Healthy Eating: Mighty Minerals
A balanced diet means getting all of the minerals, as well as the vitamins, that your body needs to maintain good health. The best way to guarantee optimal intake of minerals is to understand why these nutrients are important and to learn how to design and consume a nutritious, balanced diet based on your individual needs. What Are Minerals?
Minerals are different from vitamins in that they do not contain carbon. This makes them inorganic compounds. They cannot be destroyed as easily as vitamins can by heat or poor handling. Minerals are involved in a variety of functions in the body. They help to both regulate body processes and give your body structure. Just like vitamins, minerals are only needed in small amounts.
All minerals are absorbed into your intestines and then are transported and stored in your body in various ways. Some minerals pass directly into your bloodstream, which transports them to the cells; the excess passes out of the body through the urine. Other minerals, such as calcium, attach to proteins and become part of your body structure (in the case of calcium, the bones). Because these types of minerals are stored, large amounts taken for a long period of time can be harmful.
More than sixty minerals are found in the body. Of those, twenty-two are considered essential to good health. Minerals are divided into two categories: major and trace. As the names imply, major minerals are required in larger amounts than trace minerals.
Potassium
Potassium is an electrolyte that works closely with its counterparts, chloride and sodium. Over 95 percent of potassium is in the body's cells. Potassium helps regulate the flow of fluids and minerals in and out of the body's cells. It also helps maintain normal blood pressure, maintain heart and kidney function, and transmit nerve impulses and contraction of muscles. Potassium is very important in converting blood sugar into glycogen, the storage form of blood sugar in your muscles and liver. A potassium shortage in the muscles can produce great fatigue and muscle weakness.
A potassium deficiency is unlikely for most healthy people because this mineral is so widely available in foods. Deficiency could occur as a result of chronic diarrhea, vomiting, diabetic acidosis, kidney disease, or prolonged use of laxatives or diuretics. Symptoms of potassium deficiency include weakness, loss of appetite, nausea, and fatigue.
Most people can handle excess potassium because it is excreted in the urine. If the excess cannot be excreted—for instance, in the case of someone with kidney disease—it can cause heart problems. These people will most likely be advised by their doctors to limit foods containing potassium.
ALERT! If you need to limit your potassium content, be aware that salt substitutes contain potassium chloride instead of the sodium chloride that is in table salt.
There is no RDA or DRI for potassium, but the minimum amount suggested for adults is 2,000 milligrams per day. Some experts recommend a higher intake, around 3,500 milligrams per day, to help protect against high blood pressure.
Potassium is found in a wide range of foods, but especially in fruits and vegetables as well as fresh meat, poultry, and fish. It is important to have a proper balance of potassium and sodium in the diet. Studies have indicated a possible link between a diet high in sodium and low in potassium with an increased risk of cancer, heart disease, high blood pressure, and stroke. On the other hand, a diet high in potassium and low in sodium may help to protect or decrease the risk for these health problems.
Sodium
Sodium is also an electrolyte that works closely with potassium and chloride. In contrast to potassium, most of the body's sodium is found outside the cells in blood and other body fluids. There is a pump in the membrane of all cells that flushes sodium out of and brings potassium into the cell. If sodium is not pumped out properly, water accumulates in the cell, causing it to swell.
Sodium helps regulate the movement of body fluids in and out of cells. It also helps relax your muscles (including your heart muscle), transmit nerve impulses, and regulate blood pressure. Sodium can contribute to hypertension by raising blood pressure.
A sodium deficiency is unlikely except in cases of prolonged diarrhea, vomiting, fasting, starvation, or kidney problems. Symptoms can include nausea, dizziness, dehydration, muscle weakness, loss of appetite, and muscle cramps.
Healthy people excrete excess sodium. In the United States, the typical diet contains excessive amounts of sodium. Processed foods are one of the biggest contributors to our sodium intake. The rest comes from table salt and small amounts that occur naturally in foods. There is no RDA or DRI for sodium; however, the amount considered safe and adequate is 500 milligrams daily. Healthy American adults should reduce their sodium intake to no more than 2,400 milligrams per day. This is almost 1¼ teaspoons of sodium chloride or table salt each day.
Fact: The American Heart Association says that "reducing the amount of sodium you consume may help you reduce or avoid high blood pressure."
