Making healthy food choices involves knowing which foods to eat when and knowing the best way to get the vitamins and minerals our bodies need to function optimally. Our bones are an extremely important part of our body since they protect our organs, manufacture red blood cells, provide a place for muscles to connect, and provide the framework for our bodies.
As was discussed in a previous post, Dancers and Bone Health, bone tissue is constantly being renewed until the age of about 35 when bone building, or modeling, begins to slow down. At that time, our bodies have to depend upon the bone tissue that was amassed during the adolescent years to keep the bones healthy and strong.
Studies have found that dancers’ bone mass measurements, or bone mineral density values, are below what is expected and can cause stress fractures. This connection is discussed in detail in the post Why Dancers May Be At Risk for Stress Fractures and Osteoporosis. In addition to engaging in weight bearing activity to increase bone mineral density, dancers need to be concerned about the amount of calcium they ingest.
Calcium does many jobs in the body. It aids in muscle contractions, sending messages throughout the nervous system, and regulating hormone and enzyme levels, but its main job is to develop strong bones. Most dancers do not get enough calcium simply because they restrict caloric intake, and the foods that contain the most concentrated amounts of calcium tend to be high in calories.
During the teen years, calcium intake should be about 1300 mg/day, while adults should ingest between 1000 and 1300 mg/day. An important thing to remember is that calcium absorption is aided by vitamin D. Sunlight is the best source of vitamin D, but, unfortunately, our necessary use of sunblock prevents us from absorbing it.
The best way to meet our calcium and vitamin D needs is through dairy products like low-fat milk, yogurt, or cheese. A 1996 study found that calcium fortified orange and apple juices are also good sources of readily absorbable calcium. (1)
Almond milk is a good source of calcium for those who need to avoid dairy, providing more calcium per serving than dairy milk, but it does not contain vitamin D. Other dietary sources of calcium are salmon with bones, tofu, almonds, broccoli, kale, and spinach.
While calcium intake can also be boosted with supplements, it is important to know that a study conducted in 2007 found that those who ate calcium rich foods had higher bone density values than those who relied upon calcium supplements. (2)
Calcium supplements are available as calcium citrate and calcium carbonate. Calcium citrate is 21% calcium and easily absorbed by the body. Calcium carbonate is 40% calcium but relies upon stomach acids to help absorption and needs to be taken with food. It is also important to know that calcium in absorbed best in doses equal to or less than 500 mg at a time and that the body’s ability to absorb calcium decreases with age. (3)
Low bone mineral density is a problem because it leads to weakened bones, stress fractures, and osteoporosis. It is important for dancers to amass as much bone tissue as possible when they are young, and carefully monitoring their calcium intake is an important part of that process.
(1) Andon, M.B., Peacock, M., Kanerva, R.L, & DeCastro, J.A. (1996). Calcium absorption from apple and orange juice fortified with calcium citrate malate. Journal of American College of Nutrition, 15(3), 313-6.
(2)Napoli, N., Thompson, J., Civitelli, R., Armamento-Villareal, R.C. (2007). Effects of dietary calcium compared with calcium supplements on estrogen metabolism and bone mineral density. American Journal of Clinical Nutrition, 85(5), 1428-33.
(3) Office of Dietary Supplements National Institutes of Health. (2012). Calcium [Fact Sheet]. Retrieved from http://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/