Classroom Activities

Building Better Bones

Activity Outcome:

Students will be able to:

• Identify the functions of the human skeleton.
• Discuss the relationship between diet and strong bones.
• Identify calcium-rich foods.
• Make a plan to increase milk, cheese and yogurt consumption.

Activity Synopsis:

Students discuss the skeletal system and the relationship between strong bones and a healthful diet rich in calcium.

Materials and Advance Prep:

• • Skeleton (poster, drawing or model)
  • It’s Just another Day: Your Food Story! handout
  • It’s Just another Day: Your Food Findings! worksheet
  • Guide to Good Eating
  • Where’s the Calcium? handout (optional)
  • Food labels collected by students of different foods they usually eat.

The labels should include at least one item from each food group and one item from the “Other” category. For example: cereal or bread (Grain), green beans (Vegetable), 100 % orange juice (Fruit), yogurt or milk chug (Milk), peanut butter or egg carton (Meat & Beans), and candy, salad dressing or soft drink (“Others” category).

• Did You Feed Your Bones Today? worksheet
• Take Interest in Strong Bones worksheet
• Improve Diet Quality with 3-A-Day of Dairy handout (optional)

What To Do

Session One:

• Distribute It’s Just another Day: Your Food Findings!  worksheets, one to each student.
• Read It’s Just another Day: Your Food Story! and instruct students to select food choices as you read. Collect the worksheets.

Session Two:

Students discuss the skeletal system and the relationship between strong bones and a healthful diet rich in calcium.

• Display the skeleton and pose the following questions:

• What makes up the skeleton? Bones.
• What percentage of body weight is bone? 16%.
• How many bones make up an adult skeleton? 206.
• What is the largest bone in your body? Femur (thighbone).
• What is the smallest bone in your body? Three tiny bones inside the ear are the smallest – the hammer, the anvil, and the stirrup (smallest). These bones look like their names and together are about the size of your thumbnail.
• What does the skeleton do? The skeleton is the frame that supports all the other body systems, giving the body its shape. It protects vital organs such as the heart, lungs, and brain.
• What do we call the bones that protect the heart and lungs? Ribs. Most people have 12 pairs of ribs: 10 pairs meet in the front to protect your heart and lungs, and 2 pairs are too short and do not reach all the way around.
• What protects the brain? The skull.
• Can bones bend? No. We bend our arms, legs, and other parts of our body at places where two bones join together.
• What do we call these places, where two bones join together? Joints.

• Explain the following:

• Bones are living tissues and are constantly changing. Old bone is broken down and replaced with new bone. This is called remodeling.
• Because bones are living tissues, they need to be fed!
• Many vitamins and minerals help build bones and keep them strong. The mineral calcium is the most important nutritional factor that determines how strong our bones become.
• Calcium is very important during the “growing” years. During the teen years, you gain about 15 percent of your adult height and almost half of your bone structure. This means your bones are getting not only longer, but also thicker and stronger.
• Since the body cannot make its own calcium, it must be supplied by the foods we eat.
• When you eat foods rich in calcium, your body uses the calcium it needs for different jobs – to build and maintain strong bones and to help the heart beat, the nerves transmit messages, the blood clot, and muscles contract. Very important jobs! 
• Your bones act as a “storehouse” or “bank” for calcium. When you eat foods rich in calcium, your body stores the extra calcium in your bones. It is like depositing money in a savings account so you will have it later, when you need it.
• If you do not give your bones enough calcium, your body will take it from your “bone-bank.” Withdrawing too much calcium from your “bone-bank” can weaken your bones.
• The goal is to “deposit” enough calcium in your “bone-bank” to keep you active and strong today and tomorrow! Whether you’re 5, 15 or 55, the amount of calcium in your diet affects the strength of your bones. Bones still need calcium to grow strong after they finish growing in length.
• There are other nutrients needed to build strong bones - vitamin D, vitamin A, phosphorus, magnesium, and protein. Vitamin D helps your body absorb calcium. Vitamin A is important for bone growth as well as healthy vision, especially in the dark. Phosphorus is a mineral that is a major component of bones and teeth. Magnesium is another mineral that helps build dense bones. Finally, protein helps build bones and muscle and repair damaged muscles.
• Physical activity is important for building strong bones and muscles. Weight bearing activities stimulate your bones to grow and to become strong. Activities that involve the repeated action of your feet hitting the ground are the best bone-building activities. What are examples of weight-bearing activities? Walking, running, soccer, baseball, basketball, tennis, aerobic dancing, jumping, climbing stairs, weight-lifting, and aerobics are all muscle-building activities. Physical activity also stimulates muscles to grow. What types of activities build muscles? Weight lifting and resistance training, doing push-ups or sit-ups, or even doing work around the house or garden that makes you lift or dig.

