Iron : It's good for your blood

Iron is essential for making hemoglobin, the protein in red blood cells that carries oxygen to other cells. It's also an important component of myoglobin (a protein that helps supply oxygen to your muscles), collagen (a protein in bone, cartilage, and other connective tissue), and many enzymes. What's more, iron helps you maintain a healthy immune system.

During pregnancy, your iron requirements go up significantly. First of all, your blood volume expands until you have almost 50 percent more blood than usual, so you need more iron to make more hemoglobin. You also need extra iron for your growing baby and placenta. Most women start their pregnancies without sufficient stores of iron to meet their body's increased demands — especially in the second and third trimesters — and are unable to bring their levels up through diet alone.

How much iron do I need during pregnancy?

The recommended amount for pregnant women is 27 milligrams (mg) a day, substantially more than the 18 mg a day you needed before you conceived.

Should I take a supplement?

Most experts think it's a good idea. Although your body absorbs iron more efficiently during pregnancy, you most likely won't be able to get enough of the mineral from your diet alone, even if you're a healthy eater. The Centers for Disease Control recommends that all pregnant women take a daily supplement containing 30 mg. At your first prenatal appointment, your practitioner will probably recommend a prenatal vitamin that contains at least 30 mg of iron as well as other nutrients.

What are the best food sources of iron?

Unless you're a vegetarian, red meat is one of your best sources of iron while you're pregnant. (Liver provides the highest concentration of iron, but it also contains unsafe amounts of vitamin A and is best avoided during pregnancy.)

Meat, poultry, and fish provide a form of the mineral called heme iron that's easier for your body to absorb than the kind found in legumes, vegetables, and grains, which is called nonheme iron. (Nonheme iron is also the kind that's used in iron-fortified foods and supplements.) That's why it can be hard for vegetarians to get enough iron from their diet.

However, this doesn't mean you need to eat a big slab of meat every day to fill your iron requirement. Adding just a little meat or fish to a meal will help your body absorb more of the iron in the other foods on your plate. So will adding foods rich in vitamin C, such as orange juice, strawberries, or broccoli.

Here are a few more tips for getting as much iron as possible from the food you eat: Cook in a cast-iron pan. (Moist, acidic foods, such as tomato sauce, are especially good at soaking up iron this way.) Cut back on coffee and tea, or drink them between meals, because they contain compounds called phenols that interfere with iron absorption. Calcium does, too, so if you take calcium supplements or antacids that contain calcium, take them between meals.

Common sources of heme iron:

* 6 fried oysters: 4.5 mg
* 3 oz. lean beef chuck (about the size of a deck of cards): 3.2 mg
* 3 oz. lean beef tenderloin: 3.0 mg
* 3.5 oz. roast turkey, dark meat: 2.3 mg
* 3.5 oz. roast turkey, light meat: 1.6 mg
* 3.5 oz. roast chicken, dark meat: 1.3 mg
* 3 oz. roast chicken breast: 1.1 mg

Common sources of nonheme iron:

* 3/4 cup ready-to-eat cereal, 100 percent iron-fortified: 18 mg
* 1 cup instant fortified oatmeal: 10 mg
* 1 cup edamame (boiled soybeans): 8.8 mg
* 1 cup cooked lentils: 6.6 mg
* 1 cup cooked kidney beans: 5.2 mg
* 1 cup cooked black or pinto beans: 3.6 mg
* 1 tablespoon blackstrap molasses: 3.5 mg
* 1/2 cup raw, firm tofu: 3.4 mg
* 1/2 cup boiled spinach: 3.2 mg
* 1 cup prune juice: 3 mg
* 1/2 cup raisins: 1.5 mg

What will happen if I don't get enough iron?

When you're not getting enough iron, your stores become depleted over time. If you get to the point where you no longer have enough iron in your blood to make the hemoglobin you need, you become anemic. Iron-deficiency anemia can sap your energy (and cause a host of other symptoms) and make it harder for your body to fight infection. It may also affect your pregnancy. Having iron-deficiency anemia in the first and second trimesters has been linked to an increased risk of preterm birth and a low-birthweight baby. And if you're anemic later in pregnancy, you're more likely to need a transfusion and have other problems if you lose a lot of blood when you give birth.

Your baby does a good job of taking care of his iron needs while he's in your uterus. He'll get his share of what's available before you do. However, if you're severely deficient, it may compromise your baby's iron stores at birth, increasing his risk for anemia later in infancy.

How will I know if I have iron-deficiency anemia, and how is it treated?

You may not have any symptoms at all and be surprised to learn that you're anemic after a routine blood test. Or you may feel tired, weak, and dizzy. You may be paler than usual, particularly in your fingernails, the underside of your eyelids, and your lips, and you may have a rapid heartbeat, heart palpitations, shortness of breath, or trouble concentrating. Finally, some studies have found a link between severe iron-deficiency anemia and cravings for non-food substances such as ice or clay (a condition known as pica).

Iron deficiency is very common in the United States and around the world, and you're particularly at risk when you're pregnant. That's why your practitioner tests your blood for anemia at your first prenatal appointment. If your test indicates that you're anemic, you'll need to take even more iron, usually 60 to 120 mg a day. (As with all supplements, don't boost your dose unless your practitioner advises you to, and take only the amount she recommends.) To increase absorption, take your iron pills on an empty stomach. Wash them down with water or orange juice (the vitamin C helps with absorption) but not with milk (calcium hinders absorption).

Note that these doses refer to the amount of "elemental iron," or pure iron, in a supplement. Some labels list the amount of ferrous sulfate (a kind of iron salt) instead of or in addition to the amount of elemental iron. A supplement that contains 325 mg of ferrous sulfate will give you about 60 mg of elemental iron.

One more important thing to note: Be vigilant about keeping pills that contain iron in childproof containers and away from children. More kids die from iron overdose every year than from any other kind of accidental drug poisoning. In fact, a single adult dose can be toxic to a small child.

Are there any side effects from taking a lot of iron?
High levels of iron in supplements can upset your gastrointestinal tract. Most commonly, they lead to constipation, which is already a problem for many pregnant women. But you may also have nausea or, more rarely, diarrhea. If you think this is the case for you, talk to your practitioner about it. If you're not anemic, it may make sense for you to switch to a prenatal vitamin with a lower dose of iron. If you are anemic, you may be able to avoid stomach problems by starting with less iron and then gradually building up to the dose you need, or by taking the iron in divided doses throughout the day. Some women find they have less trouble with the side effects from iron supplements when they take a time-released formula, although the trade-off is that the iron is not absorbed as easily this way.

If you think your supplement is making you feel queasy, try taking it at bedtime. If constipation is what's plaguing you, try drinking prune juice. It can help you stay regular (and is a good source of iron itself). Finally, don't worry if your stools look darker when you start taking iron. That's a normal side effect.