Feeling fatigued constantly or having low energy levels may alert your doctor to draw blood to evaluate your ferritin levels. This routine test lets you know if your iron stores are low, a sign of anemia. Iron can be toxic at high doses so if you think you need to take an iron supplement, talk with your physician ahead to time to ensure you ingest the correct dosage for your particular situation.
Functions of Iron
You need iron to transport oxygen around in your blood. Most of the iron in your body attaches to hemoglobin, a protein that delivers oxygen to tissues and organs. Smaller amounts of iron cling to myoglobin and carry oxygen to muscles. Some iron is also involved in activating enzymes you need for an array of biochemical reactions.
Types of Iron
Iron can be heme or nonheme, depending on its source. Heme iron attaches to hemoglobin in blood and is found in meat, seafood, dairy and eggs. Nonheme iron absorbs into plants through soil and water. Vegetables, grains, fortified foods and dietary supplements all provide nonheme iron. Both types of iron are important in your diet, but heme iron is easier for your body to absorb.
Ferritin is a protein inside cells that stores iron for later use. If you have a low intake of iron or poor iron absorption, your ferritin levels may be low. Normally, women should have ferritin levels between 12 and 150 ng/ per mL, while men's levels should fall between 12 and 300 ng per mL, reports MedlinePlus. Low ferritin levels may be an indicator of iron-deficient anemia, letting you know you may need to add a supplement to your diet. Keep your iron stores up by ingesting the recommended dietary allowance, or RDA, for your gender. Healthy adult men require 8 mg iron daily, while women need 18 mg, says the Office of Dietary Supplements. Check with your doctor before starting an iron supplement to make sure you're getting the right kind and amount for you.
Some types of iron supplements are easier for your body to absorb than others. Iron supplements provide nonheme iron, which comes in ferrous or ferric forms. Your iron supplement lists the amount of elemental iron on the label. This is the amount of iron within the supplement that is available for your body to absorb. Ferrous iron is the best type of iron supplement, since it is easy for your body to absorb and has the highest amount of elemental iron. Ferrous fumarate is 33 percent elemental iron, but ferrous gluconate is only 12 percent elemental iron, explains the Linus Pauling Institute. If you take a multivitamin with iron or a separate iron supplement, ensure that your supplement provides one of the ferrous salts, such as fumarate or sulfate, both of which are excellent sources of ferrous iron.