Before the bones grow old

I have watched our children grow taller, outgrow their shoes and move from one school year to the next. Our youngest is now even taller than me.

As parents, we wistfully observe these changes. We nurture them as they transition from one age to the next, dutifully taking them to their pediatrician for checkups and vaccinations. Yet we cannot see the work going on inside them: the skeleton that is building the bone that must support them throughout their lives.

Bone is living tissue, constantly breaking down and renewing, which is a normal process for growth. During childhood and adolescence, however, the body produces bone faster than it removes it. The greatest amount a person eventually develops is called peak bone mass — one of the strongest foundations of lifelong bone health.

Puberty is particularly important. Research following young people from childhood to adulthood found that approximately 39 percent of the total bone in the body is accumulated during the four years surrounding their most rapid growth spurt. Depending on the skeletal site, peak bone mass is generally reached by the late teens or early 20s.

This accrual of bone is important to prevent the weakening of bones as one ages. The condition in which bones become too weak and prone to breakage is called osteoporosis. Although it is often thought of only in older persons, prevention must begin in childhood — during ordinary days at home, at school and during sports.

Genes strongly influence bone strength, but lifestyle matters. We cannot change inherited genes, but we can help create conditions in which bones grow well. Modifiable factors may account for 20 percent to 40 percent of peak bone mass.

Food is one such factor. Healthy food choices for our children are the building blocks of healthy bones. Calcium supplies essential minerals, vitamin D helps the body absorb it and protein supports the framework of bone. Milk, yogurt, cheese, tofu, beans, calcium-fortified foods, leafy vegetables and small fish eaten with their bones can contribute. Supplements may help when intake is inadequate or deficiency is documented, but they cannot replace balanced meals.

Vitamin D can be taken as a supplement, but it is also made in the skin when exposed to the sun. The timing matters, however. The best time of the day for this is 10 a.m. to 2 p.m., without any shade, sunscreen or protective clothing. While this is good for vitamin D synthesis, prolonged exposure also increases the risk of skin cancer. Limit the amount of time spent in the sun during this period of the day to only five to 15 minutes.

It is also wise to avoid excessive salt and caffeine. The kidneys excrete sodium and calcium together, so a high-sodium diet can increase the amount of calcium lost in urine. This does not mean eliminating all salt, but limiting heavily salted snacks and chips, instant noodles, processed meats and highly processed food.

Caffeine’s effect on calcium is smaller and the evidence is less consistent, so an occasional caffeinated drink is unlikely to weaken healthy bones. However, high intake may temporarily increase calcium loss, and soft drinks, coffee or energy drinks may displace milk and other more nutritious beverages. Caffeine can also disturb sleep, which growing children and teenagers need. Water and calcium-rich beverages are better everyday options.

Bones also need movement to promote growth. Running, jumping, dancing, sports such as basketball and tennis, and similar activities stimulate bone development. Exercises using body weight, bands or supervised weights also help. Guidelines recommend that young people average at least 60 minutes of moderate-to-vigorous activity daily, including vigorous and bone- and muscle-strengthening activity on at least three days a week.

Hours spent studying, gaming, scrolling or watching videos can quietly replace active play. Exercise should never be a punishment for eating or merely a way to lose weight. It should be part of becoming stronger, more capable and healthier.

We must pay attention when a young person becomes overly focused on weight. Restrictive eating, skipped meals, excessive training and rapid weight loss can deprive the skeleton of energy and nutrients. In girls, irregular or absent menstruation can be an important warning sign — not an achievement or an acceptable consequence of athletic training. In both girls and boys, inadequate nutrition can impair bone health and increase the risk of sports injuries.

Parents, coaches, teachers and doctors should take recurrent stress fractures, persistent bone pain, delayed puberty, menstrual changes and unhealthy eating behaviors seriously. The answer is not necessarily to stop all activity, but to restore adequate nutrition, adjust training and seek medical guidance.

Old age may seem far away to a child, and children should not have to worry about osteoporosis. Our role is to make nourishing food available, encourage varied activity, protect time for sleep and recovery, and teach them to respect rather than punish their bodies.

The bones that will carry our children through adulthood are already taking shape. Long before their bones grow old, we have the opportunity to help them grow strong.

The Osteoporosis Society of the Philippines Foundation Inc. will hold its Annual Convention in Baguio City on 5 October 2026, at Venus Parkview Hotel, bringing together healthcare professionals committed to advancing bone health across the lifespan.