What is iron and why do we need it?

Iron is a mineral needed by our bodies. Iron is a part of all cells and does many things in our bodies. For example, iron (as part of the protein hemoglobin) carries oxygen from our lungs throughout our bodies. Having too little hemoglobin is called anemia. Iron also helps our muscles store and use oxygen.

Iron is a part of many enzymes and is used in many cell functions. Enzymes help our bodies digest foods and also help with many other important reactions that occur within our bodies. When our bodies don't have enough iron, many parts of our bodies are affected.

What is iron deficiency and why is it a concern?

Iron deficiency is a condition resulting from too little iron in the body. Iron deficiency is the most common nutritional deficiency and the leading cause of anemia in the United States.

The terms anemia, iron deficiency, and iron deficiency anemia often are used interchangeably but equivalent. Iron deficiency ranges from depleted iron stores without functional or health impairment to iron deficiency with anemia, which affects the functioning of several organ systems.

Iron deficiency is a concern because:

• Iron deficiency delays normal infant motor function (normal activity and movement) or mental function (normal thinking and processing skills).
• Iron deficiency anemia during pregnancy can increase risk for small or early (preterm) babies. Small or early babies are more likely to have health problems or die in the first year of life than infants who are born full term and are not small.
• Iron deficiency can cause fatigue that impairs the ability to do physical work in adults. Iron deficiency may also affect memory or other mental function in teens.

What is iron deficiency anemia?

Iron deficiency anemia is a condition that develops when a low iron level persists and prevents the body from making enough healthy red blood cells. The body can make red blood cells, even when it has an iron deficiency, but eventually the shortage of stored iron can slow that process and cause anemia.

Iron deficiency anemia often leads to symptoms of fatigue, which may lead sufferers to seek medical attention. When iron deficiency anemia is diagnosed it is almost always treated, since untreated anemia can cause damage to the heart and other organs.

What causes iron deficiency?

Iron deficiency has many causes. These causes fall into two main categories:

1. Increased iron needs

   Many common conditions can cause people to need additional iron:

   • Because of their rapid growth, infants and toddlers need more iron than older children. Sometimes it can be hard for them to get enough iron from their normal diet.
   • Women who are pregnant have higher iron needs. To get enough, most women must take an iron supplement as recommended by their health care provider.
   • When people lose blood, they also lose iron. They need extra iron to replace what they have lost. Increased blood loss can occur with heavy menstrual periods, frequent blood donation, as well as with some stomach and intestinal conditions (food sensitivity, hookworms).
2. Decreased iron intake or absorption (not enough iron taken into the body)

   The amount of iron absorbed from the diet depends on many factors:

   • Iron from meat, poultry, and fish (i.e., heme iron) is absorbed two to three times more efficiently than iron from plants (i.e., non-heme iron).
   • The amount of iron absorbed from plant foods (non-heme iron) depends on the other types of foods eaten at the same meal.
   • Foods containing heme iron (meat, poultry, and fish) enhance iron absorption from foods that contain non-heme iron (e.g., fortified cereals, some beans, and spinach).
   • Foods containing vitamin C (see Dietary Sources of vitamin C) also enhance non-heme iron absorption when eaten at the same meal.
   • Substances (such as polyphenols, phytates, or calcium) that are part of some foods or drinks such as tea, coffee, whole grains, legumes and milk or dairy products can decrease the amount of non-heme iron absorbed at a meal. Calcium can also decrease the amount of heme-iron absorbed at a meal. However, for healthy individuals who consume a varied diet that conforms to the Dietary Guidelines for Americans, the amount of iron inhibition from these substances is usually not of concern.
   • Vegetarian diets are low in heme iron, but careful meal planning can help increase the amount of iron absorbed.
   • Some other factors (such as taking antacids beyond the recommended dose or medicine used to treat peptic ulcer disease and acid reflux) can reduce the amount of acid in the stomach and the iron absorbed and cause iron deficiency.

The main causes of iron deficiency in children by age group include:

• Babies less than six months old - newborns receive their iron stores in the uterus (womb), which means the mother's diet during pregnancy is very important. Low birth weight or premature babies are at increased risk of iron deficiency and will need iron supplements. See your doctor for advice.
• Babies aged six months to one year - baby's iron stores run low in the second half of their first year. Iron deficiency can result if their diet doesn't include enough iron-rich solid food. At age four to six months, two servings per day of plain, iron-fortified infant cereal should be given. By approximately six months of age, plain pureed meats can be offered. Late introduction of solids into the baby's diet is a common cause of iron deficiency in this age group.
• Children aged one to five years - breast milk contains iron but prolonged breast-feeding can lead to iron deficiency if breast milk replaces solid foods in the diet. Low iron milks such as cow's milk, goat's milk and soymilk should not be given until 12 months of age. Children who drink milk in preference to eating solid foods are in danger of iron deficiency.
• Teenagers - adolescent girls are at risk because of a number of factors including growth spurts at puberty, iron loss through periods (menstruation), and risk of under-nutrition due to fad dieting that restricts the eating of a healthy range of foods.
• In general - gastrointestinal disorders, such as celiac disease, are a rare but possible cause of anemia in children.

