Health Matters

Calcium: What is it?

Taking calcium regularly, every day, is key to preventing
and treating calcium deficiency and to helping reduce
the risk of osteoporosis.

Calcium, the most abundant mineral in the human body,
has several important functions. More than 99% of total
body calcium is stored in the bones and teeth where it
functions to support their structure [1]. The remaining
1% is found throughout the body in blood, muscle, and
the fluid between cells. Calcium is needed for muscle
contraction, blood vessel contraction and expansion, the
secretion of hormones and enzymes, and sending
messages through the nervous system [2]. A constant
level of calcium is maintained in body fluid and tissues
so that these vital body processes function efficiently.

Bone undergoes continuous remodeling, with constant
resorption (breakdown of bone) and deposition of
calcium into newly deposited bone (bone formation) [2].
The balance between bone resorption and deposition
changes as people age. During childhood there is a
higher amount of bone formation and less breakdown. In
early and middle adulthood, these processes are
relatively equal. In aging adults, particularly among
postmenopausal women, bone breakdown exceeds its
formation, resulting in bone loss, which increases the
risk for osteoporosis (a disorder characterized by
porous, weak bones) [2].

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.

You can get the amount of calcium required daily through a variety of foods. Milk and dairy products offer the
biggest source of calcium. Green leafy vegetables are another source of calcium. Therefore, eating a balanced
diet with a variety of foods is very important.

What foods provide calcium?

In the United States (U.S.), milk, yogurt and cheese are the
major contributors of calcium in the typical diet [4]. The inadequate
intake of dairy foods may explain why some Americans are deficient in calcium since dairy foods are the major
source of calcium in the diet [4]. The U.S. Department of Agriculture's Food Guide Pyramid recommends that
individuals two years and older eat 2-3 servings of dairy products per day. A serving is equal to:
1 cup (8 fl oz) of milk
8 oz of yogurt
1.5 oz of natural cheese (such as Cheddar)
2.0 oz of processed cheese (such as American)

A variety of non-fat and reduced fat dairy products that contain the same amount of calcium as regular dairy
products are available in the U.S. today for individuals concerned about saturated fat content from regular dairy
products.

Although dairy products are the main source of calcium in the U.S. diet, other foods also contribute to overall
calcium intake. Individuals with lactose intolerance (those who experience symptoms such as bloating and
diarrhea because they cannot completely digest the milk sugar lactose) and those who are vegan (people who
consume no animal products) tend to avoid or completely eliminate dairy products from their diets [2]. Thus, it is
important for these individuals to meet their calcium needs with alternative calcium sources if they choose to avoid
or eliminate dairy products from their diet. Foods such as Chinese cabbage, kale and broccoli are other
alternative calcium sources [2]. Although most grains are not high in calcium (unless fortified), they do contribute
calcium to the diet because they are consumed frequently [2]. Additionally, there are several calcium-fortified food
sources presently available, including fruit juices, fruit drinks, tofu and cereals. Figure 1 compares portion sizes of
various foods that provide the amount of calcium in one cup of milk. This figure takes into account that calcium
absorption varies among foods. Certain plant-based foods such as some vegetables contain substances which
can reduce calcium absorption. Thus, you may have to eat several servings of certain foods such as spinach to
obtain the same amount of calcium in one cup of milk, which is not only calcium-rich but also contains calcium in
an easily absorbable form.

Food/ Calcium (mg)

Yogurt, plain, low fat, 8 oz. 415
Yogurt, fruit, low fat, 8 oz. 245-384
Sardines, canned in oil, with bones, 3 oz. 324
Cheddar cheese, 1 ½ oz shredded 306
Milk, non-fat, 8 fl oz. 302
Milk, reduced fat (2% milk fat), no solids, 8 fl oz. 297
Milk, whole (3.25% milk fat), 8 fl oz 291
Milk, buttermilk, 8 fl oz. 285
Milk, lactose reduced, 8 fl oz.** 285-302
Mozzarella, part skim 1 ½ oz. 275 28%
Tofu, firm, made w/calcium sulfate, ½ cup*** 204
Orange juice, calcium fortified, 6 fl oz. 200-260
Salmon, pink, canned, solids with bone, 3 oz. 181
Pudding, chocolate, instant, made w/ 2% milk, ½ cup 153
Cottage cheese, 1% milk fat, 1 cup unpacked 138
Tofu, soft, made w/calcium sulfate, ½ cup*** 138
Spinach, cooked, ½ cup 120
Instant breakfast drink, powder prepared with water, 8 fl oz. 105-250
Frozen yogurt, vanilla, soft serve, ½ cup 103
Ready to eat cereal, calcium fortified, 1 cup 100-1000
Turnip greens, boiled, ½ cup 99
Kale, cooked, 1 cup 94
Kale, raw, 1 cup 90
Ice cream, vanilla, ½ cup 85
Soy beverage, calcium fortified, 8 fl oz. 80-500
Chinese cabbage, raw, 1 cup 74
Tortilla, corn, ready to bake/fry, 1 medium 42
Tortilla, flour, ready to bake/fry, one 6" diameter 37
Sour cream, reduced fat, cultured, 2 Tbsp 32
Bread, white, 1 oz 31
Broccoli, raw, ½ cup 21
Bread, whole wheat, 1 slice 20 2
Cheese, cream, regular, 1 Tbsp 12

Recomended Calcium intake Mg/day

0 to 6 months - 210
7 to 12 months - 270
1 to 3 years - 500
4 to 8 years - 800
9 to 13 years - 1300
14 to 18 years - 1300
19 to 50 years - 1000
51+ years - 1200

The following are strategies and tips to help you meet your calcium needs each day:

Use low fat or fat free milk instead of water in recipes such as pancakes, mashed potatoes, pudding and
instant, hot breakfast cereals.
Blend a fruit smoothie made with low fat or fat free yogurt for a great breakfast.
Sprinkle grated low fat or fat free cheese on salad, soup or pasta.
Choose low fat or fat free milk instead of carbonated soft drinks.
Serve raw fruits and vegetables with a low fat or fat free yogurt based dip.
Create a vegetable stir-fry and toss in diced calcium-set tofu.
Enjoy a parfait with fruit and low fat or fat free yogurt.
Complement your diet with calcium-fortified foods such as certain cereals, orange juice and soy beverages.

Signs of calcium deficiency

Because circulating blood calcium levels are tightly regulated in the bloodstream, hypocalcemia (low blood
calcium) does not usually occur due to low calcium intake, but rather results from a medical problem or treatment
such as renal failure, surgical removal of the stomach (which significantly decreases calcium absorption), and use
of certain types of diuretics (which result in increased loss of calcium and fluid through urine). Simple dietary
calcium deficiency produces no signs at all. Hypocalcemia can cause numbness and tingling in fingers, muscle
cramps, convulsions, lethargy, poor appetite, and mental confusion. It can also result in abnormal heart rhythms
and even death. Individuals with medical problems that result in hypocalcemia should be under a medical doctor's
care and receive specific treatment aimed at normalizing calcium levels in the blood. [Please note that the
symptoms described here may be due to a medical condition other than hypocalcemia.] It is important to consult a
health professional if you experience any of these symptoms.