Chloride
Chloride is another electrolyte that works closely with potassium and sodium. Chloride also helps regulate body fluids in and out of body cells. Chloride joins sodium in surrounding the fluids outside the cells. This mineral is a component of stomach acid that helps with the digestion of food and the absorption of nutrients. Chloride also helps to transmit nerve impulses.
A deficiency of chloride is rare since salt, which is made of sodium chloride, is such a large part of the typical American diet. The deficiency symptoms of chloride are similar to those of sodium. As stated earlier, many salt substitutes also contain chloride in the form of potassium chloride.
Magnesium
Every cell in the body needs magnesium. Magnesium is a requirement for more than 300 body enzymes, body chemicals that regulate all kinds of body functions. This mineral helps maintain normal nerve and muscle function, keeps heart rhythm steady, and helps keep bones strong. Magnesium is involved in energy metabolism and protein production.
Magnesium deficiency is rare in the United States. When magnesium deficiency does occur, it is usually due to excessive loss of magnesium in urine, gastrointestinal system disorders that cause a loss of magnesium or limit magnesium absorption, or a chronically low intake of magnesium, Deficiency can also result from an increase in urine output (like that caused by diuretics), poorly controlled diabetes, and alcoholism. Symptoms can include irregular heartbeat, nausea, weakness, and mental confusion.
Too much magnesium is not harmful unless the mineral is not excreted property due to disorders such as kidney disease. Signs of excess magnesium include mental status changes, nausea, diarrhea, appetite loss, muscle weakness, difficulty breathing, extremely low blood pressure, and irregular heartbeat. The UL for magnesium is 350 mg per day for adults over eighteen. Magnesium can be found in a wide variety of foods. The best sources include legumes, nuts, avocados, wheat germ, and whole grains. Green vegetables can be good sources, too.
Phosphorus
Phosphorus is second only to calcium in terms of its abundance in the body. Phosphorus contributes to the structure of bones and teeth. It helps generate energy in every cell in the body and acts as the main regulator in converting dietary carbohydrate, protein, and fat to energy. Phosphorus is vital to growth, maintenance, and repair of all body tissue. This mineral is also a component of many proteins. It helps activate B vitamins and is a component of the storage form of energy in the body.
Fact: Soft drinks contain as much as 500 milligrams of phosphoric acid, which can contribute to excessive intake if consumed regularly.
A deficiency of phosphorus is very rare. However, absorption can be reduced by the long-term and excessive use of antacids containing aluminum hydroxide, increasing the risk of deficiency. Symptoms can include bone loss, weakness, loss of appetite, and pain.
Too much phosphorus can lower the level of calcium in the blood, which can really be a problem if calcium intake is already low in the diet. This can result in increased bone loss and an increased risk for osteoporosis, or brittle bone disease.
Phosphorus is found in almost all food groups. The best sources are protein-rich foods like milk, meat, poultry, fish, and eggs. Legumes and nuts are also good sources. Whole grains can also be good sources of phosphorus.
Phosphorus has a daily UL set at 4 grams for adults aged eighteen to seventy, 3 grams for adults over seventy, 3-5 grams for pregnant women, and 4 grams for breastfeeding women.
Calcium
Calcium is one of the most abundant minerals in the body. The average healthy adult male body contains about 2 to 3 pounds of calcium; the average healthy female body contains about 2 pounds. Of course this amount depends on body composition, the size of the body frame, bone density, and on how much bone has been lost through the aging process. About 99 percent of the body's calcium is in the bones. The remaining 1 percent is found in body fluids and other cells.
Calcium's primary function is to help build and maintain bones and teeth. In addition, calcium helps blood clot, helps your muscles contract and your heart beat, helps regulate blood pressure, plays a role in normal nerve function and nerve transmission, and helps regulate the secretion of hormones and digestive enzymes. Calcium works in conjunction with vitamin D, phosphorus, and fluoride to help promote strong and healthy bones. Vitamin D is necessary for the absorption of calcium in the body.
Fact: A constant supply of calcium is needed throughout life, especially during growth spurts in childhood, during pregnancy, and while breastfeeding. But these are not the only times calcium is needed. It is important to get adequate calcium throughout your life.
