Bone is living tissue, and the skeleton your child builds in childhood and adolescence will be the foundation for their bone health for the rest of their life. According to the International Osteoporosis Foundation, up to 90% of peak bone mass — the maximum density and strength your bones will ever reach — is acquired by the age of 18.

This makes the window from birth to early adulthood the single most important period for calcium investment. The analogy often used is a bank account: every high-calcium meal is a deposit. Every calcium-poor year is a missed opportunity. Unlike most bank accounts, this one stops taking large deposits after the late teenage years.

The Indian context is particularly concerning. India has among the highest rates of vitamin D deficiency in the world — paradoxically, despite being a sun-rich country. Studies show that 50–90% of urban Indian children have insufficient vitamin D levels. Without adequate vitamin D, calcium cannot be effectively absorbed from the gut, no matter how much calcium is consumed.

The daily calcium requirements by age (ICMR 2020): 1–3 years: 600mg; 4–6 years: 600mg; 7–9 years: 800mg; 10–12 years: 1,000mg; 13–18 years: 1,300mg. One cup (240ml) of full-fat milk provides approximately 300mg of calcium. This means most children need 3–4 servings of dairy daily to meet requirements.

For children who do not consume dairy due to allergy, intolerance, or preference, excellent non-dairy calcium sources include: ragi (finger millet) — one of the richest plant sources at ~350mg per 100g; sesame seeds (til); amaranth (rajgira); drumstick leaves (moringa); soya milk (if fortified); tofu; chia seeds; and calcium-fortified plant milks.

Vitamin D works as calcium's essential partner. The best natural source is sunlight — 15–20 minutes of direct skin exposure (arms and legs) between 10am and 3pm, at least 3–4 times per week. Food sources include egg yolks, fatty fish, and fortified foods. Many paediatricians now recommend supplementation for children who get limited sun exposure, but this should be confirmed with a blood test.

Physical activity — particularly weight-bearing and impact activities — is the third pillar of bone health. Running, jumping, skipping, dancing, and sports all apply mechanical stress to bones that stimulates bone-building cells. Children who are physically active have measurably higher bone density. Screen time displaces both physical activity and outdoor sun exposure, compounding the risk.