Who is most at risk?

• Young children and pregnant women are at higher risk of iron deficiency because of rapid growth and higher iron needs.
• Adolescent girls and women of childbearing age are at risk due to menstruation.
• Among children, iron deficiency is seen most often between six months and three years of age due to rapid growth and inadequate intake of dietary iron. Infants and children at highest risk are the following groups:
  • Babies who were born early (premature) or small (low birth weight).
  • Babies given cow's milk before age 12 months.
  • Breast-fed babies who after age 6 months are not being given plain, iron-fortified cereals or another good source of iron from other foods.
  • Formula-fed babies who do not get iron-fortified formulas.
  • Children aged 1-5 years who get more than 24 ounces of cow, goat, or soymilk per day. Excess milk intake can decrease your child's desire for food items with greater iron content, such as meat or iron fortified cereal.
  • Children who have special health needs, for example, children with chronic infections or restricted diets.

Signs and symptoms of iron deficiency

Too little iron can impair body functions, but most physical signs and symptoms do not show up unless iron deficiency anemia occurs. Someone with early stages of iron deficiency may have no signs or symptoms. This is why it is important to screen for too little iron among high risk groups.

Signs and Symptoms of iron deficiency anemia include:

• Behavioral problems
• Loss of appetite
• Lethargy
• Breathlessness
• Increased sweating
• Strange 'food' cravings (pica) like eating dirt
• Failure to grow at the expected rate
• Feeling tired and weak
• Decreased work and school performance
• Slow cognitive and social development during childhood
• Difficulty maintaining body temperature
• Decreased immune function, which increases susceptibility to infection - repeat infections
• Glossitis (an inflamed tongue)

How is iron deficiency detected?

Your doctor or health care provider will do blood tests to screen for iron deficiency. No single test is used to diagnose iron deficiency. The most common tests for screening are:

• Hemoglobin test (a test that measures hemoglobin which is a protein in the blood that carries oxygen)
• Hematocrit test (the percentage of red blood cells in your blood by volume)

These tests show how much iron is in your body. Hemoglobin and hematocrit levels usually aren't decreased until the later stages of iron deficiency, i.e., anemia.

Sometimes other blood tests are used to confirm that anemia is due to iron deficiency. These might include:

• Complete blood count (to look at the number and volume of the red blood cells)
• Serum ferritin (a measure of a stored form of iron)
• Serum iron (a measure of the iron in your blood)
• Transferrin saturation (a measure of the transported form of iron)
• Transferrin receptor (a measure of increased red blood cell production)

How is iron deficiency treated?

• If you are found to have an iron deficiency, it is important to see your health care provider for treatment. Your treatment will depend on factors such as your age, health, and cause of iron deficiency.
• If your doctor or health care provider thinks that you have iron deficiency she or he may prescribe iron supplements for you to take and then ask that you return after a period to have your hemoglobin or hematocrit tested.
• If your health care provider determines that the iron deficiency is due to a diet low in iron, you might be told to eat more iron-rich foods. Your health care provider may also prescribe an iron supplement for you.

Again, it is important to be diagnosed by your health care provider because iron deficiency can have causes that aren't related to your diet. Your health care provider's recommendations will be specific to your needs.

What can I do to prevent iron deficiency?

In general, you can eat a healthful diet that includes good sources of iron. A healthful diet includes fruits, vegetables, whole grains, fat free or nonfat milk and milk products, lean meats, fish, dry beans, eggs, nuts, and is low in saturated fat, trans fats, cholesterol, salt, and added sugars.

In addition to a healthful diet that includes good sources of iron, you can also eat foods that help your body absorb iron better. For example, you can eat a fruit or vegetable that is a good source of vitamin C (see table on Dietary Sources of Vitamin C) with a food or meal that contains non-heme iron (see table on Dietary Sources of Iron). Vitamin C helps your body absorb the non-heme iron foods you eat, especially when the food containing non-heme iron and the vitamin-C rich food are eaten at the same meal.

The following recommendations are for specific groups who are at greater risk for iron deficiency.