Low levels of calcium intake can lead to osteomalacia (softening of the bones) and an increased risk of osteoporosis. A deficiency in children can interfere with growth. Even a mild deficiency throughout a lifetime can lead to a loss of bone and bone density. A decreased intake of calcium can also contribute to muscle spasms and leg cramps, as well as high blood pressure.
Calcium has a UL set at 2,500 mg per day for adults and children. No UL is established for infants. When consuming supplements up to this amount, no adverse effects are likely. However, higher doses over an extended period of time may cause kidney stones and poor kidney function, as well as reduce the absorption of other minerals such as iron and zinc.
Essential: Label claims on food packages can tell you a lot about the vitamins and minerals they contain. The terms "high," "rich in," and "excellent source of" mean the food has 20 percent or more of the daily value. The terms "good source," "contains," or "provides" mean 10 to 19 percent of the daily value is provided. And the terms "more," "enriched," "fortified," or "added" mean the food provides 10 percent or more of the daily value.
Some of the best sources of calcium are foods in the dairy group, such as milk, cheese, and yogurt. In addition, some dark green leafy vegetables, such as broccoli, spinach, kale, and collards, are also good sources. Other good sources include fish with edible bones, such as sardines and salmon, as well as calcium-fortified soymilk, tofu made with calcium, shelled almonds, cooked dried beans, calcium-fortified cereals, and calcium-fortified orange juice.
Minerals that are needed in smaller amounts than the major minerals are referred to as trace minerals or trace elements. Even though our bodies require only a small amount of these minerals, they are still very important to proper health. Most trace minerals are needed in amounts of less than 20 mg per day.
Other trace minerals include arsenic, silicon, vanadium, nickel, and boron. Little is known about these trace elements and their role in human health. In fact, there are no RDAs, DRIs, or safe and adequate ranges set for these minerals, because not enough is known about what the body requires for proper health and functioning. A healthy, varied, and balanced diet is the best way to ensure you consume safe and adequate amounts of these other trace minerals.
Zinc
Almost every cell in the body contains zinc, and it is also part of over 70 different types of enzymes. Zinc is known as the second most abundant trace mineral in the body. It is essential for normal growth and development and is vital to a healthy immune system. Zinc assists the body in using the macronutrients (carbohydrates, proteins, and fats). In addition, zinc functions in the production of proteins, proper functioning of the hormone insulin, the maintenance of your genetic code, and normal taste.
Is it helpful to take over-the-counter zinc lozenges when you feel the symptoms of a cold coming on? Scientists have found that in test tubes, zinc can prevent cold viruses from reproducing themselves. But as for its ability to fight the disease in the human body, the jury is still out. Some studies have shown that if zinc lozenges are taken within twenty-four hours of coming down with cold symptoms, they may help shorten the length of the cold.
Adequate levels of zinc are vital to good health because zinc is involved in so many enzyme and body functions. A deficiency of zinc in childhood can cause retarded growth; deficiency during pregnancy can cause birth defects. Other deficiency symptoms include loss of appetite, skin changes, and reduced resistance to infection. Too much zinc, especially from supplements, can trigger harmful side effects that include impaired copper absorption. The UL for zinc is 40 mg per day for adults over eighteen years of age.
Good food sources of zinc include animal foods such as meat, seafood, and liver. Milk and eggs supply a little less zinc. Foods such as whole-grain products, wheat germ, legumes, nuts, and seeds have a good concentration of zinc; however, the zinc that plant foods provide is less available to the body.
Iodine
Iodine is a component of the thyroid hormone called thyroxin. Thyroxin regulates the rate at which the body burns calories or uses energy from food. With a deficiency of iodine, the body cannot make sufficient amounts of thyroxin. As a result, the rate at which the body burns calories slows down. A deficiency can be especially harmful in pregnant women, the developing fetus, and the newborn. Poor iodine intake is associated with hypothyroidism and/or the development of an enlarged thyroid gland, commonly called a goiter. Too much iodine can also cause the development of a goiter, but this is not common at the levels that are consumed on average in the United States. Iodine has a UL set at 1,100 mcg per day for adults over eighteen.
Iodine is found naturally in saltwater fish and seafood such as seaweeds. Most of the iodine in the United States is ingested through the form of iodized salt.
