Marie Spano

The Fatigue Fighting Nutrient: Iron

Marie Spano, MS, RD, CSCS

If you feel like your energy levels are low, you’re lacking motivation and you could fall asleep at your desk everyday, don’t blame your job right away. Instead, take a close look at the signs and symptoms of iron deficiency.

Iron deficiency is the most prevalent nutrition deficiency in the world. It occurs when the body’s stores of iron are low (the stage prior to anemia), and, it may or may not cause any symptoms. Iron deficiency disproportionately affects those in developing countries but it is also prevalent in industrialized countries. According to the World Health Organization, up to 80% of the world’s population may be iron deficientⁱ and over 30% of the world’s population may meet the criteria for iron deficiency anemiaⁱⁱ. Iron deficiency anemia develops when low iron stores persist for a period of time and the body cannot make enough healthy red blood cells to deliver oxygen throughout the body.ⁱⁱⁱ

In the United States, the largest nationwide survey, the National Nutrition and Health Examination Surveys (NHANES) found that approximately 16% of teenage girls aged 16-19 and 12% of women aged 20-49 are deficient in iron^iv. These numbers are staggering in a country with an abundant food supply and an array of multivitamin and iron supplements.

Are You at Risk?

Iron deficiency occurs in stages. First, your iron intake stops meeting your daily needs. Next, this negative balance takes a toll on your iron stores – the supply your body digs into when you aren’t getting enough from your diet. By the time you hit iron deficiency anemia, your storage iron is low and your blood levels of iron cannot meet your daily needs. Your hemoglobin, the protein in your red blood cells (RBCs) that carries oxygen to your body’s tissues, levels drop, signaling anemia.

Women of childbearing age, teenage girls, pregnant women, infants and toddlers have the greatest need for iron and therefore an increased risk of becoming deficient. You have an increased risk for iron deficiency anemia if you meet one or more of the following criteria:

Dietary iron intake is low Vegetarian athlete Female athlete Distance runner Significant blood loss from menstruation

Celiac disease Crohn’s disease Gastric bypass surgery Excessive antacid intake

Signs and Symptoms of Iron Deficiency Anemia

When you hear the word anemia, you probably think of iron deficiency anemia. However, there are many types of anemia as this term simply refers to the body’s deprivation of oxygen. Our red blood cells carry oxygen throughout our body and when their function is compromised we can become anemic. The most common types of anemia in adults are iron deficiency anemia, megaloblastic (pernicious) anemia – due to folic acid deficiency or macrocytic anemia – deficiency of B12.

The signs and symptoms of iron deficiency anemia in adults include6:

• feeling tired and weak
• work performance suffers
• feeling cold often
• inflamed tongue (glossitis)
• shortness of breath during routine activities
• pica – desire to eat non-food substances such as laundry starch, dirt, clay, ice

Getting More Iron

If you think your diet falls short, how can you get more iron? Luckily, iron is found in a number of different foods and in cast iron pots. But, not all of this iron is well absorbed. Though spinach worked for Popeye, it won’t work very well for you. Several factors affect the amount of iron absorbed by an individual^v. The biggest factor influencing iron absorption is your storage levels of iron. If iron stores are high, absorption levels drop. However, if storage is low, absorption increases in an effort to build optimal storage levels^iv. The other big factor affecting iron absorption is the type of iron you consume.

The two types of iron are heme and non-heme iron. Heme iron, derived from hemoglobin, is found in foods that contained hemoglobin - animal foods including red meats, fish and poultry. A serving of chicken livers, clams, or roasted beef tenderloin contains all the iron you need for a day. Heme iron is absorbed better than non-heme iron and absorption isn’t affected by anything else you eat. We absorb approximately 15-35% of the heme iron we eat.^vi

Non-heme iron is the form of iron found in all other, non-meat based foods including vegetables, grains and iron-fortified breakfast cereal. Non-heme iron is not absorbed as well as heme iron. Only 2 – 20% of nonheme iron is absorbed^vii. And, while heme iron is not affected by other food eaten concurrently, there are many factors that affect the absorption of non-heme iron. For instance, the non-heme iron in Popeye’s spinach is bound to a substance called phytic acid, the storage form of phosphorus in plants. Phytic acid decreases the absorption of non-heme iron. In addition, several other substances decrease the absorption of non-heme iron including:

• tannins (found in tea and wine)
• calcium (dairy, multivitamins)
• polyphenols
• phytates (legumes, whole grains)
• some proteins in soy food^v

You can increase the amount of non-heme iron you absorb by consuming vitamin C rich foods or beverages at the same time or consuming a non-heme source at the same time you eat your heme iron (from meat, turkey, chicken and fish).

