Dr Phil Kieran: Could my teenage son have brittle bones? 

Pic: iStock

My son, aged 15, fell off his bike three months ago and broke his arm. He was treated quickly in hospital and has made a full recovery. He has a good diet but does little exercise besides the cycle to and from school every day. Is there a possibility that he has brittle bones?

I’m glad to hear he made such a good recovery. Children often recover well from broken bones, frequently only breaking halfway through. Your question about bone strength is an interesting topic and one I spend a lot of time talking to young people about.

Bones are robust and light, but given the right impact, they can and do break. This force depends on the bone in question, the person’s age, and the type of impact. Falling from a moving bicycle can have a high impact on anyone, and I suspect most 15-year-olds are not travelling slowly.

Be assured: The fact that the bone broke is likely not an indication of abnormally weak bones.

Bone health is the result of many factors. One of the most important is calcium, which is found in many foods, most notably dairy products, and in many green vegetables. Calcium makes our bones and teeth hard, so getting enough of it in our diet is essential.

Teenagers need about 1,200mg of calcium daily, and adults need about 1,000mg. I strongly recommend that teenage girls watch their calcium intake carefully, as pregnancy and later menopause can weaken their bones.

To absorb calcium, we need vitamin D, which is made in our skin in response to the sun. Unfortunately, we don’t get a lot of sunshine in Ireland and from September to March, we naturally make almost no vitamin D. Taking a vitamin D supplement or foods fortified with vitamin D over the winter is recommended. Exercise will help increase bone strength too.

For this effect, we need to do weight-bearing exercise so walking, cycling, rock climbing, or weights can help build healthy bones. Also, being underweight can negatively impact bone strength, so we must encourage a healthy body image for all our children.

Your son has a healthy diet (so should be getting enough calcium), cycles to school every day (weight-bearing exercise), and is likely to have pretty good bone health.

‘Brittle bones’ can indicate various conditions, but it is unlikely any of these apply to your son. I would worry if he had broken a bone in a low-impact event, which this doesn’t sound like, or if he had multiple fractures without good reason.

Broken bones happen and are a consequence of an active life. The activity is more beneficial in almost all cases than the risk of injury, so encourage your son to keep up a healthy diet and broaden his horizons when it comes to exercise.

• If you have a question for Dr Phil, please send it to [e-mail]