BY JILL CASTLE, MS, RDN of USASWIMMING.ORG
Nutrition plays a key role in performance and recovery. But for the young swimmer, it also supports growth and development. While there are important nutrients for swimming, such carbohydrates and protein, there are also micronutrients that may be at risk for deficiency, like iron, calcium, and vitamin D.
Of course, any nutrient can fall short of needs if the diet is inadequate compared to the requirements. Deficiencies should always be addressed in the growing athlete.
Three nutrients – iron, calcium and vitamin D—stand out as high-risk nutrients for the young swimmer. One, because they are already known to be deficient in children and teens, in general, and two, because they may be harder for the growing athlete to get enough. Here’s the lowdown on each nutrient, including recommended levels of intake, and food sources:
IRON
Iron carries and stores oxygen, which occurs at a higher level during periods of growth (read: childhood and adolescence). Female athletes, in particular, are at greater risk for this deficiency due to menses and exercise.
According to the 2010 Dietary Guidelines for Americans (DGA), 9% of 12-49 year-old women are iron-deficient. Swimmers who cut back on their eating or consume a vegetarian diet are at increased risk for iron deficiency.
Requirements:
4-8 year olds: 10 mg/day
9-13 year olds: 8 mg/day
14-18 year olds: 15 mg/day (females); 11 mg/day (males)
Iron comes from animal and plant sources, with animal sources being more efficiently absorbed in the body. The less efficient absorption of plant iron can be enhanced by vitamin C-containing foods like citrus fruit and juices.
Food Sources: beef, ground beef, dark meat turkey and chicken, canned light tuna in water, iron-fortified cereals, instant oatmeal, enriched bagels and breads, black beans, white beans, spinach and raisins
CALCIUM
Calcium is needed for normal bone development and strength, and is required for muscle contraction. All children and teens are at risk for calcium deficiency, but especially teens because they tend to eat and drink less dairy products as they age. Ironically, this is the time when they need calcium the most! Peak bone formation occurs in the teenage years and is completed in the early 20’s.
Requirements:
4-8 year olds: 1000 mg/day
9-13 year olds: 1300 mg/day
14-18 year olds: 1300 mg/day
Food sources: ready-to-eat cereals, calcium-fortified orange juice, cow’s milk, soymilk, yogurt, cheese, salmon, tofu, frozen yogurt, vanilla ice cream, cottage cheese, turnip greens, kale, Bok choy, broccoli, and white bread (calcium-fortified).
VITAMIN D
Vitamin D partners with calcium to build bones. It has also been identified in the prevention of cancer, heart disease, autoimmune disease and infectious disease. Sunlight activates vitamin D in the skin, but sunscreen, cloud cover, dark-colored skin, and other factors may limit its effectiveness as a source of vitamin D.
Requirements:
All kids and teens need 600 IU/day.
It’s not easy to meet vitamin D requirements because there are few foods that are rich sources of this nutrient, and the obvious foods like dairy products aren’t always consumed in the needed amounts (6 cups of milk equals 600 IU vitamin D). The combination of vitamin D-rich foods and sunshine are key to making sure the swimmer gets enough. For swimmers who practice indoors, getting adequate vitamin D from food (or a supplement) is critical.
Food sources: sockeye salmon, smoked salmon, canned tuna, vitamin D-fortified orange juice, milk, soymilk, rice drink, cooked pork, fortified ready-to-eat cereals, mushrooms, Canadian bacon, and eggs.
Iron, calcium and vitamin D are essential to the growing swimmer’s health and wellness, not to mention his athletic performance. Keep these three nutrients top of mind and you may avoid some significant roadblocks to training along the way.
Jill Castle, MS, RDN is a childhood nutrition expert and co-author of Fearless Feeding: How to Raise Healthy Eaters from High Chair to High School (www.fearlessfeeding.com). She is the creator of Just The Right Byte (www.justtherightbyte.com), and is working on her next book, entitled Eat Like a Champion: Performance Nutrition for Your Young Athlete. She lives with her husband and four children in New Canaan, CT.
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