Iron on the Periodic Table of the Human Body

Iron is the macromineral required by nearly all known organisms and is the chemical element on the periodic table with the symbol Fe (from Latin: ferrum), atomic number 26.

Ferrum has the longest and best described history among all the macronutrients. It is a key element in the metabolism of almost all living organisms.

In humans, ferrum mineral is an essential component of hundreds of proteins and enzymes.

Human body has only 3 to 5g of ferrum mineral, 75% of which is in hemoglobin, the pigment in red blood cells that carries oxygen from the lungs to the tissues and to export carbon dioxide back to the lungs. That oxygen is required for the production and survival of all cells in our bodies.

Another 25% is devoted to cellular proteins that use ferrum mineral for important cellular processes like storing oxygen in muscle cells, or performing energy-producing redox reactions.

As the body breaks down old red blood cells, it recycles most of the ferrum mineral. A healthy adult man loses 1 mg of it per day; compared to 1.5 mg per day in a woman who is still menstruating.

Ferrum is essential to life, because of its unique ability to serve as both an electron donor and acceptor. Its ability to donate and accept electrons means that if ferrum is free within the cell, it can catalyze the conversion of hydrogen peroxide into free radicals.

Free radicals can cause damage to a wide variety of cellular structures, and ultimately kill the cell. To prevent that kind of damage, all life forms that use ferrum, bind the ferrum atoms to proteins. That allows the cells to use the benefits of the mineral, but also limit its ability to do harm.

Human body uses finely tuned mechanisms to continuously regulate ferrum absorption and recycling.

The body has strict controls on the uptake of the mineral in the digestive tract and its subsequent distribution to organs. If something goes awry with the control mechanisms, however, the delicate balance is upset and ferrum builds up in the body, with harmful consequences.

Ferrum-related disorders can result from either too much or too little in the body. Balance is clearly all-important, but avoiding overload is a tricky task.


Ferrum mineral overload

When it accumulates in the liver there's no pathway for getting rid of iron. The results are cirrhosis, liver failure or liver cancer and in the heart reduce ability to pump blood causing irregular beat.

Excess of the ferrum mineral can also cause diabetes and problems in sexual development when it collects in the endocrine tissues.

A small amount is lost every day as a result of a natural process of skin and intestinal-lining cells, premenopausal in menstrual blood, but for the most part, the ferrum you take in—either through diet or blood transfusion—is what you have forever.

Mineral Ferrum deficiency

"Anemia" usually occurs when people don't get enough iron in their diets, when there is a blood loss or intestinal parasites deplete their ferrum stores. People most likely to develop an ferrum mineral deficiency are teenagers, menstruating woman, preschool children, some athletes and people on very restricted diets.

There are two types:

Heme iron from meat that is more easily broken down and absorbed and is found in red meat, pork, lamb, poultry, fish and eggs


Non-Heme iron in grains that is also found in animal products, as well as in vegetables, fruits, juices, grains and fortified cereals. The non-heme is less efficiently absorbed than that from animal sources.

The other minerals and chemicals in one type of food may inhibit absorption of ferrum from another type of food eaten at the same time. That is because non-heme from plant sources is less easily absorbed than the heme-bound ferrum of animal sources. Vegetarians and vegans should have a somewhat higher total daily ferrum intake than those who eat meat, fish or poultry.

Legumes and dark-green leafy vegetables like broccoli, kale and oriental greens are especially good sources of ferrum mineral for vegetarians and vegans.

However, spinach and Swiss chard contain oxalates which bind ferrum mineral making it largely unavailable for absorption. Ferrum from non-heme sources is more readily absorbed if consumed with foods that contain either heme-bound ferrum or vitamin C.

Dietary Sources of Iron (Based on usual serving size)


Excellent Source
(3.5 mg or more)
Good Source
(2.1 mg or more)
Source of
(0.7 mg or more)
  • N/A
  • beef, ground or steak cooked

  • blood pudding
  • chicken, ham, lamb, pork, veal

  • halibut, haddock, perch, salmon canned or fresh

  • shrimp, canned sardines, tuna

  • egg


    Excellent Source
    (3.5 mg or more)
    Good Source
    (2.1 mg or more)
    Source of
    (0.7 mg or more)
  • tofu

  • oysters, clams

  • cooked beans such as white beans, soybeans, lentils, chick peas

  • pumpkin, sesame, and squash seeds

  • breakfast cereals (enriched with iron)
  • canned lima

  • red kidney beans

  • chick and split peas

  • cooked enriched egg noodles

  • dried apricots
  • peanuts, pecans, walnuts, pistachios, roasted almonds, roasted cashews, sunflower seeds

  • cooked pasta, egg noodles

  • bread

  • pumpernickel bagel, bran muffin

  • cooked oatmeal

  • wheat germ

  • canned beets, drained

  • canned pumpkin

  • dried seedless raisins, peaches, prunes, apricots

  • Supplements

    Ferrum supplements are indicated for the prevention and treatment of ferrum mineral deficiency. Individuals who are not at risk of ferrum deficiency (e.g., adult men and postmenopausal women) should not take ferrum supplements without an appropriate medical evaluation for its deficiency.

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