FACTS
Ninety-nine percent of the calcium is in the bones and teeth, while the remaining one percent is in the blood. Calcium is essential for many body functions, including regulation of the heartbeat, conducting of nerve impulses, stimulation of hormone secretions and clotting of blood, as well as for building and maintaining a healthy skeleton. If calcium levels in the blood drop to below normal, calcium will be taken away from the bone in order to maintain blood calcium levels. Therefore, it is important to consume enough calcium to maintain adequate blood and bone calcium levels.
It is recommended that adult men and women consume 1,000 – 1,200 mg/day. The best source of calcium is from the foods we eat because there are other essential nutrients that are found in high-calcium foods.
Table 1. Sources of calcium
Serving size
|
Calcium (mg)
| |
Milk & yoghurt
|
8 oz
|
300-450
|
Cheese
|
3 oz
|
300-450
|
Bones in canned sardines and salmon
|
3 oz
|
181-325
|
Calcium fortified foods (ie, orange juice, soymilk)
|
8 oz
|
200-300
|
Dark green, leafy vegetables
|
½ cup
|
50-100
|
Nuts and seeds
|
1 oz
|
25-75
|
Source: Mullins V, et al. Calcium Supplement Guidelines, The University of Arizona College of Agriculture
If you cannot consume enough calcium from your foods, supplements are a safe alternative. Calcium absorption is dependent on an adequate level of the active form of vitamin D. Vitamin D supplements, however, are usually not necessary as it is available in vitamin D fortified milk, foods such as fish and egg yolks, and exposure to sunlight by skin (15 minutes per day is enough to maintain an adequate vitamin D level).
Common calcium supplements include calcium carbonate and calcium citrate. Calcium carbonate is best absorbed when taken with food. Calcium citrate can be taken any time.
Table 2. Calcium Forms
Supplement Form
|
Percent Elemental Calcium
|
Comments
|
Calcium Citrate
|
21%
|
Best absorbed supplemental form of calcium. Does not require extra stomach acid to dissolve. Calcium citrate can come in colloidal form, a liquid form of calcium that may be less irritating to the intestinal wall.
|
Calcium Carbonate
|
40%
|
Most common type in the market. Usually requires extra stomach acid for digestion, and should be taken with a meal.
|
CLAIMED BENEFITS
- Bone health
- Prevention of bone loss due to calcium deficiency
- Treatment of osteoporosis in combination with other therapies
RIGHT AMOUNT
To avoid calcium toxicity, it is recommended that you do not take more than 2,500 mg of elemental calcium a day (from all sources combined). High calcium intakes can lead to constipation and increase the risk of kidney stones.