Babies

• If possible, breast-feed your baby for at least 12 months and starting at 4 to 6 months of age, give your baby plain, iron-fortified infant cereal and/or pureed meat. Just two or more servings a day can meet a baby's iron needs at this age. Meats should be home prepared or commercially prepared plain pureed (chopped until smooth in a blender) meats. One tablespoon of red meat per day is enough.
• When your baby is about 6 months of age, include a feeding per day of foods rich in vitamin C with foods that are rich in non-heme iron to improve iron absorption.
• If you can't breast-feed, use iron-fortified formula.
• Don't give low-iron milks (e.g., cow's milk, goat's milk, and soy milk) until your baby is at least 12 months old.
• If your baby was born early or small, talk to your doctor about giving iron drops to your baby.
• If your baby can't get two or more servings per day of iron rich foods (such as iron-fortified cereal or pureed meats), talk to your doctor about giving iron drops to your baby.
• See your doctor for advice on iron supplementation for your baby if you want to continue breast-feeding beyond six months of age.

Young children (aged 1-5 years)

• After your child is one year old, give no more than three 8 ounce servings of whole cow, goat, or soy milk per day. After your child is 2 years old, low fat or nonfat milks should be used in place of whole milks. Vitamin D-fortified milk is a good source of calcium and vitamin D, but not iron.
• Goat's milk, soymilk, fruit juices, cordials and soft drinks can also cause iron deficiency if they replace solid foods in the diet. Strictly limit all milks and juices. Encourage plain water as your child's main source of fluids.
• Don't put your child on a vegetarian diet. Meat, poultry and fish are an important part of your child's daily diet.
• Give your child a diet with iron-rich foods such as iron-fortified breads and iron-fortified cereals and lean meats. See Dietary Sources of Iron.
• Include fruits, vegetables or juices that are rich in vitamin C. Vitamin C helps your child absorb non-heme iron especially when the food that is a source of non-heme iron and the vitamin C-rich food are eaten at the same meal. See Dietary Sources of Vitamin C.
• Chronic diarrhea can deplete your child's iron stores, while intestinal parasites such as worms can cause iron deficiency. See your doctor for prompt diagnosis and treatment.
• Fussy eaters are at risk because their diet is inadequate. Seek advice from your doctor, pediatrician or child health nurse on how to manage a fussy eater.

Adolescent girls and women of childbearing age

• Eat iron-rich foods. See Dietary Sources of Iron.
• Eat foods that are vitamin C sources. Vitamin C helps your body absorb non-heme iron especially when the food that is a source of non-heme iron and the vitamin C-rich food are eaten at the same meal. See Dietary Sources of Vitamin C.
• Eat lean red meats, poultry, and fish. The iron in these foods is easier for your body to absorb than the iron in plant foods.

Pregnant women

• Eat iron-rich foods. See Dietary Sources of Iron.
• Eat foods that are vitamin C sources. Vitamin C helps your body absorb non-heme iron especially when the food that is a source of non-heme iron and the vitamin-C rich food are eaten at the same meal. See Dietary Sources of Vitamin C.
• Eat lean red meats, poultry, and fish. The iron in these foods is easier for your body to absorb than the iron in plant foods.
• Tests to check for anemia should be conducted during pregnancy. If your doctor prescribes iron supplements, take them strictly according to instructions.

How much iron do I need?

The amount of iron your body needs varies depending on your age and gender. It also depends on the amount of iron already stored in your body. If your stored iron is high, your body absorbs less iron from the foods you eat. Conversely, your ability to absorb iron increases when your stored iron is low. Your health care provider can help you determine how much iron is stored in your body and the amount of iron that is necessary to meet your individual needs. If you have already been diagnosed with iron deficiency, talk to your doctor or health care provider about treatment. For healthy individuals, the Recommended Dietary Allowance (RDA) for iron is listed in the following table.

Recommended Dietary Allowance (RDA) for iron by age and sex
Age/Group	Life Stage	Iron (mg/day)
Infants	0-6 months	0.27*
	7-12 months	11
Children	1-3 years	7
	4-8 years	10
Pregnant Women	14-18 years	27
	19-30 years	27
	31-50 years	27
Lactating Women	14-18 years	10
	19-30 years	9
	31-50 years	9

*This value is an Adequate Intake (AI) value. AI is used when there is not enough information known to set a Recommended Dietary Allowance (RDA).

Dietary Sources of Iron

Food Sources of Iron ranked by milligrams of iron per standard amount; also calories in the standard amount. (All amounts listed provide 10% or more of the Recommended Dietary Allowance (RDA) for teenage and adult females, which is 18 mg/day.)