Session Three:

• Review key points from session two, emphasizing the importance of a daily dose of calcium for building and maintaining strong and healthy bones.
• Explain that children and teens, 9- to 18-years-old, need at least 1300 milligrams of calcium each day. This translates to four servings from the Milk Group daily to meet that need.
• Give each student a copy of The Guide to Good Eating handout. Explain that the Milk Group has the most calcium-rich foods, such as milk, cheese and yogurt.
• Point out that there are foods in other food groups that supply calcium as well. Using The Guide to Good Eating handout, identify calcium sources from the Meat Group (tofu processed with calcium, sardines and salmon with bones, almonds, and beans), Vegetable Group (kale, broccoli, beet greens, and okra), and Grain Group (English muffin, pancakes, or corn tortilla). Optional: Check Where is the Calcium? handout for more details about calcium-rich foods.
• Ask students to pull out their food labels.
• Review the Nutrition Facts panel. Use the Nutrition Facts panel to show the amount of calcium found in a serving of food. Explain that:
• Foods providing 10-19% Daily Value are good sources of calcium; foods providing 20% or more are excellent sources.
• The % DV is key to getting enough calcium, and for their age, students need to eat 130% of the DV for calcium.
• Explain that looking at the % Daily Value can help us select calcium-rich foods. Have students sort their food labels into the following categories based on calcium content: None (0-2%), little (3-9%), good (10-19%), and excellent (20% or more).
• Draw a 6 column table on the board and label each section with the appropriate food group name and “others” category. Have students post the labels that are good or excellent sources in the appropriate food group. Ask:
  
• What group provides the most calcium? The Milk Group.
  
• What is the easiest way to get calcium each day? Drinking milk, and eating cheese and yogurt—foods from the Milk Group.
  
• Discuss how Combination Foods can be a good or rich source of calcium. Ask students:
  
• What is a Combination Food? Combination Foods contain foods from two or more food groups.
• State that a beef taco is an example of a Combination Food. Ask students:
  
• What food group does the taco shell belong to? Grain Group.
  
• The tomato and/or lettuce? Vegetable Group.
  
• The cheese? Milk Group.
  
• The ground beef? Meat and Bean Group.
  
• What is the benefit of eating Combination Foods? Since Combination Foods contain two or more food groups, they provide a variety of nutrients, including calcium, in one single meal.

Have students come up with a list of Combination Foods and identify whether or not the foods provide calcium. Examples include cheese pizza, taco, cheeseburger, and macaroni and cheese.

Going Further

Discuss calcium-fortified foods.

• Many foods (normally poor sources of calcium) have calcium added. While these foods can help people meet their calcium needs, they are not substitutes for the recommended servings from the Milk Group.
• Dairy foods contain natural components that help with calcium absorption that are not found in other foods.
• Milk provides the complete package of nutrients for building strong bones that is superior to fortified foods. Remember, these nutrients are vitamin D, vitamin A, phosphorus, magnesium, and protein.

Session Four

• Distribute the completed It’s Just Another Day: Your Food Findings! worksheet from session one and Did You Feed Your Bones Today? worksheet. Have students circle the number of calcium points for each food they chose to eat on Did You Feed Your Bones Today? worksheet. Have students total the points for each section of the story.
• Explain that the points listed for each food identify the amount of calcium found in the food. In order to meet their daily calcium goal, they need to score at least 130 points. Poll students:
• How many scored 130 points? 120 points? 110 points? Less that 100?
• How many selected 4 servings from the Milk Group? 3 servings? 2 servings? 1 serving?
• Who needs HELP?
  
• Distribute Take Interest in Strong Bones worksheet and divide the class into groups of four. Have students brainstorm ideas that will help them get four servings of dairy everyday. Discuss the ideas with the rest of the class. Ask:
• How about a cup of milk with breakfast, lunch, or dinner?
• Vanilla yogurt with your strawberries or other fruits?
• Yogurt or string cheese for a snack?
• A grilled cheese sandwich for lunch?
• Some shredded cheese on your broccoli?
• A milk and fruit smoothie?
• A bottle of chocolate or strawberry flavored milk?
• Ask students to choose five ideas to fill the five slips. Have them answer the first three questions in class. For the next five days, ask students to follow their plan to build strong bones and record how their plan worked on the slip.
• At the end of the week, collect the slips and share the results. Discuss which ideas were most successful at increasing the number of servings of the Milk Group. Share how and why these plans worked and encourage the students to follow them.

Going Further

Beyond building strong bones, milk contains other nutrients that are essential for body functions and growth. Give each student the Improve Your Diet Quality with 3-A-Day of Dairy handout. Discuss the nutrients found in milk and other dairy products. Potassium is critical for regulating fluid balance and maintaining normal blood pressure. Vitamin B12 builds red blood cells that carry oxygen to muscles and keeps the nervous system healthy. Riboflavin, another B vitamin, helps change food into energy.

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