Bones serve our bodies in two ways:
1. Bone serves a structural function in giving us a mobile skeleton which enables us to move and and also protects and supports vital parts of our body.
2. Bone also act as a reservoir by acting as a storehouse for essential minerals that our bodies need.
Bone is constantly changing, remodeling itself. It is a very dynamic and important tissue. Bone is always in a combination of 2 competing processes: forming new bone (bone formation) and breaking down bone (bone resorption). At different times in our lifespan, formation will dominate the process but at a certain point, resorption will outpace the formation processes and our bone density will reduce.
How well we take care of our bodies during those strong formation years will impact us later when resorption will dominate. There are several things that can be done to help our bones lay the strongest foundation possible but we have to grab the main window of opportunity for this biological timetable. This window is the first three decades of life with a strong focus on the adolescent years. By the time we reach 30 years of age, the resorption processes begin to have the upper hand.
There is growing concern over the health of bone in American culture. Most people have heard of osteoporosis and the impact this has on primarily older persons. Osteoporosis show itself later in life but its start actually lies in young adulthood. The more bone mass that we possess as a young adult provides us a safety net for higher bone mass to be sustained later in life and lessens the risk for fractures. Peak bone mass density (BMD) may be the single most important factor in the development of osteoporosis and the time to build peak BMD is before age 25!
Children build bones by getting good nutrition (adequate intake of calcium and Vitamin D – see chart at end of blog for recommendations) as well as being physically active. American children are not getting the critical elements needed to healthy bone growth. For example, only 4 out of 10 boys and 2 out of 10 girls (ages 12-19) consume the RDA of calcium (1300 mg/day). Only 19% of all high school students are physically active for 20 minutes a day. 61.5% of students (ages9-13) do not participate in any organized physical activity during non school hours and 22.6% do not engage in any free time physical activity.
Nutritional habits of adolescents also may include excessive intake of phosphorus in sources like colas/sodas and phosphorus promotes bone resorption not formation. Puberty and adolescence marks a biological timetable of rapid skeletal growth where the bones get longer as children gain height and then mineralize/fill in with strength which marks the density of the bone. Peak length happens first and peak density follows until around age 25-30 with a great majority of these processes happening early (12-20 year range).
Studies have shown that active adolescents have approximately a 10% greater bone density in young adulthood (age 20-30) compared to non active adolescents. Long term studies have even demonstrated that being active in adolescence provides a protective effect even 40 years later in females who are now going through menopause and its associated relationship to loss of bone mass.
The take home points in helping children and adolescents are:
1. Make sure your child is getting all the nutrients that are needed for good bone health (see chart below)
2. Encourage your child to be physically active.
Exercise prescription for children to build healthy bones is for high impact, weightbearing activities that allow for multidirectional and dynamic loads for 60 min at least 3x/week. Examples: jump rope, hopscotch, dancing, soccer, football, volleyball, gymnastics, weightlifting, weight bearing video games (not sitting), running, skipping, tennis and basketball. Swimming and bike riding, although great for other aspects of health, do not offer the same weightbearing impact needed for bone density building. Children should be encouraged to do many types of exercise.
A special note for children who may possess health conditions that impact bone health. Examples include genetic bone disorders (osteogenesis imperfecta), any chronic condition that affects absorption of nutrients or inhibits growth (Celiac disease, Crohn’s disease, cystic fibrosis, inflammatory bowel disease, chronic asthma, renal insufficiencies, cancer, conditions requiring high doses of steroids and eating disorders). These types of conditions may require specialized medical intervention. Immobilization conditions due to need for a wheelchair or bedridden due to neurological or orthopedic condition do not permit weight bearing activities that are needed. Special interventions with medications, standing devices and formal therapy may be necessary.
You are now prepared to help your children make vital “deposits” into their “bone bank account” before they will need to make “withdrawals” when they get older. The bigger the account, the fewer problems they will face.
Calcium dose recommendation chart
In their most recent guide from 2011, the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine suggests the following calcium and vitamin D intake levels per day.
Stage, age range Recommended calcium intake per day Recommended vitamin D intake per day
Infants, 0–6 months 200 milligrams (mg) 400 international units (IU)
Infants, 7–12 months 260 mg 400 IU
Children, 1–3 years 700 mg 600 IU
Children, 4–8 years 1,000 mg 600 IU
Adolescents, 9–18 years 1,300 mg 600 IU
Adults, 19–50 years 1,000 mg 600 IU
Older adults, 51–70 year 1,000 mg (men)1,200 mg (women) 600 IU
Older adults, 70+ years 1,200 mg 800 IU
KID FRIENDLY FOODS CONTAINING CALCIUM
Plain nonfat yogurt, 1 cup 452 mg
Plain low fat yogurt, 1 cup 415 mg
Swiss cheese, 1.5 oz 408 mg
Chocolate Milkshake 374 mg
American process cheese, 2 oz 348 mg
Fruit flavor low fat yogurt, 1 cup 345 mg
Mozzarella cheese (part skim), 1.5 oz 311 mg
Cheddar Cheese, 1.5 oz 306 mg
Skim milk, 1 cup 302 mg
1% milk, 1 cup 300 mg
2% milk, 1 cup 297 mg
Whole milk, 1 cup 291 mg
Soft serve ice cream, 1/2 cup 118 mg
Ice Cream, 11% fat, 1/2 cup 88 mg
Almonds, 1/3 cup 120 mg
Frozen cooked Okra, 1/2 cup 90 mg
Orange 52 mg
Enriched English muffin 96 mg
Pancakes made with milk (2, 4″ dia) 72mg
Hamburger bun 54mg
Baked potato with cheese 350 mg
Cheese pizza, 1 slice 220 mg
Small taco 109 mg
Other ideas to sneak more calcium in your children’s diet include: Add cheese to sandwiches, use cheese and crackers as a snack, prepare canned soups with milk instead of water, add nonfat dry milk to soups, stews and casseroles, add grated cheese to salads, choose calcium rich desserts like ice cream, frozen yogurt, cheese with fruit, custards and puddings made with milk, try calcium fortified orange juice and cereal products.