Prepared by
Diane Ball Linder, EdD, LDN, RD

Some people who are iron-deficient crave eating ice, clay or other unusual substances.

Iron-deficiency results from eating not enough iron-rich foods, blood loss or blood loss due to parasite infections of the gastro-intestinal tract.

Table of Contents for Minerals Introduction What You Will Learn Food Guide Pyramid What Are Minerals? Sodium Calcium Iron Web Site Activity Summary Review questions Back to Nutrition Curriculum Lessons

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Calcium

Calcium is required on the nutrition label. Calcium has many important uses in the body. This important mineral is used to build bones and teeth. Calcium helps keep your bones strong by slowing the rate of bone loss that can occur as you become older. If you get cut, calcium helps blood to clot. The clotting of blood helps you stop bleeding. Calcium is important for your heart to maintain a regular heartbeat. It's also necessary for muscles to contract as well as helps maintain healthy cell membranes. You see, calcium does so much for us, yet many of us don't get the amount of calcium that we need.

Calcium is found in three classes of food - milk and milk products, green vegetables and a few fish and shellfish. Calcium absorption is enhanced by vitamin D, phosphorus and lactose in milk. More calcium is lost in the urine by eating more protein than we need. When we increase our fiber intake, we need to increase the calcium we get from food since fiber decreases the absorption of calcium. We need the fiber, though.

Tools were developed by our government that help us see if we get the amount of calcium we need. One is the USDA Food Guide Pyramid and the other is the nutrition label on food labels. If we get the recommended number of servings of each of the basic five food groups in the USDA Food Guide Pyramid, we will get the calcium we need. On the nutrition label, the daily reference value for calcium is one gram. The lesson on milk provides more information on calcium.

Iron

Iron is necessary for the making of new cells, amino acids, hormones and for nerve cells to function. Most of the iron in the body is a part of hemoglobin or red blood cells. About 80 % of the iron in the body is found in the blood. Hemoglobin carries oxygen in the red blood cells. Smaller amounts of iron are found in myoglobin that is in muscle cells. The red blood cells act as a shuttle service, traveling back and forth between the lungs and the muscles and other parts of the body to carry and maintain a fresh supply of oxygen. Iron aids in use of energy and prevents iron deficiency anemia. Iron increases resistance to infection.

Since most of the iron in the body is found in blood, whenever you lose blood, you lose iron. Be sure to eat iron-rich foods and eat other foods with them to help increase the absorption of iron. If iron stores in the body are low and used up, the body cannot make enough hemoglobin to fill its new red blood cells that are being made. Without enough hemoglobin, the red blood cells are small and are lighter red than normal. Since hemoglobin is the bright red pigment of the blood, the skin of a fair person who is anemic may become pale. These smaller hemoglobin cells can't carry enough oxygen from the lungs to the tissues, so energy released in the muscle cells is impaired or doesn't function as it should. This affects every cell in your body. You could then feel tired, weak, have headaches and be apathetic. You also could have lowered resistance to colds and infections. Your body isn't able to regulate your body temperature as well. You may feel cold. Children with low intakes of iron become irritable and restless. Some people who are iron-deficient crave eating ice, clay or other unusual substances.

Iron-deficiency results from eating not enough iron-rich foods, blood loss or blood loss due to parasite infections of the gastro-intestinal tract.

In looking at the Food Guide Pyramid, the meat group is the best source of iron. Meat, fish, poultry and legumes are good sources. Vegetables, especially dark greens, are good sources of iron. Foods in the milk group are as poor iron sources as they are great calcium sources. Grain foods are good sources of iron. Iron is one of the enrichment nutrients. Select whole-grain or enriched breads and cereals. The more of them you eat, the more iron you receive. About 25 % of all the iron consumed in the United States comes from foods to which iron has been added, including enriched breads and cereals and fortified breakfast cereals. Although a single serving contributes very little iron, these food sources become significant sources of iron because people eat so much of them.

Iron occurs in two forms in foods: as heme iron, which is the type found in iron-carrying proteins hemoglobin and myoglobin in meats, poultry and fish. The other form of iron is called nonheme iron. Normally, about 10 % of the iron in food is actually absorbed by our body.

Heme iron provides about one to two milligrams of the 10 to 20 milligrams of iron the average person consumes in a day. Most of the dietary iron is nonheme iron. About one-fourth of the iron in heme iron is absorbed, but nonheme iron's absorption is affected by many factors. By thinking about these factors and planning accordingly, you can double or triple the amount of iron your body actually gets from foods. Small amounts of meat, fish, poultry or vitamin C help you better absorb the iron from other foods. To absorb the most iron, use one or both of these enhancing factors at every meal. The more vitamin C-rich foods, the better. Tea inhibits iron absorption. Coffee inhibits it a little less, and orange juice greatly enhances it.

Iron is one of the three minerals required to be on nutrition labels. Calcium and sodium are the other minerals. The nutrients listed on the nutrition labels reflect a focus on nutrients of public health concern that may help reduce the risk for certain diseases, instead of those that prevent vitamin and mineral deficiencies. The % Daily Value shows how the amount of iron in a serving of that particular food compares to 18 milligrams, the Daily Value for iron for the nutrition panel on the label.