Calcium is the most abundant mineral in the body. The bones and teeth contain more than 99 per cent of it. Calcium is also found in the blood, muscles, and other tissue.
Calcium in the bones can be used as a reserve that can be released into the body as needed. The bone itself undergoes continuous remodelling, with constant resorption and deposition of calcium into new bone. The balance between bone resorption and deposition changes with age.
Bone formation exceeds resorption in periods of growth in children and adolescents, whereas in early and middle adulthood both processes are relatively equal. Bones are always breaking down and rebuilding, and calcium is needed for this process.
In new updates to clinical guidelines for paediatric bone health recently published in Paediatrics Journal, by the American Academy of Paediatrics (AAP) Committee on Nutrition, the best way to promote bone health for your child is through diet.
In infancy, human milk or infant formula are the primary sources of calcium. Although formula-fed infants have higher calcium levels than breast-fed infants, no data indicates need for any additional benefit from supplements. Milk and other dairy products typically contribute 70 per cent to 80 per cent of dietary calcium. Green leafy vegetables, legumes, nuts, fruit juice, and some fortified breakfast cereals also contain calcium.
Declining milk consumption is an issue for both pre-adolescents and adolescents. Increased soda consumption is associated with decreased consumption of milk. Many teenage girls consider milk "fattening." 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.
Vitamin D is essential for calcium absorption; without it, only ten per cent to 15 per cent of dietary calcium is absorbed. The new guidelines encourage clinicians to ask their patients about what they eat and encourage them to eat more foods and beverages rich in calcium and vitamin D. Clinicians should also ask their patients about exercise and encourage activities such as walking, jumping, skipping, running, and dancing over swimming or bicycling.