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calcium and bone health The correlation
between dietary intake of calcium and the density
and STRENGTHof the bones. Calcium is essential for
proper BONEstructure, strength, and mass. The
bones contain about 99 percent of the calcium in
the body. From before birth until about age 30,
the body adds calcium and other minerals to bone
tissue to increase bone mass and strengthen the
skeletal structure. The SKELETONreaches peak bone
mass and strength in the late 20s. After age 30,
bone mass begins to decrease. With increasing
age after 30 the body’s ability to absorb dietary
calcium diminishes. Cigarette smoking and long-
term excessive ALCOHOL consumption accelerate
the decrease. It is important for long-term bone
health that peak bone mass be as high as possible.
Regular weight-bearing exercise, such as walking
and running, stimulates the growth of new bone
tissue.

BONES: THE BODY’S CALCIUM BANK

Calcium is a vital mineral for many activities in

cells throughout the body, including the conduc-

tion of NERVEsignals and the contraction of MUS-

CLEcells. The body uses the calcium stores in the

bones to meet its other needs for calcium when

dietary intake does not meet those needs and

calcium in the BLOODcirculation drops. CALCI-

TONINand PARATHYROID HORMONEare the hor-

mones that primarily regulate calcium transport

between the blood circulation and the bones.

Without adequate calcium the bones can
become dangerously thin and weak, making them
susceptible to FRACTUREunder circumstances that
otherwise would not harm the bones. The key
health conditions of inadequate BONE DENSITYare

OSTEOPENIAand OSTEOPOROSIS. Osteoporosis is the

leading cause of HIP FRACTURE IN OLDER ADULTS,

which often results in long-term disability or pre-

mature death. Though loss of bone density with

aging is inevitable, lifelong measures such as ade-

quate calcium intake and daily weight-bearing

exercise can maintain bone health and prevent

osteoporosis.

The body must obtain calcium through dietary

sources or supplements. The amount of calcium

an individual needs changes across the spectrum

of age. The years of ADOLESCENCEare among the

most vulnerable for inadequate calcium consump-

tion because teens tend to drink much less milk

and eat fewer dark green vegetables, the primary

dietary sources of calcium in the American diet.

CALCIUM INTAKE NEEDS

Age Daily Adequate Intake (AI) Amount of

Calcium

birth to 3 years 500 milligrams (mg)

4 to 8 years 800 mg

9 to 18 years 1300 mg

19 to 50 years 1000 mg

51 years and older 1200 mg

Natural dietary sources of calcium include dairy

products (milk, cheese, yogurt), dark leafy vegeta-

bles such as spinach and broccoli, and tree nuts

such as almonds and pecans. Many foods sold in

the United States are calcium-fortified (contain

added calcium). They include orange juice, cere-

als, breads, SOYmilk, and soy products such as

tofu. Low-fat dairy products, which have lower

amounts of saturated fats, are the more healthful

choice and contain just as much calcium as higher

fat products. Labels on packaged foods in the

United States state, per serving, the food’s calcium

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