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Wednesday, April 13, 2005
Calcium, Phosphorus, Magnesium Minerals Do a Body Good
By Patricia Aaron
For the Journal
NEW MEXICO'S OWN: Today Patricia Aaron continues her exploration into the science link in the food chain with a look at: calcium, phosphorus and magnesium.
Minerals have two general functions in the body— building and regulating. Their building function affects the skeleton and all soft tissues. They regulate the heartbeat, blood clotting, the internal pressure of body fluids, nerve response and oxygen transportation from the lungs to the body tissues.
Some minerals are needed in the diet in relatively large amounts (more than 100mg daily). Calcium, phosphorus and magnesium, among others, are examples categorized as major minerals. If we require less than 100mg of a mineral daily, it's considered a trace mineral. Copper, zinc, selenium and iron are trace minerals.
Some minerals, such as lead, mercury and cadmium, are regarded as harmful.
Calcium is the most abundant mineral found in the body. Nearly 99 percent of the 2 to 3 pounds present in the body is concentrated in bones and teeth. The remaining 1 percent circulates within the bloodstream.
The bones act like a savings account for calcium from which the body makes a "withdrawal" when blood levels dip. The bones, however, pay the price. During childhood and teen years, "deposits" of new bone are added to the skeleton faster than old bone is removed. We reach peak bone mass (maximum bone density and strength) around age 30. After age 35 or so, bone "withdrawals" begin to exceed "deposits" from the savings account. This failure to maintain enough bone mass can eventually result in osteoporosis, a crippling bone disease.
Osteoporosis can lead to fractures in old age, as well as to loss of teeth. Despite stories of his wooden teeth, President George Washington must have had plenty of calcium in his diet, as he loved ice cream. History shows that he ordered thousands of gallons of ice cream over the years, and spent about $200 for ice cream during the summer of 1790 alone.
Today we recommend dairy sources of calcium, such as low-fat milk and milk products, as well as fish with bones, such as sardines and canned salmon, broccoli and calcium-fortified soy products and juices. Low-fat dairy products offer just as much, or even more, calcium than higher fat versions.
The Daily Value for calcium varies with age and gender: men 25-65 years (1,000mg); women 25-50 (1,000mg); men over 65, women who are pregnant, nursing or over 50 (1,500mg).
Younger people in general tend to absorb calcium better than older people, especially post menopausal women. Calcium absorption for post menopausal women is very poor; these women may absorb as little as 20 percent of dietary calcium because the hormone estrogen plays a key role in absorption.
Calcium absorption can be inhibited by insoluble fiber, oxalates in cocoa, spinach and soybeans, the mineral iron and too much coffee. Recent studies support dairy calcium's role in protecting against colon cancer. Dairy calcium may bind cancer-causing substances in the colon, or it may influence cells in the colon's lining. Dietary calcium also may help in our fight against obesity as it appears to play a role in the regulation of energy metabolism.
About 85 percent of phosphorus in the body is found in the bones and teeth. The rest circulates freely in the bloodstream and operates inside cells— phosphorus is an important part of every tissue. Phosphorous is widely distributed in foods, so a sufficient supply is easily obtained in the diet. Milk, cheese, bakery products and meat provide most of the phosphorus in our diets.
Cereals, bran, eggs, nuts and fish are also good sources. The adult Daily Value for phosphorus is 1,000mg.
Magnesium is found in all body tissue, but principally in the bones. Bone contains 60 percent of the body's magnesium. The rest circulates in the blood and operates inside cells. Excellent sources are whole grains, broccoli, squash, beans, nuts and seeds.
Dairy products, chocolate and meat also contribute magnesium. "Hard" tap water, such as we find in this area, often contains a high concentration of magnesium. The DV is 400mg. As calcium in the diet increases, magnesium absorption decreases.
Find some good sources of magnesium that you like and eat them regularly. To ensure that your diet has enough calcium, phosphorus and magnesium, drink low-fat milk, calcium-fortified fruit juice or milk-based cocoa, instead of soft drinks, with meals or as a snack.
Patricia Aaron is the extension home economist and a professor with the Bernalillo County Cooperative Extension Service and New Mexico State University.
RICE PUDDING
Adjusted for high altitude
Makes 6 1/2-cup servings
41/2 cups low-fat milk
1 cup brown rice
3 wide strips orange peel
2 tablespoons sugar
Pinch of salt
1 teaspoon vanilla extract
Pinch of nutmeg
1/2 cup dried cranberries
1/4 cup golden raisin
1/4 cup toasted chopped pecans
In a saucepan, bring milk, rice, orange peel, sugar and salt to a boil. Cover and gently simmer 11/4 hours or until rice is tender and milk is almost absorbed, stirring occasionally. Stir in vanilla and nutmeg and cook over low heat, stirring occasionally, 8 minutes or until pudding is thick. Remove orange peel. Stir in cranberries, raisins and pecans.
PER SERVING: 258 calories, 3g fat, 50g carbohydrates, 3g fiber, 137mg sodium.