Copyright 2012 . Sarah Toohey, All Rights Reserved.
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Calcium
Calcium is a vital nutrient, playing a significant role in the body’s intracellular processes. In conjunction with phosphorus, calcium is the principle component of our bones. It is important to understand the bones as reservoirs of calcium, not just ‘stilts’ our bodies are built on. Because calcium is essential on a cellular level, our hormones constantly regulate the amount of calcium in the bloodstream available for cellular processes. If it is not coming from the diet, our bodies quickly reach for their reservoirs, pulling calcium from the bones to keep levels where they need to be. The main hormone responsible for releasing calcium from our bones is parathyroid hormone. Vitamin D helps the body absorb calcium from the gut, taking it from what we eat. This is a balancing act. Parathyroid hormone isn’t ‘bad’ because it depletes our bones of calcium. It is simply doing its job to maintain calcium balance. An optimal diet and lifestyle gives us ample Vitamin D and Calcium intake to build up reservoirs: strong bones full of calcium.
The Impact of Exercise
It is important to note that exercise or physical strain on bones helps them to grow stronger. Increased bone mineralization is seen when a person exercises or puts force on the bones. This is important for all of us but particularly for children with special needs where physical activity is more difficult. For these children, physical therapy and regular exercise to the best of their ability is very important. It should also be noted that this can be taken too far: poor bone mineralization is part of the female athlete triad. An unreasonable amount of exercise, for women this would be in the range where periods have ceased, can cause a decrease in bone strength. I am not discouraging endurance athletics in women but I am saying these athletes should be carefully monitored and teenage girls, going through a critical phase of bone growth, should not be encouraged to exercise to the extent that they harm bone mineralization for life.
Calcium Needs
Age Calcium Intake (mg/day)
0-6 mo. 210
7-12 mo. 270
1-3 yrs. 500
4-8 yrs. 800
9-18 yrs. 1300
19-50 yrs. 1000
51 and up 1200
Sources of Calcium
Dairy really is the best source of calcium. Though bioavailability in high in vegetables, the actual content of calcium is quite low. Other options include fortified foods like orange juice and cereals that have been fortified with extra calcium. These are viable options. For children with milk protein allergy, it is important to lean on these sources. For children with lactose intolerance, it is important to remember that most can consume small amounts of milk, and may also tolerate it in different forms like yogurt or high fat forms like ice cream.
The following selection shows the calcium content of many common foods:
Food Serving Calcium (mg)
Whole Milk 1 cup 246
1% Milk 1 cup 264
Yogurt, nonfat 6 oz. 258
Cheese 28g 202
Salmon(canned) 3 oz. 203
Tofu ½ cup 204
Broccoli, cooked 1 cup 62
Baked beans 1 cup 127
Calcium fortified Orange Juice 1 cup 300
Fortified Cereals 1 cup 100
Source: Pediatric Nutrition Handbook, 6th Edition.
Matthew Toohey, MD, March 26, 2012.
Micronutrients
Nutrition