Calcium by Karen Schroeder Kassel, MS, RD, MEd

En Español (Spanish Version)

Calcium is the most prevalent mineral in the human body. About 99% of the body's calcium resides in the bones, and the remaining 1% is dispersed throughout other body fluids and cells.

Functions

Recommended Intake

Age Group (in years)	Adequate Intake
	Females	Males
Birth to 6 months	210 milligrams (mg)	210 mg
7-12 months	270 mg	270 mg
1-3 years	500 mg	500 mg
4-8 years	800 mg	800 mg
9-13 years	1,300 mg	1,300 mg
14-18 years	1,300 mg	1,300 mg
14-18 years—pregnant or lactating	1,300 mg	n/a
19-50 years	1,000 mg	1, 000 mg
19-50 years—pregnant or lactating	1,000 mg	n/a
51 years and older	1,200 mg	1,200 mg

Calcium Deficiency

In childhood, not getting enough calcium may interfere with growth. A severe deficiency may keep children from reaching their potential adult height. Even a mild deficiency over a lifetime can affect bone density and bone loss, which increases the risk for osteoporosis.

If you do not consume enough calcium, your body will draw from the storage in your bones in order to supply enough calcium for its other functions: nerve transmission, muscle contraction, heartbeat, and blood clotting.

Calcium Toxicity

Unless doses exceed 2,500 mg/day, adverse effects for adults are unlikely. Very large doses over a prolonged period of time may cause kidney stones and poor kidney function. Your body may not absorb other minerals, such as iron , magnesium , and zinc , properly. These problems could occur from consuming too much through a calcium supplement, not from milk or other calcium-rich foods. The tolerable upper intake level (UL) is set at 2,500 mg daily from age one through adulthood.

Major Food Sources

Dairy foods—milk, yogurt, and some cheeses—are the best dietary sources of calcium. These foods are also rich in vitamin D, which helps the body absorb calcium.

Food	Serving size	Calcium content (mg)
Yogurt	1 cup	300-400
Milk	1 cup	300-400
Macaroni and cheese, homemade	1 cup	362
Parmesan cheese	1 Tbsp	336
Eggnog, nonalcoholic	1 cup	330
Chocolate milk	1 cup	300
Ricotta cheese	½ cup	300
Powdered milk	¼ cup	290
Cheddar cheese	1 ounce	250
Swiss cheese	1 ounce	250
Provolone cheese	1 ounce	215
Cheese pizza	1/6 frozen pizza	210
Mozzarella cheese	1 ounce	175
American cheese	1 ounce	160
Cottage cheese	1 cup	120
Frozen yogurt, soft serve	½ cup	100
Ice cream	½ cup	80

Absorption of calcium from some other dietary sources is not as great as that from dairy foods. Specifically, dark green vegetables contain oxalates, and grains contain phytates, which can bind with calcium and decrease their absorption.

Read labels on tofu and fortified products to determine specific calcium levels of these foods.

Food	Serving size	Calcium content (mg)
Tofu, regular, processed with calcium	½ cup	435
Calcium-fortified soy milk	1 cup	250-300
Salmon, canned with edible bones	3 ounces	212
Calcium-fortified orange juice	¾ cup	200
Blackstrap molasses	1 Tbsp	172
Pudding, from cook & serve mix	½ cup	150
Dried figs	5 pieces	135
Tofu, regular (processed without calcium)	½ cup	130
Anchovies with edible bones	3 ounces	125
Turnip greens, boiled	½ cup	100
Milk chocolate bar	1.5 ounce	85
Okra, boiled	½ cup	77
Tempeh	½ cup	77
Kale, boiled	½ cup	70
Mustard greens, boiled	½ cup	65
Orange	1 medium	50
Pinto beans	½ cup	45

Health Implications

Bone Health and Osteoporosis Prevention

Calcium is essential to build and maintain strong bones at all stages of life. Bone growth begins at conception, and bones grow longer and wider until well into the 20s. After this type of growth is complete, bones gain in strength and density as they continue to build up to peak bone mass by about age 35. From this point on, as a natural part of the aging process, bones slowly lose mass. Calcium is essential to slow this natural loss and stave off the onset of osteoporosis—a disease in which bones become fragile and more likely to break.

Tips for Increasing Your Calcium Intake

• When making oatmeal or other hot cereal, use milk instead of water.
• Add powdered milk to hot cereal, casseroles, baked goods, and other hot dishes.
• Make your own salad dressing by combining low-fat plain yogurt with herbs.
• Add tofu (processed with calcium) to soups and pasta sauce.
• If you like fish, eat canned fish with bones on crackers or bread.
• For dessert, try low-fat frozen yogurt, ice cream, or pudding.
• In baked goods, replace half of the fat with plain yogurt.

Taking Supplements