Calcium: What You Should Know

Calcium is best known as the structural component of bones and teeth. Although 99% of the calcium in the body is found in the bones, this calcium acts as a reservoir for the small but crucial amounts of calcium used for other purposes. Calcium plays an essential role in muscle contraction (including heartbeats), nerve transmissions, blood clotting, and maintaining the acid-alkaline balance of blood. In fact, these functions are so important that if dietary calcium is insufficient, blood levels are maintained at the expense of bones. That is, if necessary, the mineral is taken from bones to restore blood calcium to ideal levels.

Osteoporosis is the disease most commonly associated with calcium. Calcium may also be influential in regulating blood pressure, reducing PMS, and lowering colon cancer risk.

Recommended Daily Calcium Intakes
Up to 6 months, 400 mg.
6 months to 4 years, 600 mg.
4 to 8 years, 800 mg.
9 to 18 years, 1,300 mg.
19 to 50 years, 1,000 mg.
51 years and over, 1,200 mg.
pregnant and nursing women, 1000 (1,300 if under 18)

Some food sources of calcium are more efficiently used by the body. Conversely, there are a variety of conditions that favor or lower calcium utilization. Thus, depending on overall diet and lifestyle factors, individual calcium needs can vary from these recommendations. Note that high calcium intake can interfere with the absorption of other nutrients. People who take calcium in supplement form are advised to also supplement their diets with at least 15 mg. of zinc.

Factors that can interfere with calcium absorption and retention
Lactose intolerance
Excessive animal protein
Excessive alcohol
Excessive caffeine
Cigarette smoking
Sedentary lifestyle
Drug interactions
Birth control pills
Exercise-induced amenorrhea
Aluminum-based antacids
Inadequate stomach acid
Lack of vitamin D
Inadequate vitamin K
Excess phosphorus
Excessive fiber in diet
Excessive fats in diet
Oxalic acid from certain vegetables, fruit and cocoa beans
Inadequate amounts of the minerals magnesium, manganese, copper, zinc, boron, silicon

Food Sources of Calcium

Note: To determine how much calcium there is from a food label, multiply the percent calcium by 10 for the number of milligrams per specified serving; i.e. 25% DV (daily value) calcium = 250 mg.

Food

Amount

Calcium Value (mg)

Cow’s milk

1 cup

290

Fortified soy milk

1 cup

200-300

Yogurt, nonfat

1 cup

350-450

Yogurt, whole milk

1 cup

300

YoChee, nonfat

½ cup

235

Cottage cheese

½ cup

60

Ricotta cheese

½ cup

330

Cheese, natural, i.e. cheddar, Swiss, mozzarella

1 ounce

200

Parmesan cheese, grated

1 tablespoon

80

Feta cheese

1 ounce

140

Ice Cream

½ cup

160

Tofu (with calcium coagulant)

4 ounces, firm

230

Soy nuts (roasted soybeans)

½ cup

230

Soybeans (dried, cooked)

1 cup

175

Soybeans (fresh green, edamame)

1 cup

260

Tempeh

4 ounces

100

Almonds

½ cup

190

Almond butter

2 tablespoons

85

Brazil nuts

½ cup

140

Pistachio nuts, shelled

½ cup

85

Sunflower seeds

½ cup

45

Tahini

¼ cup

256

White beans (navy, northern)

1 cup

120

Black beans

1 cup

100

Chickpeas, pinto beans

1 cup

80

Salmon, sockeye, with bone

½ cup

180

Sardines canned with bone

2 ounces drained weight

215

Mackerel canned with bone

½ cup

230

Broccoli

1 cup cooked

85

Spinach

1 cup raw

55

Spinach

1 cup cooked

245

Kale

1 cup cooked

95

Bok choy

1 cup cooked

160

Beet greens

1 cup cooked

165

Mustard greens

1 cup cooked

150

Swiss chard

1 cup cooked

100

Collard greens

1 cup cooked

226

Seaweed: nori, kelp, arame, wakame, hijiki

¼ cup

35

Orange squash, acorn/butternut

½ cup

45

Corn Tortillas

3

120

Dried figs

3

80

Dark molasses

1 tablespoon

100