Supplement (iron deficient anemia) or depletion (hemochromatosis)

What is function of iron in human body?

Iron is an essential metal for human physiology, and it is involved in several cellular metabolic reactions including oxygen transport. Most living organisms have developed different strategies to acquire, store, and recycle iron. In humans, inorganic iron is reduced in the gut lumen and absorbed by divalent metal cation transporters expressed by epithelial cells in the duodenum. A different source of iron is represented by heme-iron, which is directly absorbed, mainly in the large intestine, through specific receptors. Once absorbed, it is transported into the bloodstream, bound to transferrin, and stored in the liver.

What are the sources of iron?

The main dietary iron uptake is heme-iron, derived from meat and fish; while non-heme iron is derived from plants, vegetables (green leaves), algae, mushrooms, fruits, and iron-fortified foods. Some nutrients influence iron absorption: vitamins like ascorbic acid (vitamin C) enhance its absorption. Probiotics also enhances iron absorption. Cysteine present in meat and fish increases inorganic iron absorption rates from vegetables up to two- to three-fold its baseline. Polyphenols like phytate (beans, seeds, nuts, and grains) reduce its bioavailability and absorption. Also, calcium and zinc can inhibit iron absorption, even when it is administered as Ca salts or in dairy products.

Food high in phytic acid (phytates), inhibit absorption of following minerals:

  • Calcium
  • Magnesium
  • Iron
  • Zinc
  • Chromium
  • Manganese

However, recent studies have shown that phytic acid's anti-nutrient effect occurs only when large amounts of phytates are consumed within a diet that is already lacking nutrition. It also only affects the absorption of nutrients eaten at the same meal.