Selenium
Selenium works with vitamin E as an antioxidant. Together they help protect cells from damaging free radicals that may lead to health problems such as cancer and heart disease. Selenium is also important in cell growth.
A severe deficiency, although extremely rare, is associated with a severe heart disorder. The body requires only a small amount of selenium. Too much selenium over prolonged periods of time can produce signs of toxicity that can be harmful. Selenium has a UL set at 400 mcg per day for adults over eighteen. A normal healthy diet with a variety of foods generally provides the selenium required for normal body function. Food sources of selenium include seafood, liver, and kidney, as well as other meats. Many plant foods contain selenium, such as grain products and seeds, but the amount is directly related to the level of selenium in the soil that produces the food. Most fruits and vegetables don't contain much selenium.
Copper
Copper is found in all the tissues in the body, but is concentrated in the brain, heart, kidney, and liver. Copper is the third most abundant essential trace mineral, after iron and zinc. Copper helps the body make hemoglobin (needed to carry oxygen to red blood cells) and red blood cells by aiding in the absorption of iron in the body. Copper is part of many enzymes in the body and helps produce energy in cells. In addition, copper helps make hormones that regulate a variety of body functions, including heartbeat, blood pressure, and wound healing.
Fact: A copper deficiency can cause iron deficiency, since copper is required for proper iron absorption and utilization.
Copper deficiency rarely comes from the diet. Most deficiencies are due to a genetic problem or from too much zinc. Copper toxicity is rare. High daily intakes can cause nausea and vomiting. Copper has a UL set at 10,000 mcg per day for adults over eighteen.
Copper is found mostly in organ meats, especially liver, and in seafood, nuts, and seeds. It can also be found in poultry, legumes, and dark green leafy vegetables. Cooking in copper pots increases the copper content of foods.
Manganese
Manganese serves as part of many types of enzymes, including enzymes involved in blood sugar control, energy metabolism, and thyroid hormone function. Manganese is widely distributed in food, so deficiencies are very rare. Deficiencies could be associated with impaired fertility, growth retardation, birth defects, and general weakness. Consuming harmful levels of manganese is also rare. Too much, though, could inhibit the absorption of iron, copper, and zinc. Manganese has a UL set at 11 mg per day for adults over eighteen. Manganese is found mostly in whole-grain foods, along with some fruits and vegetables.
Fluoride
Fluoride helps to harden tooth enamel and protect your teeth from decay. When the diet is adequate in fluoride, bones are stronger and more resistant to degeneration and osteoporosis, or brittle bone disease. Fluoride works with calcium, phosphorus, magnesium, and vitamin D to form and maintain healthy bones and teeth. A deficiency of fluoride can lead to weakened tooth enamel and a higher incidence of dental caries. Too much fluoride can cause mottling, pining, dulling, and staining of the teeth. Fluoride has a UL set at 10 mg per day for adults over eighteen.
The primary means of obtaining fluoride is drinking and/or cooking with fluoridated water. Fluoride is not widely available in foods, but it can be found in tea, especially if made with fluoridated water, and fish with edible bones, such as canned salmon.
Chromium
Chromium works closely with insulin to help your body use blood sugar or glucose. Without chromium, the action of insulin is blocked and blood sugar levels elevate. Chromium is critical to proper maintenance of blood sugar.
ALERT! A very popular supplement in the weight-loss world is chromium picolinate, which many manufacturers claim will help to improve your body's lean-to-fat ratio. Chromium picolinate is simply a form of the mineral chromium. Taking megadoses of any supplement is not recommended. Talk to your doctor if you are considering taking chromium picolinate supplements.
The primary sign of a chromium deficiency is intolerance to glucose, which leads to high blood sugar and insulin levels. This can sometimes look like diabetes. Consuming too much from dietary sources is unlikely. There is no UL established for chromium at this time. Trivalent chromium, the form in most chromium supplements, is extremely safe. The best sources of chromium include meats, eggs, cheese, and whole-grain foods.
