Calcium And Adolescents
is a mineral. It plays a crucial role in building healthy teeth and bones. Unfortunately, most adolescents do not eat enough high-calcium foods. That puts them at risk of developing osteoporosis
when they get older.
What food source is the nutrient found in?
About 75 percent of the calcium in the American diet comes from dairy foods, such as milk, yogurt, and cheese. These foods are best because they contain high amounts of calcium. For instance, 8 ounces of milk, 1 cup of yogurt, and 1.5 ounces of cheese each contain 300 mg of calcium. They also provide other nutrients that help the body better absorb calcium, such as vitamin D, potassium, and magnesium. Dairy products are a good source of protein
and riboflavin, which are needed for proper growth and development.
Vegetables, grains, and beans also provide calcium, but the calcium in these foods is not absorbed as well as the calcium in dairy foods.
Calcium may be poorly absorbed in these foods:
- spinach, sweet potatoes, and beans, which are high in oxalic acid
- unleavened bread, raw beans, seeds, and nuts
As a result, several servings of these foods are needed to provide the body with the same amount of calcium present in one serving of dairy products.
Extra calcium has been added to some foods. These include:
- breakfast cereals
- snack bars
It is not known how much of this added calcium is absorbed by the body. Limited studies of calcium-fortified orange juice suggest that the absorption rate is about the same as milk.
How does the nutrient affect the body?
Calcium is needed for building healthy teeth and bones. Strong bones enable a person to stay physically active all through his or her life. It also reduces a person's risk for osteoporosis
as he or she gets older.
During the teen years, physical activity and nutrition play a key role in hip development. This is the time when calcium is best absorbed and when most bones are formed. By the time a person reaches the age of 17, about 90 percent of his or her adult bone mass has been reached. To support the growth of strong bones, federal guidelines recommend that children between the ages of 9 and 18 consume 1300 mg of calcium each day. This equals more than four glasses of milk.
The gap between the amount of calcium that is recommended and the amount of calcium the typical child gets each day is large. The average child gets about 700 to 1000 mg of calcium a day, with values at the higher end of the range occurring in males. About 69 percent of the recommended calcium intake is consumed by girls, ages 9-13. Girls who are ages 14-18 consume about 55 percent of the recommended daily calcium intake. Teens may not get enough calcium because:
- they don't eat or drink enough dairy foods
- they don't eat enough fruits and vegetables
- they drink too many soft drinks
Another factor may be lactose intolerance
. A person with lactose intolerance cannot digest lactose, the natural sugar present in milk. Symptoms after eating dairy products include:
- stomach cramping
Lactose intolerance is most common in African Americans, Mexican Americans, and Asian Americans.
Children and teens who do not consume enough calcium are not able to achieve maximal bone mass. This puts them at risk for osteoporosis, which is brittle bone disease, when they get older. Osteoporosis affects more than 25 million Americans, most of them women. There is no cure for osteoporosis, so prevention is key.
Here are some ways that teens can increase their calcium intake:
- Eat or drink 3 to 4 servings of low-fat dairy foods, such as low-fat milk, yogurt, or cheese, each day.
- Eat at least one non-dairy source of calcium, such as green leafy vegetables or dry beans and peas, each day.
- Drink fewer soft drinks and substitute calcium-fortified juices or soymilk for some of the servings.
- Try substituting hard cheese and yogurt for some of the milk if they are lactose intolerant. These foods may be better tolerated. Lactose-free and low-lactose milks are also available. There is also medicine that can ease symptoms. Many teens with lactose intolerance
can drink small amounts of milk with a meal without a problem.
- Add some calcium-fortified foods to the diet. Choose healthy foods, such as 100% fruit juices or whole grain cereals.
- Watch the amount of salt consumed in snack foods, convenience foods, and fast foods, as it raises the amount of calcium lost in the urine. One study of teenage girls reported that for every 1000 mg of salt consumed, an extra 26 mg of calcium was removed from the body with urine.
- Spend time outdoors. Sunlight provides the body with vitamin D, which helps to maintain proper blood levels of calcium.
- Add nonfat dry milk powder to milk, cream soups, hot cereal, or other milk-containing products to increase calcium content.
A person who cannot or will not consume enough calcium from food should take a calcium supplement. For best absorption, no more than 500 mg should be taken at one time. As other nutrients affect calcium absorption, it may be wise to take a multivitamin and mineral supplement as well.
Weaver CM, Peacock M, and Johnston Jr. C. "Adolescent Nutrition in the Prevention of Postmenopausal Osteoporosis." The Journal of Clinical Endocrinology&Metabolism, 84(6):1839-1843; 1999.
Andon MB, Peacock M, Kanerva RL, DeCastro JA. Calcium absorption from apple and orange juice fortified with calcium citrate malate (CCM). Journal of the American College of Nutrition. 15:313-316; 1996.
National Institute of Child Health&Human Development. "Why Milk Matters: Questions and Answers for Professionals." August 1998.
Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride, The National Academy of Sciences, 1997.
American Academy of Pediatrics. "Calcium Requirements of Infants, Children, and Adolescents (RE9904). Policy Statement. Pediatrics. 104(5): 1152-1157; November 1999.
Lyritis, GP, Schoenau, E, Skarantavos, G. Osteopenic syndromes in the adolescent female. Annual N Y Academy of Science. 2000;900:403-8.
American Dietetics Association Annual Meeting. "Meeting Calcium Needs on Plant-based Diets". October, 1996.
ADA Website: Calcium.