activity. The risk of osteoporosis is highest in smokers who are thin, Caucasian, and inactive and have a low calcium intake and a strong family history of osteoporosis. Depression also is a major risk factor for development of osteoporosis in women. 

Low lactase activity has been suggested as a factor leading to osteoporosis as a result of either reduced calcium intake or reduced calcium absorption. However, results are conflicting and further studies will be necessary to resolve this question (Paige and Bayless 1981). The relationship between irritable bowel syndrome and lactase deficiency is still unclear, but hypolactasia does not appear to be a major problem in patients with this condition (Paige and Bayless 1981). 

Osteoporosis is a disease or metabolic disturbance, particularly in postmenopausal women, that indicates a need for a very high dietary calcium intake. High calcium requirements appear to be related to the very high protein intake of the modem Western diet. A decreased protein intake, as can be obtained on a total vegetarian (vegan) diet, can allow for calcium balance, in a variety of age groups, from one third to one fifth the amount of daily calcium required with a Western diet. 

Calcium needs and metabolism have become an important nutrition issue due to the increased prevalence of osteoporosis. Osteoporosis is a disease of fragility of major bones such as the pelvis, femur, and spine caused by an age-related loss of bone minerals. As discussed in Chapter 7, calcium intake and physical activity may favorably affeot the calcium content of bones and delay the onset of osteoporosis. 

Determination of dietary calcium intake is important to those studying osteoporosis however, an accurate value for Ca intake is often elusive. 

In general, there is an increased risk of nephrolithiasis with prolonged high calcium intake. Studies aimed at determining whether high calcium intake increases the risk of nephrolithiasis have shown that in patients at risk of nephrolithiasis or with a history of nephrohthiasis, calcium can be safely given for osteoporosis, provided there is careful monitoring (10,11). 

There seems to be little reason to suspect that the elderly have a tendency to be deficient, or even marginally deficient, in zinc (Wood et al., 1995). On the other hand, an emerging concern is that increased calcium intake can interfere with zinc absorption or retention (Sandstead and Smith, 1996). A study of postmenopausal women revealed that supplements of zinc plus calcium seemed to prevent bone loss, while supplements of calcium only permitted bone loss (Strause et al, 1994). Hence, there is some interest in the question of whether persons taking calcium, with the possible effect of preventing osteoporosis, should also take zinc supplements. 

High calcium intake in teenage girls Reduced risk of osteoporosis... 

There is accumulating evidence that calcium (Ca) supplementation of the diet may be useful, under certain circumstances, for the prevention of osteoporosis (OP) in postmenopausal women. Calcium intake is an important determinant of bone health. Several chnical trials of calcium supplementation in the prevention and treatment of OP have shown that calcium can decrease the rate of bone loss and risk of fracture in postmenopausal women. This effect is more clearly seen after the first 5 years of menopause, rather than in early menopause. 

When taking fluoride, a relatively new but promising treatment for osteoporosis, the client should maintain an adequate calcium intake. Because the main risk factor for developing osteoporosis is low calcium level, the client should keep taking calcium no matter what medication is prescribed to help prevent or treat osteoporosis. 

Women produce less estrogen after menopause. Estrogen inhibits calcium loss and bone erosion. Reduced estrogen levels result in more rapid calcium and bone loss. Osteoporosis can be minimized if adequate calcium intake occurs, especially from adolescence through young adulthood, and if estrogen replacements are taken after menopause. 

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