Food, Standard Amount	Iron (mg)	Calories
Clams, canned, drained, 3 oz	23.8	126
*Fortified dry cereals (various), about 1 oz	1.8 to 21.1	54 to 127
Cooked oysters, cooked, 3 oz	10.2	116
Organ meats (liver, giblets), cooked, 3 oz	5.2 to 9.9	134 to 235
*Fortified instant cooked cereals (various), 1 packet	4.9 to 8.1	Varies
*Soybeans, mature, cooked, ½ cup	4.4	149
*Pumpkin and squash seed kernels, roasted, 1 oz	4.2	148
*White beans, canned, ½ cup	3.9	153
*Blackstrap molasses, 1 Tbsp	3.5	47
*Lentils, cooked, ½ cup	3.3	115
*Spinach, cooked from fresh, ½ cup	3.2	21
Beef, chuck, blade roast, cooked, 3 oz	3.1	215
Beef, bottom round, cooked, 3 oz	2.8	182
*Kidney beans, cooked, ½ cup	2.6	112
Sardines, canned in oil, drained, 3 oz	2.5	177
Beef, rib, cooked, 3 oz	2.4	195
*Chickpeas, cooked, ½ cup	2.4	134
Duck, meat only, roasted, 3 oz	2.3	171
Lamb, shoulder, cooked, 3 oz	2.3	237
*Prune juice, ¾ cup	2.3	136
Shrimp, canned, 3 oz	2.3	102
*Cowpeas, cooked, ½ cup	2.2	100
Ground beef, 15% fat, cooked, 3 oz	2.2	212
*Tomato puree, ½ cup	2.2	48
*Lima beans, cooked, ½ cup	2.2	108
*Soybeans, green, cooked, ½ cup	2.2	127
*Navy beans, cooked, ½ cup	2.1	127
*Refried beans, ½ cup	2.1	118
Beef, top sirloin, cooked, 3 oz	2.0	156
*Tomato paste, ¼ cup	2.0	54

Food Sources of iron are ranked by milligrams of iron per standard amount; also calories in the standard amount. (All amounts listed provide 10% or more of the Recommended Dietary Allowance (RDA) for teenage and adult females, which is 18 mg/day.)

*These are non-heme iron sources. To improve absorption, eat these with a vitamin-C rich food.

Source: USDA/HHS Dietary Guidelines for Americans, 2005
Nutrient values from Agricultural Research Service (ARS) Nutrient Database for Standard Reference, Release 17. Foods are from ARS single nutrient reports, sorted in descending order by nutrient content in terms of common household measures. Food items and weights in the single nutrient reports are adapted from those in the 2002 revision of USDA Home and Garden Bulletin No. 72, Nutritive Value of Foods. Mixed dishes and multiple preparations of the same food item have been omitted from this table.

Dietary Sources of Vitamin C

Food, Standard Amount	Vitamin C (mg)	Calories
Guava, raw, ½ cup	188	56
Red bell pepper, raw, ½ cup	142	20
Red bell pepper, cooked, ½ cup	116	19
Kiwi fruit, 1 medium	70	46
Orange, raw, 1 medium	70	62
Orange juice, ¾ cup	61 to 93	79 to 84
Green bell pepper, raw, ½ cup	60	15
Green bell pepper, cooked, ½ cup	51	19
Grapefruit juice, ¾ cup	50 to 70	71 to 86
Vegetable juice cocktail, ¾ cup	50	34
Strawberries, raw, ½ cup	49	27
Brussels sprouts, cooked, ½ cup	48	28
Cantaloupe, ¼ medium	47	51
Papaya, raw, ¼ medium	47	30
Kohlrabi, cooked, ½ cup	45	24
Broccoli, raw, ½ cup	39	15
Edible pod peas, cooked, ½ cup	38	34
Broccoli, cooked, ½ cup	37	26
Sweet potato, canned, ½ cup	34	116
Tomato juice, ¾ cup	33	31
Cauliflower, cooked, ½ cup	28	17
Pineapple, raw, ½ cup	28	37
Kale, cooked, ½ cup	27	18
Mango, ½ cup	23	54

Food sources of vitamin C are ranked by milligrams (mg) of vitamin C per standard amount; also calories in the standard amount. (All amounts listed provide 20% or more of the Recommended Dietary Allowance (RDA) of 90 mg/day for adult men.)

Source: USDA/HHS Dietary Guidelines for Americans, 2005
Nutrient values from Agricultural Research Service (ARS) Nutrient Database for Standard Reference, Release 17. Foods are from ARS single nutrient reports, sorted in descending order by nutrient content in terms of common household measures. Food items and weights in the single nutrient reports are adapted from those in the 2002 revision of USDA Home and Garden Bulletin No. 72, Nutritive Value of Foods. Mixed dishes and multiple preparations of the same food item have been omitted from this table.

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