Calcium - The "Supernutrient"
Calcium - The "Supernutrient"
Calcium is the first nutrient approved by the FDA for the prevention of a specific disease. The “supernutrient” status of calcium stems from its potential to reduce the risk of osteoporosis, hypertension, colon cancer and other diseases.
Calcium is essential to life. Not only is it the principal mineral in bones and teeth, but calcium is also involved in blood clotting and muscle contraction, among other functions. All of these processes require maintenance of a constant level of blood calcium. Bone is the body’s calcium reserve. When dietary calcium intake is low, skeletal reserves of calcium are drawn upon. Any depletion of bone calcium results in a corresponding reduction in bone’s mechanical strength and eventually increased fracture risk.
High Blood Pressure (hypertension)
Since the mid-1980s, there has been accumulating evidence that a dietary pattern low in fat and rich in low-fat dairy foods, fruits and vegetables reduces blood pressure. A blood pressure reduction occurs often within two weeks that is comparable to that achieved with drugs. In addition, the blood pressure-lowering effect of a low-fat diet is often independent of sodium intake and changes in body weight. Researchers estimate that if the general population were to adopt such a diet, the decrease in blood pressure alone would reduce stroke by 27% and coronary heart disease by 15%.
Osteoporosis
It is important to understand that bone is not a hard and lifeless structure; it is, in fact, complex, living tissue. Our bones provide structural support for muscles, protect vital organs and store the calcium essential for bone density and strength. Because bones are constantly changing, they can heal and may be affected by diet and exercise. Until the age of about 30, you build and store bone efficiently. Then, as part of the natural aging process, your bones begin to break down faster than new bone can be formed. In women, bone loss accelerates after menopause, when your ovaries stop producing estrogen - the hormone that protects against bone loss. Think of your bones as a savings account. There is only as much bone mass in your account as you deposit. The critical years for building bone mass are from prior to adolescence to about age 30. Some experts believe that young women can increase their bone mass by as much as 20 percent - a critical factor in protecting against osteoporosis. A balanced diet rich in calcium and vitamin D, combined with weight-bearing exercise is highly recommended.
Colon Cancer
A protective role for calcium against colon cancer is demonstrated in several different types of scientific studies. Extensive data indicate that calcium reduces abnormal cell proliferation in the colon. A recent investigation of over 800 adults at risk for colon cancer because of removal of adenomatous polyps (i.e., precursors of colon cancer) from the colon found that adding 1200mg calcium per day to their diet reduced colon polyp adenomas by 19 to 24%.When patients at risk of colon cancer consumed an additional 800mg calcium per day from lowfat dairy foods (i.e., a total dietary intake of 1500mg calcium per day), several early markers of colon cancer were reduced. This beneficial effect was greater than expected from the level of calcium provided. The researchers speculated that other components in dairy foods may work together with calcium to produce these positive effects.
A protective role for calcium against colon cancer is demonstrated in several different types of scientific studies. Extensive data indicate that calcium reduces abnormal cell proliferation in the colon. A recent investigation of over 800 adults at risk for colon cancer because of removal of adenomatous polyps (i.e., precursors of colon cancer) from the colon found that adding 1200mg calcium per day to their diet reduced colon polyp adenomas by 19 to 24%.When patients at risk of colon cancer consumed an additional 800mg calcium per day from lowfat dairy foods (i.e., a total dietary intake of 1500mg calcium per day), several early markers of colon cancer were reduced. This beneficial effect was greater than expected from the level of calcium provided. The researchers speculated that other components in dairy foods may work together with calcium to produce these positive effects.
A protective role for calcium against colon cancer is demonstrated in several different types of scientific studies. Extensive data indicate that calcium reduces abnormal cell proliferation in the colon. A recent investigation of over 800 adults at risk for colon cancer because of removal of adenomatous polyps (i.e., precursors of colon cancer) from the colon found that adding 1200mg calcium per day to their diet reduced colon polyp adenomas by 19 to 24%.When patients at risk of colon cancer consumed an additional 800mg calcium per day from lowfat dairy foods (i.e., a total dietary intake of 1500mg calcium per day), several early markers of colon cancer were reduced. This beneficial effect was greater than expected from the level of calcium provided. The researchers speculated that other components in dairy foods may work together with calcium to produce these positive effects.
Dietary Calcium Calcium-rich foods include foods from the Milk Group (e.g., milk, yogurt, cheese). Green leafy vegetables, calcium-set tofu, shellfish, crustaceans and a few nuts are other calcium-containing foods. Food sources of calcium are usually good sources of other essential nutrients. This is why diets low in calcium are generally low in several other essential nutrients. For individuals who cannot meet all of their calcium needs from foods naturally containing this nutrient, fortified foods (e.g., breakfast cereals, bread, pasta) calcium supplements are advisable.
Supplement - Calcium Carbonate - There are several different forms of calcium available. Each form has a different degree of solubility and absorption. Older people often have a stomach acid deficit or take drugs such as Prilosec that block stomach acid production. Individuals with insufficient stomach acid output have been shown to absorb only about 4% of calcium carbonate supplements. Even people with normal levels of stomach acid only absorb about 22% of calcium carbonate supplements. Most commercial calcium preparations (including “oyster shell” calcium) and OTC anti-acid products contain lower-cost calcium carbonate.
Supplement - Calcium Citrate Malate - A form of calcium called calcium citrate is more effective at getting into the bloodstream. While people with insufficient stomach acid output absorb only about 4% of calcium carbonate supplements, they can absorb up to 45% of calcium citrate supplements. While calcium citrate is superior to most commercial calcium supplements, there is another form of calcium that has even better solubility and absorption. When the chelating agent malic acid is added to calcium citrate, calcium citrate malate is created, a compound that is 10 times more soluble than calcium citrate.
Recommendations
- The government has established new goals for the daily intake of calcium for men and women. Called AI (Adequate Intake), the figures below supplant the old RDA (Recommended Daily Allowance) and represent the amount of daily calcium that all individuals in the following age groups should try to meet: For men and women ages 50 to 70: 1,200 mg a day. For men and women ages 19 to 50: 1,000 mg a day.
- Your body can’t absorb more than about 500 mg of calcium at a time, so divide a daily dose of 1,000 mg, for example, into two doses of 500 mg and take them at different times of the day.
- In addition, when calculating your dose, make sure to look at the amount of “pure” or “elemental” calcium, not just the weight of each pill. The packaging will usually provide this information. For example, a 600 mg calcium carbonate tablet contains 240 mg of elemental calcium.
- The absorption of zinc, iron, and magnesium may be hindered by calcium, particularly when calcium is taken in high doses. Take a multimineral supplement to ensure balanced absorption of these other nutrients.
- Calcium carbonate may cause gas and constipation in some cases. If this happens, switch to calcium citrate. This should resolve the problem.
- Take calcium with food–it’s best absorbed that way. Orange juice and other foods with calcium citrate mixed right in can now easily be found on grocery store shelves.
- Avoid calcium supplements made from bone meal, oyster shells, or dolomite; they may contain high levels of lead.
- People over age 65 are advised to use calcium citrate because they may not have enough stomach acid to absorb calcium carbonate.
- Don’t consume calcium within one to three hours of taking an antibiotic such as doxycycline, minocycline, or tetracycline. It may decrease the absorption of the drug.
- If you use thiazide diuretics, consult your doctor before taking calcium supplements. When taken together, they can cause dangerously high calcium levels in the body, possibly resulting in kidney failure.
Sources:
- University of Oregon Health Sciences
- Columbia University College of Physicians & Surgeons