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Nutrition

What girls need to know about bone health

What is osteoporosis?
Why should I be worried about bone health now?
What is "weight bearing" physical activity?
How do calcium and physical activity make bones stronger?
How much calcium do I need? Does this mean I have to drink a lot of milk?
Should I take a calcium supplement (pill or powder) to make sure I get enough?
Can you get too much calcium?
Can I get enough calcium if milk upsets my stomach?
Are dairy products fattening?
I've heard that soda is bad for my bones. Why?
What else can I do to improve my bone health?
How can girls take part in weight bearing physical activity while staying indoors?
What kinds of weight bearing exercises can girls with physical disabilities do to keep their bones strong?
For more information…

What is osteoporosis? top

Osteoporosis (say: ah-stee-oh-per-oh-sis) is a disease that thins and weakens bones to the point where they break easily. Hip, spine (backbone) and wrist bones are often involved. It is called a "silent disease" because bone loss happens without much notice. Having a bone break easily or getting a little shorter is often the first sign of this disease. While osteoporosis can strike at any age, over half of all women over age 65 have it.

There are certain things that are linked to your chances of getting osteoporosis. These things are called risk factors. Some risk factors cannot be changed, while others can be changed.

Risk factors that CANNOT be changed include:

• Sex. Women are more likely to develop the disease than men are. Women have lighter, thinner bones to begin with and their bones become thinner quickly after menopause (when periods stop for good).
• Age. The longer you live, the greater your chances are of getting the disease. The amount of bone loss varies among women, and not all women get osteoporosis.
• Family history. This disease runs in families, which means your risk of getting it is greater if someone in your family has the disease.
• Body size. Women who are small-boned and thin have a higher risk than women who are larger-boned and weigh more. But, being heavy does not mean that you will not get this disease.
• Ethnicity. White and Asian women are at greater risk for this disease. Black and Hispanic women do get osteoporosis, though.

Risk factors that CAN be changed include:

• Diet. Getting enough calcium and vitamin D in your diet will help you to build and keep strong, healthy bones.
• Physical activity. Exercise helps keep bones strong and healthy over your lifetime.
• Smoking. Smoking lowers the level of the hormone estrogen in your body, which can cause you to go through menopause earlier, boosting your risk for osteoporosis.

Why should I be worried about bone health now? top

It is never too early to start worrying about bone health. Your peak bone-making years are in your childhood and teen years. If you do not make enough bone as a kid, your risk for osteoporosis goes up. And, while not common, a young woman can get osteoporosis. Having good eating and exercise habits now will help you to have strong, healthy bones throughout your life. A poor diet and not enough physical activity as a teen can cause you to have weaker bones as an adult. This not only makes it easier to get osteoporosis, it can hurt the body's ability to heal right after an injury. Getting enough calcium and doing enough weight bearing physical activity can help protect your bones.

What is "weight bearing" physical activity? top

Weight bearing physical activity is any activity in which your body works against gravity, so your feet and legs are supporting or carrying your weight. Examples of weight bearing physical activities that you can do include walking, running, tennis, dancing, tae kwon do, hiking, hopscotch, and basketball.

Activities that are not weight bearing include riding a bike, swimming, and skateboarding. But, these activities are good for overall health and can be mixed in with weight bearing activities.

How do calcium and physical activity make bones stronger? top

To make bones strong and to keep them strong, the body needs both calcium and weight bearing physical activity. One or the other is not enough to make bones strong—it takes two!

• Calcium helps bones to grow right. When the body makes new bone tissue, it first lays down a framework of a protein called collagen. Then, calcium from the blood spreads throughout the collagen framework. The hard crystals of calcium attach to the bone structure. Calcium and collagen work together to make bones both strong and flexible.
  
  Calcium is also needed for many other activities within the body such as neural communication (the way your nerves and brain send signals to each other) and heart and lung functions. If the body doesn't get enough calcium from foods and drinks, it takes it from bones, which can make them weaker.
• Physical activity helps bones become stronger and thicker, just as a muscle gets stronger and bigger the more you use it. Bones are living tissue. Weight bearing physical activity causes new bone tissue to form, making bones even stronger. It also makes muscles stronger, and muscles push and tug against bones to make them even stronger. Physical activity also makes you better coordinated, which can make you less likely to fall and break a bone.

How much calcium do I need? Does this mean I have to drink a lot of milk? top

Girls ages 9 - 18 should get 1300 milligrams of calcium per day. But, so many girls don’t get nearly enough calcium.

There are lots of ways to get calcium, including milk. The chart below lists the amount of calcium that is found in different foods and drinks. As you can see, there are lots of good tasting foods and drinks you can choose to make sure you get enough calcium. Just add it up to 1300 milligrams each day!

