Various factors affect how much of the calcium you ingest really gets into your blood. Here are facts you should know to make the most of the calcium in your diet or any calcium supplements you take:
1. Stress from tension and worry can decrease calcium absorption. The calcium in the diet is excreted rather than used.
2. Labels on calcium supplements can be misleading. The figure that is important is the amount of elemental calcium provided by the supplement. This is the actual amount of useable calcium. The rest of the calcium in the tablet is coupled with a salt that makes it unavailable to the body. For example, calcium glutamate is only 9 percent elemental calcium. A 500 milligram tablet of calcium glutamate may contain only 45 milligrams of elemental calcium, even though you may have been led to believe that you are taking 500 milligrams of calcium. Calcium carbonate, on the other hand, is 40 percent elemental calcium; 500 milligrams of calcium carbonate would provide 200 milligrams of useable calcium. Labels on some supplements make this distinction, listing both the type of calcium compound in the supplement and the amount of elemental calcium provided. Other products are not as carefully labeled. Read labels carefully and compare several brands when you shop.
3. Calcium is best absorbed when taken in smaller amounts more frequently and with meals. For example, your body absorbs more calcium if you take one 250 milligram tablet twice a day rather than one 500 milligram tablet once a day. If a higher dose calcium tablet is a better buy, break it in half.
4. Dairy products are a rich source of calcium, and lactose, the sugar contained in milk, facilitates calcium absorption. However, chocolate milk is not a good source of calcium. Because chocolate contains calcium-binding oxalates, it can interfere with calcium absorption.
5. Soft drinks that contain citric and phosphoric acid can decrease the absorption of calcium. A 12-ounce cola may rob the body of 100 milligrams of calcium.
6. Vitamin C improves the absorption of calcium, which is why calcium-fortified orange juice makes sense.
7. High-fiber diets can interfere with calcium absorption, so best not to mix a high fiber meal with a high calcium one. If you do mix them, boost your calcium as you increase your fiber.
8. The calcium-to-phosphorus ratio of a food or supplement determines how much of the calcium is absorbed. The ideal calcium-phosphorus ratio is 2 to 1, close to the proportion found in human milk, which has an almost perfect calcium-to- phosphorus ratio of 2.3 to 1. The ratio in cow’s milk is 1.3 to 1. The higher the phosphorus content of the food, the more calcium is excreted in the urine, leading to a loss of calcium. Foods high in phosphorus (such as meat, poultry, corn, potatoes, beer, buckwheat) can interfere with calcium absorption.
9. The presence of estrogen facilitates calcium absorption, so women after menopause are at increased risk of calcium deficiency and therefore need to increase their daily intake of calcium.
10. You may read that vegans run the risk of calcium deficiency because the calcium in vegetables, like iron, is bound by the fibers and phytates (mineral-building chemicals in plants) in the vegetables and may interfere with calcium absorption. The theoretical worry may be balanced out by the lower phosphate content of vegetables, which improves calcium absorption, and by the fact that most people have the enzyme phytase, which breaks down the phytic acid in vegetables.
11. Couch-potatoism, or lack of exercise, may contribute as much, or more, to osteoporosis than lack of calcium. Weight-bearing exercise (just about any exercise except swimming or cycling) not only builds muscle, it builds bone.
12. Ignore what you read about losing bone mass while breastfeeding . After weaning, breastfeeding mothers regain the bone mass they may have lost. Some even get a perk by regaining more.