The best way to promote bone health for children continues to be through diet, the American Academy of Pediatrics (AAP) Committee on Nutrition says in its updated clinical guidelines for pediatric bone health.
The update reflects the AAP's decision to endorse the higher vitamin D and calcium recommendations made by the Institute of Medicine (IOM) in 2011. The report replaces the AAP 2006 clinical report on calcium intake and its 2008 report on vitamin D deficiency, both of which were retired when the AAP endorsed the IOM report.
The report offers clinical guidance for pediatric bone health from birth through adolescence and includes discussions of weight-bearing exercise, diet, supplements, screening, and intervention. Neville H. Golden, MD, the Marron and Mary Elizabeth Kendrick Professor in Pediatrics, Stanford School of Medicine, and chief of the Division of Adolescent Medicine, Lucile Packard Children's Hospital, Palo Alto, California, and the AAP Committee on Nutrition, published the guidelines online September 29 in Pediatrics.
In infancy, human milk or infant formula are the primary sources of calcium. The recommended dietary allowance (RDA) from birth through age 6 months is 200 mg calcium per day, increasing to 260 mg from 6 to 12 months of age. Although formula-fed infants have higher calcium levels than breast-fed infants, no data indicate there is any additional benefit for these elevated calcium levels, the authors write.
Toddlers need 700 mg calcium daily through age 3 years, increasing to 1000 mg daily from age 4 years through age 8 years and 1300 mg daily for children aged 9 to 18 years.
Milk and other dairy products typically contribute 70% to 80% of dietary calcium, the authors note. An 8-ounce glass of milk provides 300 mg of calcium, as does a cup of yogurt or 1.5 ounces of cheese. Green leafy vegetables, legumes, nuts, fruit juice, and some fortified breakfast cereals also contain calcium. Although bioavailability of calcium from vegetables is high in general, the report states, it takes a lot of vegetables to meet the daily calcium requirement, and oxalates in some vegetables, including spinach, collard greens, and beans, reduce calcium bioavailability. In addition, diets low in protein may predispose children to reduced calcium retention.
Declining milk consumption is an issue for both preadolescents and adolescents. In 2011, only 14.9% of high school students drank 3 or more 8-ounce servings of milk daily, and only 9.3% of girls drank that much milk. Increased soda consumption is associated with decreased consumption of milk.
On average, adolescent girls consume only 876 mg calcium daily, which is 67% of their RDA. Fewer than 15% of adolescent girls meet the RDA for calcium. Many teenage girls consider milk "fattening," although, the authors note, "one 8-oz serving of skim milk contains no fat and only approximately 80 kcal, approximately the same caloric content as an apple. In contrast, a can of soda contains 140 kcal. Furthermore, milk provides protein and a number of important nutrients other than calcium, including vitamin D, phosphorus, and magnesium, which are important in bone health."
Milk alternatives, such as soy-based or almond-based beverage, are also at a disadvantage to milk: both have reduced levels of bioavailable calcium per glass than milk, even when calcium-fortified, the authors write.
A recent meta-analysis looking at the use of calcium supplements on bone mineral density (BMD) in children found that calcium supplements failed to improve BMD in the lumbar spine or femoral neck and produced only a small effect on upper-limb BMD.
"The investigators concluded that, from a public health perspective, calcium supplementation of healthy children is unlikely to result in a clinically significant reduction in fracture risk," the authors write.
Vitamin D is essential for calcium absorption; without it, only 10% to 15% of dietary calcium is absorbed. In 2011, the IOM boosted the RDAs for vitamin D. From birth to 12 months, infants need 400 IU vitamin D daily. From age 1 year through adolescence, the amount rises to 600 IU. Although vitamin D can be synthesized from sunlight, sunscreen use and reduced outdoor playtime have reduced sunlight exposure. In addition, anyone north of 33 degrees latitude (roughly, any area north of Louisiana) will not have adequate sun exposure in winter, even if they are outdoors.
Breast-fed infants should be supplemented with vitamin D if the mother is not taking vitamin D supplements of approximately 6000 IU daily. Breast-fed and partially breast-fed infants should be supplemented with 400 IU vitamin D per day, starting a few days after birth and continuing until they are weaned and drinking at least 1 L/d of vitamin D–fortified infant formula or cow milk. Children older than 1 year who are obese or receiving anticonvulsant, glucocorticoid, antifungal, or antiretroviral medication may require 2 to 4 times more than the 600 IU vitamin D daily, but there are no definitive recommendations for these children at this time.
In addition, the committee recommends:
Clinicians should ask their patients about what they eat and encourage them to eat more foods rich in calcium and vitamin D.
Clinicians should encourage increased dietary intake of foods and beverages high in calcium and vitamin D.
Clinicians should ask their patients about exercise and encourage activities such as walking, jumping, skipping, running, and dancing over swimming or bicycling.
There is insufficient evidence to recommend universal vitamin D screening; screen only children and teenagers with conditions associated with reduced bone mass or with recurrent low-impact fractures.
Consider the use of dual-energy X-ray absorptiometry screening only in the presence of medical conditions associated with reduced bone mass or in children and teenagers with clinically significant fractures sustained after minimal trauma.
Consider dual-energy X-ray absorptiometry for adolescent female athletes who have been amenorrheic for more than 6 months or who fit the "female athlete triad" of low energy availability, menstrual dysfunction, and reduced bone mass density. There is no evidence supporting the use of oral contraceptives to increase bone mass in those with anorexia nervosa or "the female athlete triad."
Restrict the use of bisphosphonates to children with osteogenesis imperfecta and "conditions associated with recurrent fractures, severe pain, or vertebral collapse."
The authors have disclosed no relevant financial relationships.
Pediatrics. Published online September 29, 2014.
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Cite this: Guidelines: Diet Is the Best Source of Calcium for Children - Medscape - Sep 29, 2014.