Calcium is the most abundant mineral in the body and is essential for bone health, blood clotting, proper muscle and heart functioning and proper nerve transmission. The daily Recommended Dietary Allowance, or RDA, for calcium for adults aged 19 to 50 is 1,000 mg. Calcium is mainly found in dairy products, with 8 oz. of nonfat milk containing 296 mg, or 30 percent of daily requirements. Calcium is also found in tofu, fortified cereals and orange juice and dark green, leafy vegetables.
Calcium Absorption
Calcium is absorbed in the small intestine and into the bloodstream. Calcium absorption is dependent on an adequate level of Vitamin D, so it is often recommended that the two nutrients are taken together. After absorption into the bloodstream, only 1 percent is functionally useful in the body, while the other 99 percent is stored in the bones and teeth. Bones are constantly changing and absorbing calcium; however, in cases of malabsorption, calcium levels in the blood are low, and calcium will be taken from the bones to make up for it.
Causes of Low Calcium Levels and Malabsorption
Low calcium intake may be due to lactose intolerance or lack of a balanced diet. Excess calcium excretion, caused by excess protein or salt in the diet, may also be to blame. Lastly, some compounds found naturally in foods inhibit calcium absorption, and should therefore not be consumed at the same time as a high-calcium meal or supplement. These include oxalic acid, phytates and tannins, which are found in chocolate, plant foods and teas, respectively. Fiber supplements, laxatives and medications, such as steroids, and anticonvulsants also inhibit calcium absorption.
Consequences of Malabsorption
Low serum calcium can cause muscle spasms, stunted growth, irregular heart rate and high blood pressure. Additionally, low serum calcium can cause bone to be broken down in order for calcium to be pulled from it to increase serum levels. If more bone is consistently being broken down than is being built over a period of time, osteoporosis and low bone mass can result. Osteoporosis is a serious condition that increases the risk for fracture and loss of height.
Calcium Supplementation
If you are concerned about your calcium intake, talk to your doctor about taking a supplement. Many types of calcium supplements are available, including pills and chewable varieties. Always be sure to read the instructions on the bottle, as some must be taken with a meal; the acidic environment created by digestion is necessary to break down these supplements. Additionally, your body cannot absorb more than 500 mg at one time; if you require a larger dose than this, split it into multiple doses each day.
Member Comments