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Mineral Guide

The American Dietetic Association provides the following information on minerals.

Our bodies need at least 15 minerals to function:



    Functions: Calcium builds bones, both in length and strength, and helps slow the rate of bone loss as you age. It helps muscles contract, plays a role in normal nerve function, and helps blood coagulate when bleeding.

    Deficiency problems: Affects bone density and increases the risk of osteoporosis.

    Food sources: Milk and milk products, some dark green leafy vegetables (kale, broccoli, bok choy), fish with edible bones and tofu made with calcium sulfate. Many foods are fortified with calcium, such as some brands of orange juice, bread and soy milk.

    Excess amounts: Too much calcium over a prolonged period can cause constipation, kidney stones and poor kidney function. It may also interfere with the absorption of other minerals, such as iron and zinc. Excess amounts are only consumed via supplements.

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    Functions: Phosphorus helps body cells produce energy and acts as a main regulator of energy metabolism in body organs. It is a major component of bones and teeth, and makes up part of DNA and RNA.

    Deficiency problems: Rare, except for small premature babies who consume only breast milk, or for people taking aluminum hydroxide- containing antacid for long periods. Symptoms include bone loss, weakness, loss of appetite and pain.

    Food sources: Protein-rich foods are the best sources. Legumes and nuts rank next. Bread and baked goods also contain phosphorus.

    Excess amounts: Too much phosphorus may lower calcium levels in the blood and increase bone loss if calcium intake is low.

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    Functions: Magnesium is an important part of more than 300 enzymes which regulate many body functions, including energy production and muscle contractions. It also helps maintain nerve and muscle cells and is a component of bones.

    Deficiency problems: When the body cannot properly absorb magnesium, irregular heart beat, nausea, weakness and mental derangement may occur.

    Food sources: Magnesium is found in all foods in varying amounts. Legumes, nuts, whole grains and green vegetables are good sources.

    Excess amounts: Too much magnesium can cause nausea, vomiting, low blood pressure and heart problems. Excess amounts from food are unlikely to cause harm unless kidney disease prevents magnesium from being excreted.

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    Functions: Chromium works with insulin to help the body use glucose (blood sugar).

    Deficiency problems: Symptoms may resemble diabetes, including impaired glucose tolerance and nerve damage.

    Food sources: Good sources include meat, whole grains and nuts.

    Excess amounts: The effects of too much chromium are being studied.

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    Functions: Copper helps make hemoglobin, which carries oxygen in the blood. It's also a part of many body enzymes and helps all body cells produce energy.

    Deficiency problems: Rare, except from genetic problems or consuming too much zinc, which can hinder copper absorption.

    Food sources: Organ meats, especially liver; seafood, nuts and seeds. Cooking in copper pots also increases copper content of foods.

    Excess amounts: Too much copper can cause nausea, vomiting, diarrhea, coma and liver damage.

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    Functions: Fluoride helps harden tooth enamel, protecting teeth from decay. It may also protect against osteoporosis by strengthening bones.

    Deficiency problems: Causes weak tooth enamel.

    Food sources: Tea (especially if made with fluoridated water) and fish with edible bones, such as canned salmon. Many communities add fluoride to the water supply, and fluoride supplements may be used with a doctor's supervision. Some types of cooking materials, such as Teflon, can increase the fluoride content of foods.

    Excess amounts: Too much fluoride can mottle or stain otherwise healthy teeth. It can also lead to brittle bones, increasing the frequency of bone fractures.

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    Functions: Iodine is part of thyroxin (thyroid hormone), which regulates the body's rate of energy use.

    Deficiency problems: Interferes with thyroxin production, slowing the rate at which the body burns energy. Symptoms include weight gain and goiter (enlarged thyroid gland). Use of iodized salt has virtually eliminated iodine deficiency as a cause of goiter in the United States.

    Food sources: Found naturally in saltwater fish and foods grown near coastal areas. Iodine is added to salt.

    Excess amounts: Too much iodine may also cause goiter, but not at levels usually consumed in the United States.

