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higher, however, since the phosphorus supplied by numerous food additives in processed foods is typically not accounted for in tables of food composition (Oenning et al., 1988).

Major contributors of phosphorus are protein-rich foods and cereal grains. About half the food phosphorus in the U.S. diet comes from milk, meat, poultry, and fish. Cereal products contribute about 12%. Diets based heavily on convenience foods may derive 20 to 30% of phosphorus from food additives (Greger and Krystofiak, 1982).

Meats, poultry, and fish, exclusive of bone, contain 15 to 20 times more phosphorus than calcium. There is twice as much phosphorus as calcium in eggs, grains, nuts, dry beans, peas, and lentils. Only milk, natural cheeses, green leafy vegetables, and bone contain more calcium than phosphorus. Cow's milk contains both more calcium and phophorus than does human milk, and the ratios of the elements differ widely. The ratio of calcium to phosphorus in cow's milk is 1.3 to 1 and that in human milk is 2.3 to 1.

The calcium-to-phosphorus ratio in the U.S. diet varies, depending on food consumption patterns. The calcium-to-phosphorus ratio is higher in diets of infants and children than in diets of adults. The average ratio is 1 to 1.8 for adults between 35 to 50 years of age (USDA, 1984), but may be as low as 1 to 4 for those whose diets are low in dairy products and green vegetables.

General Signs of Deficiency

Because almost all foods contain phosphorus, dietary phosphorus deficiency does not usually occur. An exception is small premature infants fed human milk exclusively. Such infants need more phosphorus than is contained in human milk for the rate of bone mineralization required (Von Sydow, 1946). Without additional phosphorus, hypophosphatemic rickets may develop (Rowe et al., 1979).

Serious phosphorus deficiency has been induced in patients receiving aluminum hydroxide as an antacid for prolonged periods (Bloom and Flinchum, 1960; Lotz et al., 1968). Aluminum hydroxide binds phosphorus, making it unavailable for absorption. Phosphorus deficiency results in bone loss and is characterized by weakness, anorexia, malaise, and pain.

Recommended Allowances

Adults, Children, and Pregnant and Lactating Women

The precise requirement for phosphorus is unknown. Previous editions have set the allowance for phosphorus equal to calcium for all ages except

Front Matter (R1-R12)

Summary (1-9)

Definition and Applications (10-23)

Energy (24-38)

Carbohydrates and Fiber (39-43)

Lipids (44-51)

Protein and Amino Acids (52-77)

Fat-Soluble Vitamins (78-114)

Water-Soluble Vitamins (115-173)

Minerals (174-194)

Trace Elements (195-246)

Water and Electrolytes (247-261)

Other Substances in Food (262-272)

Index (273-283)

Summary Tables (284-285)