Calcium recommended daily intake

The main sources of vitamin C are green vegetables and citrus fruit. Animal tissue contains vitamin C, mainly in the kidneys and liver. The level of vitamin C in food is rapidly reduced during cooking or storage due to oxidation or water dissolution. It is added to food as an antioxidant (with no specified limit on the level of use) or as a supplement (with a maximum recommended daily intake of 3000mg/day). The forms admitted are L-ascorbic acid (AA), L-ascorbyl 6-palmitate, sodium, calcium, or potassium L-ascorbate [403]. 

The primary roles and the recommended daily intake of major and trace minerals are listed in Table 38-3. Similar to vitamins, these minerals are typically obtained from dietary sources. Specific minerals may likewise be included in various multivitamins and other dietary supplements, with the intent that these minerals will promote good health and prevent disease. Again, there is generally no need for mineral supplements for most people eating a reasonably balanced diet. On the other hand, mineral supplements can be helpful in specific situations where the body s need for a mineral may exceed dietary supply. Some examples of appropriate supplementation include calcium supplements for people with osteoporosis (see Chapter 31), potassium supplements for people on diuretics (see Chapter 21), and iron supplements for people with certain anemias. Hence, mineral supplements may be helpful in certain individuals, but the dose and type of supplement should be adjusted carefully. 

The recommended daily dietary intake of magnesium is 50-70 mg for children under 1 year, 150-200 mg for children under 6 years, 350 mg for adult men and 300 mg for adult women. During pregnancy and lactation, the daily dose of magnesium should be increased to 450 mg. The recommended daily intake is 400-500 mg of calcium for children under 1 year, 800-1200 mg for older children and adolescents, 800 mg for adults and 1200 mg for pregnant and lactating women. 

For certain vitamins and minerals there are indications that an intake beyond the recommended daily intake required to prevent deficiencies may be beneficial for the prevention of certain diseases. For instance, it has been established that increased intake of folic acid during pregnancy can reduce the incidence of neural tube defects in the newborn. There is also evidence to suggest that the risk of developing cardiovascular disease may be decreased by increasing vitamin E and folic acid intakes, but this remains to be firmly estabhshed. Calcium-enriched products are also believed to have a role to play in bone health. These are just a few of the growing number of links being made between vitamins and minerals and disease risk reduchon. 

Tolerance to the diuretic action of caffeine was demonstrated more than 50 years ago and was shown to develop on chronic caffeine intake so that the clinical significance of hypokalemia and calciuria is difficult to evaluate. Although controversial, some epidemiological studies have implicated caffeine in the increased risk for poor calcium retention. For calcium intakes lower than 750 mg per day, increased rate of bone loss and lower bone density were reported. However, it has been suggested that the effect on bone of high caffeine intake requires a genetic predisposition toward osteoporosis. In individuals who ingest calcium recommended daily allowances, there is no evidence of any effect of caffeine on bone status and calcium economy. 

TABLE 53-4. Recommended Daily Calcium and Vitamin D Intake... 

K/DOQI guidelines recommend that elemental calcium from calcium-containing binders should not exceed 1,500 mg/day and the total daily intake from all sources should not exceed 2,000 mg. This may necessitate combination of calcium- and noncalcium-containing products (e.g., sevel-amer HCL, lanthanum carbonate). 

When the recommended daily allowance (RDA) for calcium is not met by the diet is (particularly in women), supplementation in the form of calcium salts is recommended. Calcium salts vary widely in calcium content by weight, calcium gluconate has 9%, calcium lactate has 13%, and calcium carbonate has 40% calcium. Absorption of calcium from salts may vary calcium carbonate is the most poorly absorbed. Bone meal and dolomite are not recommended sources of calcium, since they may contain lead, arsenic, mercury, and other toxic metals. A potential complication of excessive calcium intake is formation of urinary tract stones this risk may be reduced by ample fluid intake. 

In patients with vitamin D deficiency, oral vitamin D 50,000 units daily for 10 days or once weekly for 8 weeks, or 50,000 to 500,000 units intramuscularly is recommended. Serum calcium and 25(OH) vitamin D should be monitored periodically. Once replete, daily intakes of 600 to 1000 units are usually required. In the community or nursing home, vitamin D 100,000 units once per quarter is reasonable. In patients with vitamin D malabsorption (e.g., gluten-sensitive celiac sprue), 25(OH) vitamin D (calcidiol) administration is needed. In patients with severe hepatic or renal disease, calcitriol therapy may be required. This drug requires careful titration and serum calcium and creatinine monitoring because of its hypercalcemic potential and the limited calciuric ability of the dysfunctional kidney. 

CALCIUM ABSORPTION AND EXCRETION In the U.S., -75% of dietary calcium is obtained from milk and dairy products. The recommended adequate daily intake value for calcium is 1300 mg in adolescents, 1000 mg in adults, and 1250-1500 mg in postmenopausal women typical... 

The recommended daily dietary intake of phosphorus is 300-500 mg for children under 1 year, 800 mg for children under 10 years and 1200 mg for adults. These amounts are easily achieved in a normal diet. It is more important to maintain an appropriate ratio of calcium to phosphorus in the diet than the actual realised amount of phosphorus. Meat, poultry and fish (without bones) contain about 15-20 times more phosphorus than calcium eggs, cereals and legumes contain about 2-4 times more phosphorus than calcium. Only milk, cheese, leafy vegetables and bones contain more calcium than phosphorus. 

Fish and shellfish are excellent sources of protein. A 100 g cooked serving of most types of fish and shellfish provides about 18-20g of protein, or about a third of the average daily recommended protein intake. The fish protein is of high quality, containing an abundance of essential amino-acids, and is very digestible by people of all ages. Seafood is also loaded with minerals such as iron, zinc, and calcium. 

Milk is an excellent source of calcium, phosphorus, riboflavin (vitamin B2), thiamine (vitamin Bl) and vitamin B12, and a valuable source of folate, niacin, magnesium and zinc (Food Standards Agency, 2002). In particular, dairy products are an important source of calcium, which is vital for maintaining optimal bone health in humans (Prentice, 2004). The vitamins and minerals it provides are all bioavailable (i.e. available for absorption and use by the body) and thus milk consumption in humans increases the chances of achieving nutritional recommendations for daily vitamins and mineral intake (Bellew et al., 2000). 

Several government surveys reveal that calcium is one nutrient likely to be consumed in less than recommended amounts (i.e., 800 mg RDA for nonpregnant, nonlactating women) by a substantial percentage of Americans, particularly females 12 years of age and older (Car-roll et al. 1983 Heaney et al. 1982 Chinn 1981 USDA, SEA 1980 Radzikowski 1983). As shown in Figures 7.1 and 7.2, daily calcium intake values reported in the Second National Health and Nutrition Examination Survey, 1976-1980 (HANES II), have been plotted as a function of age for males and females, respectively, and are compared to the RDA. Although the RDA is the same for both sexes, it is clear... 

Supplement your diet with calcium, if necessary, to obtain the daily recommended intake. 

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