Calcium is essential in muscle contraction, oocyte activation, building strong bones and teeth, blood clotting, nerve impulse transmission, regulating heartbeat and fluid balance within cells.
Calcium is an extremely important component of a healthy diet. A deficit can affect bone and tooth formation, while over retention can cause kidney stones. Vitamin D is needed to absorb calcium. Dairy products, such as milk and cheese, are a well-known source of calcium. However, some individuals are allergic to dairy products and even more people, particularly those of non-European descent, are lactose-intolerant, leaving them unable to consume dairy products. Fortunately, many other good sources of calcium exist. These include: seaweeds such as kelp, wakame and hijiki; nuts and seeds (like almonds and sesame); beans; amaranth; collard greens; okra; rutabaga; broccoli; kale; and fortified products such as orange juice and soy milk. Calcium has also been found to assist in the production of lymphatic fluids.
Calcium is essential for the normal growth and maintenance of bones and teeth, and calcium requirements must be met throughout life. Requirements are greatest during periods of growth, such as childhood, during pregnancy and when breast-feeding. Long-term calcium deficiency can lead to osteoporosis, in which the bone deteriorates and there is an increased risk of fractures. Adults need between 1,000 and 1,300 mg of calcium in their daily diet.
Calcium is found in significant amounts in many foods, including broccoli, kale, dandelion greens, collard greens, almonds, sesame seeds, blackstrap molasses, beans, and fortified beverages such as soy milk and orange juice. The calcium content of most foods can be found in the USDA National Nutrient Database.
Dairy products (such as milk, yogurt and cheese) do contain calcium, however they are not recommended as a dietary source because they contain a significant amount of saturated fat, which can contribute to cardiovascular disease.
The calcium content of dairy products is also misleading because most of the calcium is used by the body in the digestion of milk protein (casein). This can lead to calcium deficiency and osteoporosis.
However, calcium in dairy products is usually much more absorbable to human body than other sources of calcium such as plant based or dietary supplements.
Other factors besides poor diet also cause osteoporosis. After age 35, bone density naturally decreases. This is due in part because the body produces less estrogen and testosterone, hormones that control how fast the body uses calcium. Less hormones in the system mean less calcium in the bones and the possibility of greater bone loss.