Molybdenum
Molybdenum works with riboflavin to help form the body's iron into hemoglobin for making red blood cells. Molybdenum functions as a component of many different enzymes. With a normal diet there is no worry of deficiency, because this mineral is needed in such small amounts. Too much molybdenum can interfere with the body's ability to use copper. Molybdenum has a UL set at 2,200 mcg per day for adults over eighteen. Molybdenum is found mostly in milk, legumes, bread, and grain products.
Iron
Iron is the mineral that occurs in the greatest amount in the blood. Almost two-thirds of the iron in your body is found in hemoglobin, the protein in red blood cells that carries oxygen to your body's tissues. Smaller amounts of iron are found in myoglobin, a protein that helps supply oxygen to muscle and contributes to the color of muscle. About 15 percent of your body's iron is stored for future needs, and activated when dietary intake is inadequate. The remainder is in your body's tissues as part of proteins that help your body function. Iron is also needed for a strong immune system and for energy production.
In the United States, iron deficiency is one of the most common nutrient deficiencies. Iron deficiency can lead to anemia, fatigue, and infections. Anemia, the last stage of iron deficiency, is a condition in which the blood is deficient in red blood cells or the hemoglobin (iron-containing) portion of red blood cells. Symptoms include extreme fatigue due to the lack of oxygen being delivered to needed tissues. Iron is the most common though not the sole cause of anemia.
Fact: If you feel you are a candidate for possible iron deficiency, or you feel you may have symptoms, talk with your doctor about testing your iron stores before self-prescribing a supplement.
Certain types of people are at higher risk for iron deficiency and should be screened periodically:
- Infants and children, because of their growth and choosy eating habits.
- Adolescents, especially girls who have started their menstrual cycle, who consume a junk food diet.
- Women who are pregnant, because they are supporting their needs as well as the baby's.
- The elderly population, because of poor dietary intake and decreased iron absorption due to aging.
- Women of childbearing age who experience excessive menstrual bleeding, because they are losing iron-rich blood each month.
- Strict vegetarians who eat only plant foods, because the iron in these foods is not absorbed as well as the iron in animal products.
- People who abuse crash diets and people suffering from eating disorders, because there is a good chance they are not meeting their requirements for iron.
- A person who loses an excessive amount of blood through surgery or other incident.
Fact: Women who are menopausal and postmenopausal have a decreased need for iron.
Your body usually maintains normal iron status by controlling the amount of iron absorbed from food, but iron can build up and become harmful in people who have a genetic disorder called hemochromatosis. This disorder, which usually occurs in men, causes excessive iron to accumulate in soft tissue. The result can be heart problems and other abnormalities. In children, large amounts of iron can have serious consequences. Keep iron supplements and other adult nutrient supplements out of the reach of children. Children should get immediate medical attention if they take an overdose of iron supplements.
Iron supplementation may be indicated when an iron deficiency is diagnosed and when diet alone cannot restore bodily iron content to normal levels within an acceptable time frame.
Taking iron supplements can cause side effects such as nausea, vomiting, constipation, diarrhea, dark colored stools, and/or abdominal distress. To minimize these side effects, take the supplement in divided doses and with food. It is best to seek the advice of your doctor before taking an iron supplement. Iron has a UL set at 45 mg per day for adults over eighteen.
Food Sources of Iron
| Good sources of heme iron | Good sources of nonheme iron |
| Beef liver | Fortified breakfast cereals |
| Lean red meats | Nuts and seeds |
| Poultry | Bran |
| Pork | Spinach |
| Salmon | Legumes |
| Lamb | Lentils |
| Veal | Dried fruit Egg yolk (exception to the rule) Whole-wheat bread Wheat germ Enriched rice, cooked |
Iron is contained in foods of both plant and animal origin. The iron in plant foods is called nonheme iron and is not absorbed as well as the iron from animal foods, called heme iron. Consuming vitamin C-rich foods at meals can help enhance your body's ability to absorb nonheme iron. This is especially important for strict vegetarians, who do not eat animal foods. Grain products, cereals, and flours that are enriched or fortified with iron are good dietary sources of nonheme iron. The improved iron status of millions of infants, children, and women has been attributed to the addition of iron to infant formula, cereals, and grain products.
Copyright © 2002 by Kimberly A. Tessmer. Excerpted from The Everything Nutrition Book: Boost Energy, Prevent Illness, and Live Longer with permission of its publisher, Adams Media Corporation.
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