FOOD	PORTION SIZE	CALCIUM (Milligrams)*
Plain, fat-free yogurt	1 cup	450
Grilled cheese sandwich**	1 sandwich	371
American cheese	2 ounces	350
Ricotta cheese, part skim	½ cup	340
Fruit yogurt	1 cup	315
Milk (fat-free, low-fat, or whole)	1 cup	300
Orange juice with added calcium	1 cup	300
Soy beverage with added calcium	1 cup	250-300
Cheese pizza	1 slice	220
Cheddar cheese	1 ounce	204
Tofu (made with calcium)	½ cup (about five 1-inch cubes)	204
Macaroni and cheese	½ cup	180
Cottage Cheese	1 cup	138 mg
Frozen yogurt (fat-free or low-fat)	½ cup	105
Broccoli, cooked or fresh	1 cup	90
Ice cream	½ cup	84
Bok choy, cooked or fresh	½ cup	80
Almonds, dry roasted	1 ounce(About 20-25 almonds)	71
White bread	2 slices	70

* Amount of calcium depends on the ingredients of many foods.
** Using 2 slices of white bread, 1-½ ounces of cheese, and nonstick cooking spray.

Getting 1300 milligrams of calcium just from food seems kind of hard. Should I take a calcium supplement (pill or powder) to make sure I get enough? top

You can get plenty of calcium from foods and drinks. It's found in a variety of good tasting foods like milk, yogurt, broccoli, and low-fat cheese. Many foods also have extra calcium added to them, like orange juice, milk, breakfast cereals, cereal and other types of bars, and soy drinks. Be sure to check food package labels to see if they have added calcium. Girls who have allergies or other dietary limitations should ask their doctor about calcium supplements. But, most girls can get enough calcium by eating the right types of foods.

Can you get too much calcium? top

While it is possible to get too much calcium, it is not likely for most girls. Even with all the products that have added calcium, many girls take in far less calcium each day than the 1300 milligrams they need.

Can I get enough calcium if milk upsets my stomach? top

Yes. Lactose intolerance means some girls get a stomachache or have gas after they have milk or other dairy products. The good news is that there are milk and other dairy products that are specially made for people with lactose intolerance. Look for milks, cheeses, cottage cheese and other products that are made with the enzyme lactase, which helps people digest dairy. You can also buy Lactaid pills to chew or swallow with the first bite of dairy, which also have lactase. There are also other foods that have calcium like broccoli, almonds, and foods that have added calcium like orange juice and cereals. Remember to look for "calcium" on food labels.

Are dairy products fattening? top

There are many low-fat or non-fat milk products available. Also, there is the same amount of calcium in non-fat and low-fat milk. Dairy products are a very important part of teen's diet. They provide calcium, vitamin D and other nutrients that help prevent osteoporosis.

There are good non-dairy sources of calcium. But, dairy products offer the most calcium per serving. For example, one cup of fat-free or low-fat milk has about 300 milligrams of calcium. One cup of broccoli (cooked or fresh) has about 90 milligrams of calcium.

I've heard that soda is bad for my bones. Why? top

Many sodas, including colas, have caffeine – the same ingredient in coffee and tea. Caffeine itself does not seem to harm bone health. But, young girls often choose soft drinks with caffeine over milk and other drinks high in calcium. If you drink sodas with caffeine and sugar, you will have less room for bone-healthy drinks like milk and drinks that have extra calcium added to them (milk, soy milk, orange juice).

What else can I do to improve my bone health? top

Steer clear of alcohol and smoking, and make sure your diet is healthy overall. Smoking, drinking alcohol, and having eating disorders such as anorexia nervosa or bulimia can cause weaker bones. If you have any of these habits and would like to stop, ask an adult that you trust for help. It is best, though, to never start these dangerous behaviors.

My neighborhood is not very safe. How can girls take part in weight bearing physical activity while staying indoors? top

There are plenty of indoor weight bearing exercises that you can do to get strong, healthy bones. Dancing, lifting hand-held weights (or soup cans), jogging in-place, and push-ups can be done both indoors and outdoors.

What kinds of weight bearing exercises can girls with physical disabilities do to keep their bones strong? top

Examples of weight bearing exercises for girls with physical disabilities:

• Wheelchair aerobics combines upper body movements and stretches to improve flexibility. They are done in a seated position, often to music.
• Arm cycling (ergometry) is like bicycling, only it is done with the arms instead of the legs. A girl can use a stationary (non-moving) bike or arm-driven cycles made for outdoor use. Always wear a helmet when cycling outdoors.
• Wheeling involves moving a wheelchair forward, using the arms or legs, over an extended distance. This can be done inside or outside, using a regular wheelchair or a specialized sport wheelchair.
• Resistance training uses wide elastic bands. One end of a band is attached to a non-moving object, such as a doorknob or the leg of a bed or a heavy table, while the other end is held and stretched to exercise one part of the body at a time. Hand weights can also be used for this type of training.
• Some sports can be adapted for girls with physical disabilities, like wheelchair tennis and wheelchair basketball.

To learn more about bone health, check out... top

 Powerful Bones. Powerful Girls.

Why Milk Matters Now, For Children and Teens (PDF - 5MB)

 

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Content last updated July 3, 2007

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