Of all minerals present in the body, calcium is the most prevalent. And, the body’s need for calcium is higher than that of any other vitamin or mineral because it plays a central role in many of your body’s most basic functions.
Ninety-nine percent of the calcium in your body is found in the bones and teeth where it is an essential part of bone structure. The remaining one percent of the body’s calcium plays a part in many vital life-sustaining roles such as muscle contraction (including heart pumping), blood clotting, the transmission of nerve impulses, the secretion of certain hormones and the activation of some enzyme reactions.
Because of calcium’s critical importance in virtually every cell, your body controls calcium levels closer than those of any other nutrient. If your calcium intake is too low to meet metabolic demands, your body’s control mechanisms will pull calcium out of your bones to maintain a healthy supply in the blood and to keep your cells functioning normally. In other words, the rest of your body takes precedence over your bones when it comes to available calcium. For this reason, inadequate calcium intake can lead to a weakening of the bones over time.
Osteoporosis, or fragile bone disease, is the most common skeletal disorder in the world. It affects some 25 million Americans and accounts for 1.5 million new fractures per year. Osteoporosis has been dubbed the "silent thief" because bone loss occurs gradually over time without warning signs or symptoms. Bone is a living tissue and is therefore turning over and renewing itself constantly. Bone loss occurs when the balance between bone synthesis and breakdown is upset and calcium is the most important nutritional factor that affects this balance.
Your optimal calcium intake varies throughout your life cycle according to age, physical condition and health status. But, in America today, about 100% of women and 90-95% of men over the age of 50 fail to consume the optimal level of dietary calcium. Younger women and teenage girls are also falling short on requirements with some 90% consuming sub-optimal amounts. This is of particular concern because the bones of females reach their peak calcium content at about 20 years of age and bone loss begins shortly thereafter.
Are you really getting what you’re consuming in terms of calcium?
Calcium absorption is an important feature to consider when you’re deciding on the potential nutritional benefit of a calcium source. Whether the calcium you consume comes from foods, beverages or supplements, it’s only as good as the amount that is absorbed and used by your body. And, not all calcium sources are created equal in terms of absorption. In addition, how and when you consume calcium can also affect its potential absorption. On average, the body absorbs only about 25% of the calcium contained in foods but there are some natural food sources such as broccoli, kale and Brussel sprouts that have been documented to have very good calcium absorption in the body. A study reported in the American Journal of Clinical Nutrition on the most common dairy products to measure their calcium absorption yielded the following results:
Milk: 26.7% absorbable calcium
Yogurt: 25.4% absorbable calcium
Chocolate milk: 23.2% absorbable calcium
Cheese: 22.9% absorbable calcium
Calcium absorption takes place in the acid-neutral environment of the small intestine therefore the solubility of the calcium source in an acid-neutral environment helps determine the level of absorption. Different sources of calcium used in supplements have varying solubility in this type of environment. In addition, the body’s pathways for absorbing calcium have their limits in terms of how much calcium they can handle at any one time so the smaller the amount of calcium you eat at one time, the greater your chances of absorption will be.