A moderate increase in daily protein consumption is all that's recommended by most sports nutritionists. However, as we pointed out earlier, avoid powdered protein supplements in favor of protein from food sources themselves. In any case, make sure your daughter is eating foods rich in iron. As a general rule, female athletes should have their iron status assessed before the season and then rechecked periodically. They need supplementation if there's evidence of a deficiency.
Some pediatricians recommend a daily iron supplement as a preventive measure.
If your teenager participates in intensive athletic training and competition, he'll probably experience a loss of water, sodium, and potassium, particularly during hot weather. As a general rule athletes should be well hydrated before an event and then should ingest small amounts of water throughout the activity. Finally, if your teenage athlete insists on giving vitamins a try, remind him that ingestion of excessive amounts of vitamins A and D can cause serious side effects, including brain swelling and liver or bone damage.