What Is Healthy Bone Mass?

Strong bones are crucial for good health and aging well. Maintaining a healthy bone mass percentage helps prevent osteoporosis and broken bones. While childhood is the most important time for building bone health, it's never too late to take care of your bones.

Like all living tissues in your body, your bones are constantly changing. Old bone is broken down and new bone is constructed in a process called bone remodeling. Bone mass, also sometimes called bone density, is a measure of the amount of bone tissue in the skeleton at any given time. This changes throughout your lifespan and depends on many factors, including your age, gender, diet and health.

Childhood and adolescence is the period of greatest bone density. During this time, the body builds more bone than it breaks down; the size of the skeleton grows, and the bones become denser. Bones can keep growing throughout a person's 20s. At this time, the bones have reached their potential for strength and density.

From 30 onward, bone still rebuilds itself; however, the pace of bone breakdown may exceed the formation of new bone. The bigger the difference between breakdown and buildup, the lower your bone mass or density becomes.

Read more: 8 Foods for Healthy Bones (and 3 Foods That Negatively Impact Bone Health)

It's not possible to see or feel if your bone mass is decreasing. Doctors can use a bone mineral density test to measure the amount of the minerals calcium and phosphorous that your bone contains. This gives them an accurate picture of your bone mass and bone health.

A central dual-energy x-ray absorptiometry, or central DXA, test is the most commonly performed type of bone density test, according to the National Institutes of Health. The DXA test measures bone density at the hip and lower spine. Just like having an X-ray, the procedure is painless.

The results of your bone density test are compared to an average bone mineral density of a healthy young adult, after which you will be given a score, called a T score. A T score of zero means you have ideal bone mass, according to the NIH. A score below -2.5 indicates very low bone mass and a condition called osteoporosis.

A bone mineral density test can tell you only your current bone mass; it can't show whether you are currently losing bone or building bone. In order to measure bone loss, you need to take two tests spaced about two months apart, according to the New York State Department of Health.

If your test reveals that you have low bone mass, that doesn't mean you will automatically develop osteoporosis, a condition in which the bones become fragile and break easily. However, low bone mass, called osteopenia, increases your risk for osteoporosis. Causes of low bone mass include:

• Hereditary factors
• Low body weight
• A medical condition or medication affecting bone mass

If you have low bone mass, healthy habits can help you slow bone loss and prevent osteoporosis. Eating foods rich in the mineral calcium and vitamin D and doing weight bearing exercise, such as walking, jogging and lifting weights, can help strengthen your bones. In some cases, your doctor may recommend medication to prevent further bone loss and osteoporosis.

Osteoporosis affects approximately 10 million Americans, according to the National Osteoporosis Foundation; about 80 percent of these are women. In 50 percent of women over age 50, osteoporosis will cause a broken bone. Women are more prone to osteoporosis because their bones are smaller and thinner. Additionally, levels of the female hormone estrogen, which helps protect bones, declines sharply after menopause.

If your doctor diagnoses you with osteoporosis, the same healthy habits that help with low bone mass can help your condition. However, healthy habits alone aren't enough; your doctor will also likely recommend medication that can slow and even reverse bone loss.

Read more: Yoga Poses to Avoid With Osteoporosis

The most important time for building strong bones is in childhood and adolescence. Eating a balanced diet including plenty of calcium and vitamin D and getting plenty of physical activity early in life contributes to the formation of strong, healthy bones. The stronger bones start out, the lower the risk of low bone mass and osteoporosis later in life.

But even in adulthood, you can take steps to maintain healthy bone mass as you get older:

• Eat a nutrient-rich diet, including plenty of vegetables and fruits.
• Eat foods rich in calcium, including dairy, sardines, kale, tofu and fortified orange juice and cereal. Adult males between the ages of 19 and 70 and women ages 19 to 51 need 1,000 milligrams a day; women ages 51 to 70 need 1,200 milligrams daily.
• Take a calcium supplement if you can't get enough from your diet.
• Get plenty of vitamin D from foods such as swordfish, salmon, egg yolks, fortified dairy products, orange juice and cereal. All adults ages 19 to 70 need 600 IU of vitamin D each day.
• Take a vitamin D supplement if necessary.
• Engage in physical activity every day.
• Don't smoke, as smoking can weaken your bones.
• Limit your alcohol intake.