Calcium is a naturally occurring mineral that is needed by the body to build and maintain strong bones and teeth. Because calcium is not made in the body, it must be absorbed from a person's dietary intake. Calcium is shed from the body in skin, nails, hair, sweat, urine, and feces. When a person does not get enough calcium through their diet, the body must break down bone to obtain the mineral.

Throughout life, bones go through a process known as remodeling, in which small amounts of old bone are removed and new bone is formed in its place. Generally, after age 35, more bone is lost than gained. Bone loss accelerates after menopause.

Women are vulnerable to osteoporosis, or a thinning of the bones, which develops slowly over many years. Researchers believe that decreasing hormone levels, too little calcium in the diet early in life, and lack of exercise play a role in osteoporosis.

Calcium can be obtained from a variety of foods. Milk and dairy products are the biggest sources of calcium. Green leafy vegetables are another source of calcium. Therefore, eating a balanced diet with a variety of foods is very important.

The National Academy of Sciences' Institute of Medicine has issued daily calcium and vitamin D intake guidelines for various groups of persons.

Selecting foods high in calcium is one way to help you achieve your targeted daily calcium intake. Here are 25 major food sources of calcium to assist your meal planning.

Serving Size	Food	Amount of Calcium (mg)
1 cup (8 oz)	Yogurt, plain, low-fat	415
1 cup	Yogurt, fruit, low-fat	314
1 cup	Skim milk	302
1 cup	2% milk	297
1 cup	Whole milk	291
1 oz	Swiss cheese	272
1 oz	Cheddar cheese	204
1 oz	Colby cheese	194
1 oz	American cheese	174
1 cup	Cottage cheese, low-fat	155
1	English muffin, with butter	103
1 cup	Sardines, in oil, drained	351
3 oz	Perch, cooked	117
1 cup	Tofu	260
1-1/2 cups	Chef salad	235
1	Taco	221
1	Plain hamburger, large, with bun	74
1 cup	Almonds	332
1 cup	Collard greens, chopped, cooked	357
1 cup	Kale, chopped, cooked	179
1 cup	Broccoli, cooked	94
1 cup	Kidney beans, canned	69
10 fl oz	Milk shake, vanilla	344
1 cup	Ice cream, vanilla	170
5 oz	Tapioca pudding	119

Source: Agricultural Handbook, U.S. Department of Agriculture.