Calcium Citrate Malate is a water-soluble calcium supplement. It is the calcium salt of citric acid and malic acid.

Calcium citrate malate's bioavailability stems from its water-solubility and its method of dissolution. When dissolved, it releases calcium ions and a calcium citrate complex. Calcium ions are absorbed directly into intestinal cells, and the citrate complex enters the body through paracellular absorption.

Nutrition

Calcium is an important component of a   healthy diet. A deficit can affect bone and   tooth formation, while overretention 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 nonIndo-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); blackstrap molasses; beans; oranges; amaranth; collard greens; okra; rutabaga; broccoli; dandelion leaves; kale; and fortified products such as orange juice and soy milk. The calcium content of most foods can be found in the USDA National Nutrient Database.^[2]

Calcium is essential for the normal growth and maintenance of bones and teeth, and calcium requirements must be met throughout life. Long-term calcium deficiency can lead to osteoporosis, in which the bone deteriorates and there is an increased risk of fractures. Calcium has also been found to assist in the production of lymphatic fluids.

Recommended Adequate Intake by the IOM for Calcium:^[3]

For more information about calcium in living nature, see calcium in biology and calcium metabolism.

Dietary calcium supplements

Calcium supplements are used to prevent and to treat calcium deficiencies. There are conflicting recommendations about when to take calcium supplements. However, most experts agree that no more than 500 mg should be taken at a time because the percent of calcium absorbed decreases as the amount of calcium in the supplement increases.^[3] It is recommended to spread doses throughout the day, with the last dose near bedtime. Recommended daily calcium intake varies from 1000 to 1500 mg, depending upon the stage of life.

In July 2006, a report citing research from Fred Hutchinson Cancer Research Center in Seattle, Washington claimed that women in their 50s gained 5 pounds less in a period of 10 years by taking more than 500 mg of calcium supplements than those who did not. However, the doctor in charge of the study, Dr. Alejandro J. Gonzalez also noted it would be stretching it to suggest calcium supplements as a weight-limiting aid.^[4]

A citrate is an ionic form of citric acid, such as C₃H₅O(COO)₃^3-, that is, citric acid minus three hydrogen ions.

Citrates are compounds containing this group, either ionic compounds, the salts, or analogous covalent compounds, esters. An example of a salt is sodium citrate and an ester is trimethyl citrate. See category for a bigger list.

Since citric acid is a multifunctional acid, intermediate ions exist, hydrogen citrate ion, HC₆H₅O₇^2- and dihydrogen citrate ion, H₂C₆H₅O₇^-. These may form salts as well, called acid salts.

Salts of the hydrogen citrate ions are weakly acidic, while salts of the citrate ion itself (with an inert cation such as sodium ion) are weakly basic.

Citrate is a key component in the commonly used SSC 20X hybridization buffer. There exists authoritative literature (Maniatis) that incorrectly instructs the preparation of this buffer to include 3M NaCl and 0.3M Sodium Citrate, to be titrated up with NaOH to a pH of 7. When the two components are actually mixed together, the pH is slightly basic. Therefore, the pH of the solution should instead be titrated down to 7 with HCl.

Malate (O^-OC-CH₂-CH(OH)-COO^-) is the ionized form of malic acid. It is an important chemical compound in biochemistry. In the C4 carbon fixation process, malate is a source of CO₂ in the Calvin cycle.

In the citric acid cycle, (S)-malate is an intermediate formed by the addition of an -OH group on the si face of fumarate; it can also be formed from pyruvate via anaplerotic reactions. Malate dehydrogenase catalyzes the reversible conversion of malate into oxaloacetate using NAD as a cofactor.

Malate is also produced from starch in guard cells of plant leaves. A build up of malate leads to a low water potential. Water then flows into the guard cells causing the stoma to open. However, this process does not always induce the opening of stomas.