There is something to the power of a good partnership. If you want to increase your absorption of non-heme iron, pair the following together:

Pair this non-heme source with		This to increase absorption:
Peanut butter sandwich on whole wheat bread		An orange
Brown rice		Chicken (think stirfry!)
Iron fortified cereal		Sliced strawberries
Black beans		Chicken or beef (a burrito works wonders)
Spinach salad		Red bell pepper, slices of oranges
Bean soup		Ham

Testing for Iron Deficiency

If you think you aren’t getting enough iron through your food and you can just pop a pill, think again. It’s always a good idea to talk to your physician first, and actually get tested, prior to taking an iron supplement (to make sure what ails you is iron deficiency and not something else).

Your physician will likely order a complete blood count (CBC), a test that will assess both hemoglobin and hemotocrit and provide a closer look at your red blood cells. In addition, your doctor may order additional iron tests.

Iron Tests^{viii, ix, x}

	Measures	Normal Range	In Iron deficiency anemia
Hemoglobin	The protein in RBCs that carries oxygen.	F: 12.1 – 15.1 gm/dL M: 13.8 – 17.2 gm/dL	Low
Hematocrit	The percentage of RBCs found in a blood sample. (this depends on the total number of RBCs and size of the RBCs)	F: 36.1 – 44.3% M: 40.7 – 50.3%	Low
Serum Iron	The amount of iron in your blood. This value may be normal even if your iron stores are low.	60- 170 mcg/dL	Low
Serum ferritin	Measures your iron stores. When your ferritin is low, you are very iron deficient.	F: 12 – 150 ng/mL M: 15 – 200 ng/mL	Low
Transferrin	Transferrin is a protein that carries iron in your blood. With anemia, you’ll have a high level of transferrin that is not carrying iron.	200-400 mg/dL	High
TIBC (total iron binding capacity)	Measures how much transferring in the blood is not carrying iron.	240 – 450 mcg/dL	High

Always get tested to be sure you are deficient prior to taking a supplement. Iron is not excreted from the body but instead stored in body tissues and organs when you have plenty of iron already. Therefore, excess iron can be toxic.

It isn’t worth it to feel cold and tired all the time. So if you think you need more iron, get tested. And if your doctor prescribes iron, ask about heme iron supplements. You’ll need less to boost your stores, which will also decrease the likelihood of that all too common complaint with iron supplements: constipation. And, you won’t have to worry about when you take your supplement. After all, if it isn’t easy and makes you feel worse (by being constipated), you are less likely to continue taking it. And then you are right back where you started!

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ⁱ Stoltzfus RJ. Defining iron-deficiency anemia in public health terms: reexamining the nature and magnitude of the public health problem. J Nutr 2001;131:565S-7S.
ⁱⁱ Micronutrient deficiencies. Iron deficiency anaemia. World Health Organization. http://www.who.int/nutrition/topics/ida/en/index.html
ⁱⁱⁱ Iron Deficiency Anemia. National Anemia Action Council. http://www.anemia.org/patients/faq/#ida
^iv Iron Deficiency. MMWR Weekly. CDC. 2002;51(40):897-899. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5140a1.htm#tab1
^v Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium and Zinc. Washington, DC: National Academy Press, 2001.
^viMonson ER. Iron and absorption: dietary factors which impact iron bioavailability. J Am Dietet Assoc. 1988;88:786-90.
^viiTapiero H, Gate L, Tew KD. Iron: deficiencies and requirements. Biomed Pharmacother. 2001;55:324-32.
^viiiPronsky ZM. Food Medication Interactions, 10th edition 1997.
^ixHeomglobin. Medline Plus. http://www.nlm.nih.gov/medlineplus/ency/article/003645.htm
^x Hematocrit. Medline Plus. http://www.nlm.nih.gov/medlineplus/ency/article/003646.htm