Are you getting enough iron?

The Feedzone with Monique Ryan: Are you getting enough iron?
Adequate intake is essential to prepare for the 2007 season.
By Monique Ryan, MS, RD
This report filed February 21, 2007

Cyclists in many parts of the country are ready to leave behind long rides on the trainer and eagerly await warmer weather and putting in some quality road miles. As you continue to train and prepare for the 2007 season, don't ignore a small, but essential component of your training diet. Adequate iron intake and optimal iron stores are essential to putting in full efforts on the bike. Low iron stores can impair athletic performance, and correcting iron deficiency that has led to full blown anemia, can take several months to correct, potentially bringing an unwelcome halt to your training and racing program.

Why you need iron
Iron is required for a number of important exercise related functions in the body. It is an important component of hemoglobin, which transports oxygen in the blood. Iron is also an important component of myoglobin, which transports oxygen in the muscles. Many muscle enzymes involved in metabolism require iron, and other iron compounds facilitate oxygen use at the cellular level. And if that weren't enough to convince you that you should pay attention to this all-important mineral, iron is also required for red blood cell production and is essential to maintaining a healthy immune system.

Data clearly indicates that true iron-deficiency anemia, the extreme of low iron stores in the body, will impair your performance. Although we have limited data on the performance effects of early iron deficiency (before true anemia develops), some newer research suggests that correcting this state can also prevent a downturn in performance. Of course, it is also prudent to treat early iron deficiency in order to prevent the more serious condition of anemia from developing.

Getting checked
Your body's storage form of iron, ferritin, is used as an indicator of iron stores, as are other iron measures- serum iron, transferrin, transferrin saturation, hemoglobin, and hematocrit. About 30 percent of iron is in storage form and the remaining 70 percent of your iron is involved in oxygen transport.

Many athletes have these iron-related values checked regularly at various points in their training and competitive season. A skilled practitioner can evaluate these values in conjunction with a dietary assessment and ongoing monitoring. At this point in the season, it would be prudent to obtain some baseline values, particularly if you have not had them checked in sometime. Regular monitoring of blood work can then reveal individual trends and potential problems. Iron depletion is a continuous process that can eventually result in iron deficiency anemia, a condition under which your ability to manufacture hemoglobin and red blood cells is limited. If not detected early, iron depletion can easily lead to anemia.

Endurance training can also affect your blood measurements of iron. Training produces an increased blood volume, which dilutes hemoglobin, making it appear low in some athletes when iron stores are adequate. This increased blood volume usually occurs at the beginning of serious training and is another reason why it is so important to check several iron stores and monitor individual changes.

Why you might be at risk
Inadequate dietary intake of iron is the most common cause of iron deficiency and anemia. As a cyclist you do have high iron requirements and need to maintain a high level of red blood cells. Younger cyclists also have higher iron needs during periods of growth. Iron losses can also aggravate iron balance. Iron is lost in sweat, and the higher your sweat rate, the greater your iron losses. Strenuous training can also precipitate gastrointestinal bleeding from minor damage to the stomach and intestinal lining. Habitual use of anti-inflammatory drugs can also cause some gastrointestinal blood loss. For cyclists who cross train, repeated pounding of the feet on hard surfaces, such as when running, can also destroy red blood cells. Training at altitude can also place you at risk for iron deficiency.

Iron in your diet
Our bodies can't manufacture iron, so we do need to obtain this mineral from our diet. Development of iron deficiency is associated with low calorie diets, diets with limited amounts of animal protein, poorly planned vegetarian diets, and various types of fad or unbalanced diets.

Iron is actually found in a variety of foods, but some foods are more concentrated sources of iron, and some have a better "bioavailability," or simply provide a better absorbed form of iron. The best food sources of iron provide an ample amount of this trace mineral and in a well-absorbed form. Many foods are also fortified with iron. Heme iron, found in animal foods such as lean meat, poultry, and seafood is the best absorbed form with a 10 to 30 percent absorption rate, while non-heme iron found in plant foods such as dried peas and beans, and whole grains, has a 2 to 10 percent absorption rate.

They are several ways to increase your iron intake and maximize your iron absorption. Consuming meat and plant iron sources together can enhance iron absorption from plant foods. Small amounts of red meat or poultry in bean chili, spinach with chicken, and turkey in lentil soup are examples of combining heme and non-heme iron. Vitamin C containing foods also enhance plant iron absorption. Try having orange juice or strawberries with an iron-fortified cereal.

To boost iron intake and absorption, you can also:

• Incorporate small amounts of lean red meat into your diet.
• Add small amounts of red meats to stir-fries, soups, pasta sauces, and casseroles.
• Mix heme iron foods with non-heme iron foods.
• Incorporate iron fortified cereals into your diet. Avoid cereals with a high bran content, as they contain phytic acid, which binds with iron and decreases absorption.
• Add more fish and shellfish to your diet for their iron content.
• Avoid drinking strong tea and coffee with iron-rich meals, as they can inhibit iron absorption.

Iron Content (mg) of Selected Foods
Sources of Heme Iron Iron
Liver, beef, cooked, 3 oz. 100 g) 6.0
Beef, cooked, 3 oz. (100 g ) 3.5
Pork, cooked, 3 oz. (100 g) 3.4
Shrimp, cooked, 3 oz. (100 g) 2.6
Turkey, dark, cooked, 3 oz. (100 g) 2.0
Chicken, breast, cooked, 3 oz. (100g) 1.0
Tuna, light, 3 oz. (100 g) 1.0
Flounder, sole, salmon, 3 oz. (100 g) 1.0

Sources of Plant Iron Iron
Cereal, iron-fortified, 1 oz (30 g) 2-18
Cream of wheat, 3/4 c. (200 ml) 9
Lentils, 1 c. (240 ml) 6
Instant breakfast, 1 envelope 4.5
Kidney beans, canned, 1 c. (240 ml) 3.2
Baked potato, with skin, 1 3.0
Prune juice, 8 oz. (240 ml) 3.0
Wheat germ, 1/4 c. (60 ml) 2.6
Apricots, dried, 10 halves 1.7
Spaghetti, enriched, cooked, 1/2 c. (120 ml) 1.4
Bread, enriched, 1 slice 1.0

Iron Supplementation
Besides an iron rich diet, iron supplementation may be needed to bring back iron stores to normal. Athletes are typically supplemented with 100 to 300 milligrams of iron combined with vitamin C to enhance absorption. Iron supplementation should always be done with regular medical monitoring. You should never diagnose an iron deficiency on your own or supplement to prevent a perceived deficiency. While the amounts of iron found in a basic multivitamin mineral supplement are modest, ranging, from 8 to 18 milligrams, higher doses can pose some risk. High doses of unneeded iron can actually compromise your immune system, and could interfere with zinc and copper absorption. A small percentage of people also have a condition called hemochromatosis. In this potentially dangerous condition iron accumulates in your tissues and organs often causing irreparable damage. This condition can go undiagnosed for many years, and is aggravated by unneeded iron supplementation.