Calcium And Osteoporosis


Osteoporosis is a decrease in bone mineralization or bone density, which causes an increased risk for fractures. Osteoporosis causes 1.5 million hip fractures each year in the U.S., resulting in $13.8 billion in health care costs.

Calcium plays a role in decreasing the risk for osteoporosis by increasing bone density. It is important to consume adequate calcium while you are young (see table below), as your bones are able to take up calcium and other minerals to increase bone density until about age 30. After age 30, the reverse happens and minerals are lost at a higher rate, thus decreasing bone density and increasing the risk for osteoporosis.

This doesn’t mean that after age 30 you are doomed to develop osteoporosis. There are things you can do to prevent the development of osteoporosis and maintain bone density if you have osteoporosis.

Calcium: Calcium is used for many bodily functions, such as muscle contraction and relaxation, acid base balance, nerve function as well as bone and teeth formation. If you don’t consume enough calcium, your body will pull calcium out of the bone to facilitate these other functions, decreasing bone density. The table below shows the amount of calcium one needs during various life stages.

Life Stage Group
Calcium Goal (mg/day)
1-3 years 500
4-8 years 800
9-18 years 1,300
19-50 years 1,000
> 50 years 1,200
Pregnant/Lactating up to 18 years 1,300
19-50 years 1,000
Diagnosis of Osteoporosis 1,500

Like most nutrients, calcium is better absorbed from food sources, however, supplemental calcium can be helpful if it is difficult to consume adequate amounts from food. A variety of calcium supplements are available. The typical multivitamin with mineral contains 200-250 mg of calcium. Most women’s formula multivitamin with mineral have about 450 mg of calcium. Supplemental calcium can be obtained alone from chewable sources, such as Tums (350 mg) or Viactiv (500 mg), and from supplements that you swallow whole (500-600 mg). If you are taking more than one calcium supplement it is better to take them at separate times with food to enhance absorption.

Food Source & Serving Calcium (mg)
Yogurt 1 cup 350-450
Milk (skim, low fat or whole) 1 cup  300-330
Cheese 1 ounce 200-250
Broccoli, cooked 1 cup 135
Bok Choy, cooked 1 cup 250
Calcium Fortified Orange Juice 1 cup 300
Tofu 4 ounces 50-250
Almonds, 2 ounces, 24 nuts 132
Black beans, 1 cup 105
Kidney beans, 1 cup 115

Vitamin D: Vitamin D is needed so your body can absorb calcium. Most dairy products are fortified with vitamin D. You do not necessarily need to consume foods with vitamin D as your body has the capacity to make vitamin D if your skin exposed to ultraviolet light (i.e. sunlight). Exposing your face, neck and arms to sunlight for 5-10 minutes a day should provide you with enough ultraviolet light to make vitamin D. People at greatest risk for vitamin D deficiency are those who don’t get regular sun exposure, such as those in northern or southern latitudes and those who are home bound or institutionalized.

Exercise: Weight bearing exercise, such as walking, running, lifting weight and dancing help to maintain and possibly increase bone density. The benefits to weight bearing exercise seem to occur in women only when estrogen levels are adequate. Therefore, young amenorrheic or menopausal women (women who are no longer getting a period) who are not taking hormone replacement therapy, weight bearing exercise does not have a beneficial effect.