Minerals

About minerals and Iron
Minerals are elements that originate in the Earth and cannot be made by living organisms. Plants obtain minerals from the soil, and most of the minerals in our diets come directly from plants or indirectly from animal sources. Minerals may also be present in the water we drink, but this varies with geographic locale. Minerals from plant sources may also vary from place to place, because soil mineral content varies geographically.
One of the mineral called Iron. Iron has the longest and best described history among all the micronutrients. It is a key element in the metabolism of almost all living organisms.
Function
Oxygen transport and storage
Heme is an iron-containing compound found in a number of biologically important molecules. Hemoglobin and myoglobin are heme-containing proteins that are involved in the transport and storage of oxygen. Hemoglobin is the primary protein found in red blood cells and represents about two thirds of the body's iron. Myoglobin functions in the transport and short-term storage of oxygen in muscle cells, helping to match the supply of oxygen to the demand of working muscles (3, 4).
Electron transport and energy metabolism
Cytochromes are heme-containing compounds that are critical to cellular energy production and therefore, life, through their roles in mitochondrial electron transport. They serve as electron carriers during the synthesis of ATP, the primary energy-storage compound in cells. Nonheme iron-containing enzymes, such as NADH dehydrogenase and succinate dehydrogenase, are also critical to energy metabolism (3).
Antioxidant and beneficial pro-oxidant functions
Catalase and peroxidases are heme-containing enzymes that protect cells against the accumulation of hydrogen peroxide, a potentially damaging reactive oxygen species (ROS), by catalyzing a reaction that converts hydrogen peroxide to to water and oxygen.
Oxygen sensing
Inadequate oxygen (hypoxia), such as that experienced by those who live at high altitudes or those with chronic lung disease, induces compensatory physiologic responses, including increased red blood cell formation, increased blood vessel growth (angiogenesis) and increased production of enzymes utilized in anaerobic metabolism.
DNA synthesis
Ribonucleotide reductase is an iron-dependent enzyme that is required for DNA synthesis (1, 2). Thus, iron is required for a number of vital functions, including growth, reproduction, healing, and immune function.
Regulation of intracellular iron
Iron response elements are short sequences of nucleotides found in the messenger RNA (mRNA) that codes for key proteins in the regulation of iron storage and metabolism. Iron regulatory proteins (IRP) can bind to iron response elements and affect mRNA translation, thereby regulating the synthesis of specific proteins.

Food Serving Iron content (mg)
Beef 3 ounces*, cooked 2.31
Chicken, dark meat 3 ounces, cooked 1.13
Oysters 6 medium 5.04
Shrimp 8 large, cooked 1.36
Tuna, light 3 ounces, canned 1.30
Black-strap molasses 1 tablespoon 3.50
Raisin bran cereal 1 cup, dry 5.00
Raisins, seedless 1 small box (1.5 ounces) 0.89
Prune juice 6 fluid ounces 2.27
Prunes, dried ~ 5 prunes (1.5 ounces) 1.06
Potato, with skin 1 medium potato, baked 2.75
Kidney beans 1/2 cup, cooked 2.60
Lentils 1/2 cup, cooked 3.30
Tofu, firm 1/4 block (~1/2 cup) 6.22
Cashew nuts 1 ounce 1.70