Iron is a mineral vital for performing various functions in the human body. Its most important function is that it is one of the components of hemoglobin, the protein present in red blood cells that helps the blood to carry oxygen throughout the body. Therefore, it becomes essential to know about dietary iron, our main source of iron.
If the body does not have enough iron, it cannot make hemoglobin. This results in the development of iron deficiency anemia.
Anemia is defined as a decrease in the amount of red blood cells or hemoglobin in the blood which decreases the ability of the blood to carry oxygen.
A diet plan for anemia needs to include a healthful balance of iron-rich foods, such as leafy vegetables, lean meat, nuts and seeds, and fortified breakfast cereals. It is also crucial to include foods that can improve the body’s absorption of iron and avoid foods that may interfere with this process.
Dietary Iron Requirement
- 0 to 6 months: 0.27 mg
- 7 to 12 months: 11 mg
- 1 to 3 years: 7 mg
- 4 to 8 years: 10 mg
- 9 to 13 years: 8 mg
- 14 to 18 years: 11 mg
- 19 years and older: 8 mg
- 9 to 13 years: 8 mg
- 14 to 18 years: 15 mg
- 19 to 50 years: 18 mg
- 51 years and older: 8 mg
- During pregnancy: 27 mg
- Lactating females < 19 years : 10 mg
- Lactating females > 19 years: 9 mg
People with iron-deficiency anemia need a significant boost and require 150–200 mg of iron a day.
Forms of Iron Present in the Body
Iron is present in foods in two forms: heme iron and nonheme iron.
Heme iron is found in animal products like meat, poultry, and seafood.
Nonheme iron is found in plant foods and foods fortified with iron.
The human body can absorb both these types, but heme iron is absorbed more easily. The body absorbs two to three times more iron from animal sources than from plants.
Absorption of nonheme iron is greatly influenced by the presence of other substances in the diet.
Animal sources of dietary iron are
- Lean beef
Plant sources of dietary iron are
- Dark green leafy vegetables
- Beans and lentils
- Baked potatoes
- Fortified breakfast cereals
- Whole-grain and enriched bread
Green leafy vegetables, especially dark ones, are among the best sources of nonheme iron. They include
- Mustard greens
- Collard greens
- Dandelion greens
- Swiss chard
Some green leafy vegetables such as spinach and kale although having a high iron content, are also rich in oxalates. These compounds prevent the absorption of nonheme iron. So, while greens are useful in preventing and curing anemia, one can’t depend on them solely for iron deficiency anemia.
Vitamin C helps the body to absorb iron. Eating leafy greens with foods that contain vitamin C such as oranges, red peppers, and strawberries increase iron absorption. In addition, some green vegetables are good sources of both iron and vitamin C, such as collard greens and Swiss chard.
Cooking in iron utensils is a very important aspect that can increase the amount of iron present in the diet.
Dietary Substances Which Increase the Absorption of Nonheme Iron.
Meat, Fish, and Poultry
Consumption of heme iron along with nonheme iron enhances the absorption of nonheme iron.
Acidic Foods (Vitamin C, Citric acid, Lactic acid)
Citrus fruits such as orange, kiwi, lemon, Indian gooseberry (amla), guava, grapefruit, and vegetables such as broccoli, cauliflower, Brussel sprouts, and capsicums are rich, natural sources of vitamin C. Other vitamin C-rich fruits include papaya, cantaloupe, and strawberries.
Honey, dried figs, grapes, apples, and pears
Dietary Substances which Inhibit the Absorption of Nonheme Iron.
Phytates and Fibers
Phytates and fibers are found in foods such as whole grains, soy, nuts, and legumes, and can reduce the amount of nonheme iron that is absorbed by the body. Some foods rich in phytates, such as oatmeal, spinach, beets, etc are also good sources of nonheme iron. So it is better to have these along with food substances which enhance iron absorption.
Oxalates are common, naturally-occurring chemicals found in a number of food products such as fruits, vegetables such as spinach and kale, nuts and seeds, grains, and black tea. They reduce the absorption of iron by combining with iron to form a compound called iron oxide.
Calcium and Phosphorous
These also reduce the iron absorbed by the body. To prevent this effect, the time gap between the intake of calcium- and phosphorous-rich foods (e.g. milk, yogurt, or cheese) and nonheme foods should be increased.
Tannins and Polyphenols
These are naturally occurring compounds present in tea and coffee that inhibit iron absorption. These compounds bind with iron, thereby making nonheme iron unavailable for absorption.
Excess Intake of Other Minerals
Zinc, calcium, magnesium, and copper can inhibit nonheme iron absorption by competing for the same binding sites as iron. If a person is taking multivitamins and mineral supplements, there should be an adequate time gap between these and iron-rich food.
Eggs contain phosphoprotein, which binds with iron and impairs iron absorption. So egg and nonheme iron-rich food should not be eaten together.
Low Stomach Acid
The acid present in the stomach is required for the absorption of nonheme iron. So elderly individuals who produce less stomach acid coupled with the frequent use of antacids can greatly decrease the amount of iron absorbed in the stomach.
Thus, a diet plan for anemia needs to include a healthy balance of iron-rich foods, such as leafy vegetables, lean meat, nuts and seeds, and fortified breakfast cereals. It is also crucial to include foods that can improve the body’s absorption of iron and avoid foods that may interfere with this process.
Iron supplements (oral or injectibles) should be given when requirement can’t be fulfilled only through dietary intake especially a plant-based diet.
However to prevent iron deficiency anemia and to compensate for increased metabolic requirements, it is best to improve the diet since iron-rich foods also contain various other beneficial nutrients all of which are needed to maintain good health. In addition, intake of food substances which reduce or impair iron absorption should be curtailed while foods which enhance iron absorption should be consumed in more quantity.