Avoiding Nutritional Pitfalls in a Gluten-Free Diet: All About Iron

Science Class

In most people, the absorption of iron from food and supplements is well regulated by the body, which increases or decreases iron absorption depending on how much iron it needs. Some people, however, have a genetic condition called hemochromatosis, which causes iron to be absorbed regardless of the body's needs. These people may experience a buildup of iron (iron overload), which eventually can lead to tissue and organ damage. For more information on hemochromatosis, see the Centers for Disease Control and Prevention website at cdc.gov/ncbddd/hemochromatosis. The Dietary Reference Intake (DRI) for iron for all adults except menstruating women is 8 milligrams per day. For menstruating women between the ages of nineteen and fifty, the DRI is 18 milligrams. The upper limit (the maximum amount that should be consumed) for iron is 45 milligrams.

The Gluten-Free Diet and Iron

With the proper food choices, a gluten-free diet can provide enough iron. However, a person following a gluten-free diet may find it more difficult to consume enough iron than a person following a typical American diet. This may be especially true for premenopausal women between the ages of nineteen and fifty, who require more than twice the amount of iron as similarly aged men. In the United States, grain-based foods account for a third of an adult's daily intake of iron, largely because of enrichment; most wheat-based grain foods are enriched with iron, and most mainstream breakfast cereals are fortified with iron. However, as mentioned, most refined gluten-free grain foods are not enriched, so this source of iron is not readily available to people with celiac disease. While whole grains also are an important source of iron, many gluten-free foods are made using refined flour and starch, so they contain very little iron.

Iron-Deficiency Anemia

As explained earlier, anemia can be defined as a decrease in the amount of hemoglobin in the blood. To make hemoglobin, the body needs iron. If the body doesn't have enough iron available to make hemoglobin, because of either poor dietary intake or poor absorption, iron-deficiency anemia may occur. Tiredness, one of the main symptoms of iron-deficiency anemia, is associated with the tissues of the body not getting enough oxygen. This type of anemia is referred to as a microcytic hypochromic anemia. This means that there are small red blood cells containing lower than normal amounts of hemoglobin.

Adding Iron to Your Diet

To increase your intake of iron, consume a variety of gluten-free whole and enriched grains, as well as lean meat, poultry, fish, legumes, vegetables, and fruits.

Whole-Grain or Enriched Gluten-Free Grain Foods

In the following table, various grain foods made from corn and rice are grouped together to show that whole grains and enriched grains contain more iron than refined, unenriched grains. Notice that teff and amaranth are iron superstars!

Meat, Fish, and Beans

Beef, chicken, pork, fish, and eggs are sources of heme iron. Legumes, nuts, and seeds are sources of nonheme iron. According to Dietary Guidelines for Americans, 2005, if you require 2,000 calories each day, you should be eating five and a half 1-ounce equivalents from this food group each day. A 1-ounce equivalent would be either 1 ounce of cooked beef, pork, chicken, and fish; one egg; ¼ cup of cooked dried beans, peas, or lentils; ¼ cup of tofu; 1 tablespoon of peanut butter; or ½ ounce of nuts or seeds.

If you like clams and oysters, you are in luck. They are iron superstars!

Iron Content of Foods from the Meat and Beans Group

Food	Amount	Iron
Clams (cooked)	1 ounce	7.93 milligrams
Oysters (cooked)	1 ounce	3.40 milligrams
Soybeans (cooked)	¼ cup	2.21 milligrams
Sesame seeds, whole	½ ounce (1½ tablespoon)	2.09 milligrams
White beans (cooked)	¼ cup	1.66 milligrams
Lentils (cooked)	¼ cup	1.65 milligrams
Tahini (ground sesame seeds)	1 tablespoon	1.34 milligrams
Kidney beans (cooked)	¼ cup	1.30 milligrams
Beef tenderloin, prime (cooked	1 ounce	0.87 milligram
Scallops	1 ounce	0.85 milligram
Pine nuts	½ ounce (84 nuts)	0.78 milligram
Tofu (raw, firm)	1 ounce	0.75 milligram
Turkey, dark meat (with skin, cooked)	1 ounce	0.66 milligram
Almonds	½ ounce (11 nuts)	0.64 milligram
Split peas (cooked)	¼ cup	0.63 milligram
Egg (hard-boiled)	1 egg	0.59 milligram
Pumpkin seeds, whole	½ ounce (43 seeds)	0.47 milligram
Turkey breast (with skin, cooked)	1 ounce	0.45 milligram
Walnuts	½ ounce (7 halves)	0.41 milligram
Chicken drumstick (with skin, cooked)	1 ounce	0.38 milligram
Halibut	1 ounce	0.30 milligram
Peanut butter, chunky	1 tablespoon	0.30 milligram
Chicken breast (skin removed,cooked)	1 ounce	0.29 milligram
Salmon, wild	1 ounce	0.29 milligram
Pork chop (boneless, cooked)	1 ounce	0.22 milligram

Fruits and Vegetables

The fruits and vegetables in the following table are sources of nonheme iron.

Dark Chocolate

Yes, you read right. Each ounce of a dark-chocolate bar contains 0.60 milligram of iron. Look for bars with at least 60 percent cocoa content. Premium brands usually list the cocoa content on their label. Don't go overboard, though; this isn't license to gorge yourself on chocolate! Even dark chocolate is high in fat.

Increasing Your Absorption of Iron

Many factors affect the absorption of iron, both negatively and positively. Apply the following information to help you absorb as much iron as possible from the foods you eat:

• Heme iron (iron from animal foods) is better absorbed than nonheme iron (iron from plant foods, enriched foods, and supplements). This is opposite of the situation with folate, where food folate is less well absorbed than folic acid from supplements and enriched food.
• Antacids and calcium may decrease absorption of both heme and nonheme iron, because they lower the acidity of the stomach. For this reason, you may want to avoid taking antacids or calcium supplements with meals.
• Tea, coffee, and wine decrease absorption of nonheme iron. These drinks contain substances called tannins, which bind to iron and decrease its absorption.
• Vitamin C (or ascorbic acid) increases the absorption of nonheme iron. Vitamin C releases bound iron from substances such as tannins and changes it to a form that is more easily absorbed. For this reason, you should consider eating a source of vitamin C (containing at least 25 milligrams) with your meals.