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Calcium and the Adolescent Athlete by Althea Zanecosky, MS, RD, LDN - June 2003

Written by Althea Zanecosky, MS, RD, LDN

Calcium is one of the studied minerals and the fifth most common element in the human body. Ninety-nine percent of calcium is in bones and teeth with the other one percent other cells and tissues. The accumulated of calcium in the bone is most critical during adolescence. This mineral also plays a crucial role in the physiology of the exercising muscle as it is used for the transmission of nerve impulses, maintenance and function of cell membranes and activation of enzyme reactions hormone secretions. But unlike other minerals, the effects of a low-calcium diet are not often obvious without a bone density test and may not affect sports performance until a stress fracture results.

The recommended intake (DRI) for calcium in teens ages 13 to 18 is 1,300 milligrams a day. Yet only 14 percent of teen girls and 35 percent of teen boys are meeting the former 1989 Recommended Dietary Allowance of 1,200 mg daily. This low calcium intake, especially by females, requires special attention by health and sports professionals.

The adolescent athlete most at risk for low-calcium status is the female who participates in sports that are common in the “female athlete triad.” Excessive training and high expectations of a physical appearance that promote under-nutrition contribute to the development of the triad, which consists of disordered eating, amenorrhea and bone loss. The greatest incidence of female athlete triad is in aesthetic and weight dependent sports such as endurance running, gymnastics and figure skating.

Often high school athletes (and adolescents in general) will do whatever is necessary to achieve their goals without thinking about the consequences. Most athletes want to get faster and leaner. Many adolescent females believe that high-calcium foods are fattening and will get in the way of their athletic goals and so avoid them. And teenagers eat out of the home for much of their day and may choose foods like soft drinks, which not only do not contain calcium but may interfere with its absorption.

Making adolescent athletes aware of the immediate consequences of low bone density (stress fractures, impared muscle contraction) may help improve calcium nutrition. While calcium can be found in a variety of foods, including vegetables, grains and dairy products, the 1994 NIH Consensus Conference on Optimal Calcium Intake designated dairy products as the preferred source of calcium. The NICHD has selected low-fat or fat-free milk as the best source of calcium because it has high calcium content and the calcium can be easily absorbed by the body.

Here are suggestions well accepted well by teen athletes that can help increase calcium intake. Note that they can choose regular fat and low fat calcium sources depending on their weight and calorie needs:

Have yogurt for breakfast or a snack
Drink calcium-fortified orange juice
Add cheese to a sandwich, burger or tortilla
Drink low-fat chocolate milk instead of soda
Have pudding for a snack or dessert
Make a smoothie with fruit, ice and milk
Add tofu made with calcium to stir-fry and other dishes
Top salads and soups with low-fat shredded cheese
Pour milk over cereal for breakfast or a snack
Serve broccoli or cooked dry beans as a side dish.

From: Ideas for High Calcium Meals and Snacks in the American Dietetic Association’s Complete Food and Nutrition Guide

References

USDA Continuing Survey of Food Intakes by Individuals, 1994, Table 3.

NIH Consensus Conference Statement: Optimal Calcium Intake, June 6-8, 1994; 12(4): 24.

Resources

Why Milk Matters Now For Children and Teens
http://www.nichd.nih.gov/milk/milk_facts.htm
Position paper - Female Athlete Triad
American College of Sports Medicine
http://www.acsm-msse.org/