First, the thing that matters more
Bone is built when the body has spare energy to build with. If a training teenager is not eating enough overall, perfecting calcium and vitamin D will not fix bone health. Get the meals and snacks around training right first.
With that in place, these two nutrients do genuinely matter, and they are the ones most often short in teenage diets.
Calcium: how much and from where
Requirements are higher in the teenage years than in adulthood, at roughly 1000mg a day for this age group. In practice that is around three to four servings of calcium-rich food daily, which is easy with dairy and easy to miss without it.
| Food | Approximate calcium |
|---|---|
| 200ml glass of milk | ~240mg |
| 150g pot of yoghurt | ~200mg |
| 30g cheddar | ~220mg |
| Fortified plant milk, 200ml | ~240mg, only if fortified |
| Tinned sardines, 100g | ~380mg |
| Cooked kale, 100g | ~150mg |
| Fortified breakfast cereal, per bowl | Varies, check the label |
Rough calcium content of everyday foods
The dairy-free trap
Plenty of teenagers cut out dairy, sometimes for good reasons and sometimes as a general idea about healthy eating. Plant milks vary hugely: some are fortified with calcium to match dairy, others contain almost none, and organic versions often are not fortified at all.
If dairy is out, check the label for added calcium, and include tinned fish with bones, tofu set with calcium, fortified cereals and leafy greens.
Vitamin D in the UK
Vitamin D helps the body absorb calcium. Between about October and March, UK sunlight is not strong enough to make it, and very few foods contain much. Official UK advice is that everyone considers a daily 10 microgram supplement through autumn and winter.
For athletes training indoors, covered up outdoors, or with darker skin, it is worth considering year-round, and a GP can check levels if there have been bone injuries.
The simple version
Three or four calcium-rich foods a day, plus a 10 microgram vitamin D supplement from October to March.
What not to bother with
- High-dose calcium supplements without advice, food sources are better and safer.
- Very high-dose vitamin D, more is not better and can be harmful.
- Collagen, greens powders and bone-health blends marketed at teenagers.
- Protein shakes bought in place of meals, food does this job better.
When to ask for a blood test
Worth asking a GP if there has been a stress fracture or repeated bone injury, if periods are absent, if she is very restrictive with food, or if fatigue is persistent. Ask about vitamin D and iron together, they often travel with each other.