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    Functions: Iron is an essential part of hemoglobin, which carries oxygen to body cells.

    Deficiency problems: Anemia, fatigue and infections. Deficiencies are more common among women with regular menstrual periods.

    Food sources: Some iron from animal sources is better absorbed than plant sources. Sources include meat, poultry, seafood, legumes, nuts and seeds, breads, cereals and other grain products.

    Excess amounts: Adult iron supplements can be harmful to children; seek immediate medical attention if children accidentally take adult iron supplements. Iron supplements should not be taken by men, post menopausal women or people with a genetic problem called hemochromatosis.

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    Functions: Manganese is part of many body enzymes.

    Deficiency problems: Rare.

    Food sources: Whole grain products, tea and some fruits and vegetables such as pineapple, kale and strawberries.

    Excess amounts: Consuming harmful levels of manganese from food is very rare.

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    Functions: Molybdenum works with riboflavin to incorporate iron into hemoglobin for red blood cells. It is also part of many body enzymes.

    Deficiency problems: Rare with a normal diet.

    Food sources: Milk, legumes, breads and grain products.

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    Functions: Selenium works as an antioxidant with vitamin E to protect body cells from damage that may lead to cancer, heart disease and other health problems. It also aids cell growth.

    Deficiency problems: May affect the heart.

    Food sources: Seafood, liver, kidney and other meats. Grain products and seeds also contain selenium, but the amount depends on the type of soil in which they were grown.

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    Functions: Zinc is essential for growth. It promotes cell reproduction, tissue growth, repair and wound healing. It forms part of more than 70 body enzymes and helps the body use carbohydrate, protein and fat.

    Deficiency problems: Birth defects and retarded growth during childhood. Appetite loss, decreased sense of taste and smell, skin changes and reduced resistance to infection are also symptoms.

    Food sources: Meat, liver and seafood are the best sources. Whole-grain products, wheat bran, legumes and soybeans are good sources.

    Excess amounts: Excess zinc intake comes from supplements and can cause gastrointestinal irritation, vomiting, reduced HDL ("good") cholesterol levels and can interfere with copper absorption and immune function.

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    Functions: Chloride helps regulate fluids in and out of body cells. It forms part of stomach acid to help digest food and absorb nutrients. It also helps transmit nerve impulses.

    Deficiency problems: Rare, as chloride is found in table salt. Heavy, persistent sweating, chronic diarrhea or vomiting, trauma or kidney disease may cause deficiencies.

    Food sources: The best source is table salt.

    Excess amounts: Excess chloride may be linked to high blood pressure in chloride-sensitive people, but more study is needed.

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    Functions: Potassium helps regulate fluids and mineral balance in and out of body cells. It also helps maintain normal blood pressure, transmit nerve impulses and contract muscles.

    Deficiency problems: Prolonged vomiting, diarrhea, laxative use or kidney problems can result in deficiencies of potassium. Symptoms include weakness, appetite loss, nausea and fatigue. Supplements may be necessary for people taking high blood pressure medication -- check with your doctor.

    Food sources: Fruits, vegetables, fresh meat, poultry and fish. Particularly good sources include apricots, avocados, bananas, cantaloupe, grapefruit, honeydew, kiwi, oranges, prunes, strawberries, potatoes, tomatoes and dried fruits.

    Excess amounts:Excess potassium is usually excreted; if this doesn't happen, as in people with some types of kidney disease, heart problems can occur.

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    Functions: Sodium helps regulate movement of fluids in and out of body cells. It also helps transmit nerve impulses, regulate blood pressure and relax muscles.

    Deficiency problems: Unlikely, except with chronic diarrhea, vomiting or kidney problems. Symptoms include nausea, dizziness and muscle cramps.

    Food sources: Processed foods account for about 75 percent of the sodium we eat. Another 25 percent comes from table salt. Only a small amount occurs naturally in food.

    FYI: Healthy people excrete excess sodium, but some kidney diseases interfere with sodium excretion, leading to fluid retention and swelling. Sodium-sensitive people may experience high blood pressure eating a daily diet that contains high levels of sodium.

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