According to the National Institute of Child Health and Human Development,
(NICHD), part of the National Institutes of Health (NIH): “Our nation’s youth stands in the middle of a calcium crisis. About half of all U.S. children less than 5 years of age don’t get enough calcium in their diet; and only 13.5 percent of girls and 36.3 percent of boys age 12 to 19 in the United States get the recommended daily amount (RDA) of calcium, placing them at serious risks of bone disorders both now and in the future.”
Calcium is a mineral essential for building healthy bones, including the jawbone, and teeth. It can also keep the gums healthy. (One study found that getting adequate levels of calcium in childhood may reduce the incidence of gum disease later in life). In fact, calcium plays an important role in almost every physiological function of the body. According to Robert Heaney, M.D., co-author of the Indiana Calcium Initiative, Consensus Statement, 2000, diseases associated with calcium-deficient diets include osteoporosis, adult, childhood and pregnancy-related high blood pressure, colon cancer, obesity, type II diabetes, polycystic ovarian disease, premenstrual syndrome (PMS), postpartum depression and kidney stone formation. All of these diseases are caused by a variety of factors, with low calcium intake being only one aspect involved in each condition.
Osteoporosis, which currently affects about 10 million Americans, causes gradual bone loss that proceeds so insidiously that it has been called “the silent killer”. The disorder causes a loss of normal bone density with thinning of bone tissue and the growth of small holes in the bone. This is frequently accompanied by pain, especially in the lower back; an increased proclivity for broken bones; and loss of body height. Two important factors that influence the incidence of osteoporosis are peak bone mass attained during the first two to three decades of life, and the rate at which bone is lost during the later years.
Because 90 percent of bone mass is established by age17, childhood and adolescence are critical times for bone development. According to the National Osteoporosis Foundation, the average woman has acquired a full 98 percent of her skeletal mass by age 20. Bones then continue to grow slightly more dense until age 30, when peak bone mass is reached. At this point, bone mass and density may remain steady, or it may begin to decline at a rate of up to one percent each year.
Several studies have shown a link between low calcium intake and an increased rate of fractures in adolescent boys and girls. However, a recent NICHD-supported study found that there is a “window of opportunity” to add to the development of bone mass during the teen years. Researchers found that supplementing the daily diets of girls ages 12-16 with extra calcium produced a 14 percent increase in their bone density in comparison with girls who did not receive supplements. If this increase could be maintained, its impact would be striking, since, for every 5 percent increase in bone density, the risk of later bone fracture decreases by 40 percent.
Duane Alexander, M.D., director of NICHD, says that “Prevention of osteoporosis and other bone diseases begins in childhood. With the low calcium intake levels we’re now seeing during these important bone growth periods, today’s children and teens are certain to face a serious public health problem in the future.”
To prevent this from happening, we need to take action quickly, for the health risks related to low calcium intake are not just years away. The number of fractures among children and young adults has increased. Pediatricians are also seeing the resurgence of rickets — a bone disease resulting from low levels of Vitamin D; rickets had become nearly nonexistent in the U.S. after vitamin D was added to milk in the 1950s.
What’s a parent to do?
In 1997, the government released revised guidelines, the Dietary Reference Intakes (DRIs), which set adequate intake values for calcium designed to lead to the fewest diet-related osteoporotic fractures in later life. Recommendations are broken down by age group, and are as follows:
Birth to six months: 210 mg.
6-12 months: 270 mg.
1-3 years: 500 mg.
4 -8 years: 800 mg.
9-18 years: 1300 mg.
Parents need to know that other factors affecting bone development include Vitamin D (which plays an important role in calcium absorption), and weight-bearing physical activity — such as walking, running and jumping.
Experts believe that calcium should be obtained from natural dietary sources whenever possible. Foods/drinks that have approximately 300 mg. of calcium per serving include:
—One cup (8 oz.) milk
—One cup calcium-fortified orange juice
—1 1?2 oz. cheddar cheese
— 1 cup yogurt
Other calcium rich foods include canned fish with bones, red beans, dried figs/prunes, broccoli, tofu, spinach, hazelnuts.
The National Institutes of Health designates dairy products as the preferred source of calcium, and encourages consumption of low-fat or fat-free milk rather than whole milk after two years of age. In addition to calcium, milk provides other essential nutrients — Vitamins D, A, and B12, potassium, magnesium, protein, phosphorus and riboflavin — which are essential for optimal bone health and human development.
A growing number of studies suggest milk offers superior bone-building benefits compared to supplements. A recent Chinese study looked at 649 girls, ages 12-14, and found that those who drank milk had denser bones compared to those who drank little or no milk. After accounting for all the factors that could affect bone mineral density, results indicated that milk was the only food group with a significant positive effect — leading the researchers to conclude that the positive effects of milk on bone density was most likely related to its integration of several nutrients, particularly vitamin D, calcium and protein.
For those children who require calcium supplementation, experts recommend that for optimal absorption, no more than 500 mg. of supplemental calcium should be taken at any one time. Parents of lactose-intolerant children should consult their child’s health care provider to find out the best way to ensure adequate calcium intake.
Further resources:
• The Internet is chock full of health and nutrition advice, and many reputable sites can be useful in educating parents and children about the importance of a well-balanced diet. The Nemours Foundation, which sponsors “KidsHealth”, has separate sites geared to parents, children and adolescents. An article available at the parents’ site
(http://kidshealth.org/breaking_news/calcium_crisis.htm) offers tips for parents, including:
— Giving your child milk (preferably 1% or 2% lowfat, or nonfat skim) milk instead of soft drinks and fruit drinks. If your child is lactose-intolerant, consider soymilk or a calcium supplement.
— Offering a variety of foods that contain calcium, including fortified food products such as breakfast cereals and orange juice. Because dieting teenage girls may avoid dairy products, believing they will make them “fat”, be sure that your teen is getting adequate calcium.
— Encouraging good exercise habits.
• NICHD, which sponsors a calcium education initiative called ‘Milk Matters’, recently expanded its Milk Matter Campaign and website (www.nichd.nih.gov/milk) to speak directly to children and their parents about calcium. The campaign offers a variety of free materials — brochures, booklets, coloring books, stickers and posters — and most are available in Spanish and English. The children’s and teens’ section provides an interactive way for kids to learn more about calcium, and includes games, quizzes and other activities related to calcium, milk and fun ways to build healthy bones and teeth.
• ‘Powerful Bones, Powerful Girls’: The National Bone Health Campaign, sponsored by the Centers for Disease Control and Prevention, the U.S. Department of Health and Human Services Office on Women’s Health, and the National Osteoporosis Foundation, is a multi-year campaign geared at promoting optimal bone health in girls 9-12 years old — by encouraging them to establish lifelong healthy habits, especially increased calcium consumption and physical activity to build and maintain strong bones. A colorful and interactive website (http://www.cdc.gov/powerfulbones) features “Carla”, a wide-eyed, curly-haired teenage girl, who invites kids to enter the site, solve “the crazy calcium caper”, and read “lots of cool information about how to be a powerful girl and take good care of your bones!” In addition to girls 9-12 years old, the campaign (and website) targets adults who influencegirls, including parents, teachers, coaches and youth group leaders.
