Iron is an essential micronutrient in our diet. It's part of hemoglobin in blood and serves the purpose of transporting oxygen to cells. It’s also an essential part of many proteins and enzymes that maintain good health and is also essential for regulation of cell growth and differentiation. A deficiency of iron limits the delivery of oxygen to the cells resulting in fatigue, low work efficiency and poor immunity. On the other hand excess amounts can lead to toxicity and in extreme cases, even death.
Dietary iron is present in two forms, heme and nonheme. As the name suggests heme iron is present in the form of hemoglobin and is more bio-available than the nonheme form. Animal sources of Iron like red meat, fish and poultry are rich in heme form of iron (sorry vegetarians, meat wins here again) while the vegetarian sources contain the nonheme form. The following table shows the common sources of dietary iron separated by heme and nonheme sources. Please note that even though the plant based sources of iron seem richer in absolute quantities, they are poorly absorbed in the body. Also most fortified cereal and juices in the market contain the nonheme type of iron.
Absorption of iron in the body depends on the available reserves of iron. If the body is running low on iron reserves the absorption is high and when the reserves are high the absorption is low to protect against toxic effects of excess iron. Also animal sources of iron are absorbed anywhere from 15-35% while the absorption from plant sources is in the 2-20% range. Also iron from animal sources is absorbed independent of other dietary components while absorption of iron from plant sources is dependent on other components in diet. For example tannins (found in tea), calcium, polyphenols, and phytates (found in legumes and whole grains) can decrease absorption of nonheme iron. Some proteins found in soybeans also inhibit nonheme iron absorption. Keeping an adequate level of iron in the body is important for vitality and overall health. So if you are feeling fatigued and out of breath doing daily chores and keep getting sick often then perhaps fortifying your daily iron intake is in order.
