What are bones made of?

The best ways to prevent osteoporosis are to get enough calcium, vitamin D and exercise.
The best ways to prevent osteoporosis are to get enough calcium, vitamin D and exercise.

Bones are uniquely constructed to carry the weight of our bodies and to perform other functions, such as growing blood cells.  They are living structures that are continually being built and broken down. For about the first 20 or 30 years of your life, your body creates more bone than it loses. After that, the ratio is reversed, and you lose more bone than you grow. 

Minerals, especially calcium, are important to build bones and keep them strong. The more minerals your bones contain, the denser they are and the lower your risk of fractures. They are more likely to break if you have osteoporosis

What is osteoporosis?

Osteoporosis means "porous bones." Bones have a hard, solid exterior, but the interior is a sponge-like structure with many holes. If you have osteoporosis, the holes are larger. The outer shell of your bones may also be thinner. The combination of these two changes means that your bones are more likely to break. 

Most people who have osteoporosis have no symptoms. In the United States, about half of women over 50 will break a bone because of osteoporosis. Men can have osteoporosis, too, but they start out with heavier bones and lose bone density more slowly than women.  

Besides being female, some risk factors for osteoporosis are out of our control, including:

  • Being over 60, with risk increasing with advancing age
  • Having a family history of osteoporosis or bone fractures
  • Having suffered a broken bone in the past
  • Having gone through menopause early or had a hysterectomy before menopause
  • Having taken certain medications, including thyroid hormones, steroids, some antidepressants, and others
  • Having another condition that puts you at risk, including rheumatoid arthritis, cancer, and others

Risk factors that you can control include:

  • Smoking
  • Having more than two alcoholic beverages a day
  • Being underweight, with a body mass index of less than 19
  • Poor nutrition
  • Low intake of Vitamin D and calcium
  • Inactive lifestyle

How to prevent osteoporosis

Get enough calcium

Calcium intake is important in osteoporosis prevention. Many foods contain calcium, and it is possible to get enough without taking a supplement. Most people know that dairy products contain calcium. Other good sources include leafy greens, winter squash, almonds, tofu, edamame, and canned salmon and sardines. Plant milk and orange juice are often fortified with calcium.

The Recommended Daily Allowance (RDA) for calcium is 1000-1200 mg daily. Nutritional labels are based on 1000 mg a day, so keeping up with your consumption is fairly easy. A food containing 100 mg would provide 10% of your need. Some of the calcium found in plants is not bioavailable, meaning the body can't absorb it. For that reason, you might want to take a calcium supplement. 

Doctors do not recommend taking big doses of calcium, since too much calcium can cause other health problems. If you routinely get calcium from your diet, look for small supplements to take when your dietary sources fall short.

Get more vitamin D

Without sufficient vitamin D, your body may not absorb the calcium you take in. Our bodies manufacture vitamin D when exposed to sunlight, but we don't always get enough exposure to meet our needs. Fortified milk and dairy products contain vitamin D, as do fish, eggs, and shellfish, but dietary sources rarely provide enough D. 

The best solution may be to take a supplement. You will find vitamin D available as D2 or D3. Both are effective. The RDA is 400 IUs for ages 51-70 and 600 IUs for those over 70, but it may be easier to find supplements of 1000 to 2000 IUs. Don't go over that amount, since you can get too much vitamin D.

Get some exercise 

Another important step in osteoporosis prevention is exercise. Putting stress on the bones through exercise increases bone growth. The most effective exercises are high-impact and weight-bearing, such as running and jumping, but these activities aren't appropriate for everyone. 

Other weight-bearing activities, such as walking or stair climbing, can be substituted. Strength training, also known as resistance training, builds bone in a different way, through the action of muscles pulling on the bones. 

Exercises only affect the part of the body that is being used. For example, walking strengthens the bones of the lower body but not the ribs or wrists. In addition, if you stop exercising, you will lose the benefits you gained. 


Check with your doctor

How to know if you have osteoporosis

A bone density scan can tell you whether you have osteoporosis. The test is quick and non-invasive and uses only a small dose of radiation. The bones in the spine and hip are checked most often, as that is where the most serious fractures tend to occur. 

Women over 65 and most men over 70 should have a test, and the test should be repeated periodically, depending on your results. If you are younger but at high risk of osteoporosis, you may need a scan. 

When you get your bone density results, your doctor will help you understand them. You may be told that you have normal bone density, low bone density (osteopenia), or osteoporosis. If your bone density is below normal, your doctor may suggest a medication for osteoporosis.  

Treating osteoporosis with medications

Medications for osteoporosis can reduce the risk of hip fracture by up to 40% and also lower the likelihood of other fractures. Medications come in two varieties: ones that prevent bone loss and ones that promote bone growth. Like almost all medicines, these drugs have side effects. They can also be expensive. Your doctor can work with you to find a cost-effective medication that fits your needs.

Even if you take medication for osteoporosis, you should keep up your levels of vitamin D and calcium and participate in exercise that is appropriate for you.  



What is another medical term for osteoporosis? See Answer

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Medically Reviewed on 2/3/2021

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National Institute on Aging: "Osteoporosis."

National Osteoporosis Foundation: "Bone Density Scan/Testing."

Postgraduate Medical Journal: "Osteoporosis and Exercise."

University of Wisconsin Health: "How Exercise Influences Bone Health."