How do I know if I’m getting too much or too little iron?

Either too much or too little iron can get you into big trouble.

In this country, health-conscious people may take too much iron rather than not enough. The current recommended dietary allowances of the U.S. National Research Council for iron are:

• Infants, up to 6 months — 6 milligrams per day.
• Infants, 6 months to 1 year — 10 milligrams per day.
• Children, 1 year old to 10 years old — 10 milligrams per day.
• Males, 11 years old to 18 years old — 12 milligrams per day.
• Males, 19 years to older than 50 — 10 milligrams per day.
• Females, 11 years old to 50 years old — 15 milligrams per day.
• Females, 51 years old and older: 10 milligrams per day.
• Pregnant women — 30 milligrams per day.
• Lactating women — 15 milligrams per day.

The Tolerable Upper Intake Level for adults is 45 milligrams per day of iron, a level based on gastrointestinal distress as an adverse effect. Iron supplements at several times the RDA levels may be dangerous for those who absorb iron too easily.

Iron deficiency most commonly manifests itself as iron deficiency anemia. Iron deficiency and iron deficiency anemia can occur during periods of rapid growth, during pregnancy and among women who are menstruating more than usual. It also can be associated with any type of intestinal loss of blood, frequent donation of blood and from the inability to absorb iron efficiently.

Initial symptoms of iron deficiency anemia are fatigue and lack of energy. Dizziness, weight loss and lowered immunity also can occur. The symptoms can be alleviated once the cause of the iron deficiency has been determined.

It is unlikely that iron toxicity can develop from an increased dietary intake of iron alone. Children have been known to develop iron toxicity by increased intake of iron supplements, however. Symptoms of iron toxicity are fatigue, anorexia, dizziness, nausea, vomiting, headache, weight loss, shortness of breath and possibly a grayish color to the skin.

Hemochromatosis is a genetic disorder that affects the regulation of iron absorption. The incidence may be as high as 5 in 1,000 in caucasians. Treatment consists of a low-iron diet, no iron supplements and phlebotomy (blood removal) on a regular basis.

Excess storage of iron in the body is known as hemosiderosis. The increased iron stores come from the consumption of excessive iron supplements or from receiving frequent blood transfusions, not from increased iron intake in the diet.

What are the best food sources of iron?

The best food sources of easily absorbed iron are animal products (heme iron). Iron from vegetables, fruits, grains and supplements (nonheme iron) is harder for the body to absorb. If you mix some lean meat, fish, or poultry with beans or dark leafy greens at a meal, you can improve absorption of vegetable sources of iron up to three times. Foods rich in vitamin C also increase iron absorption.

Some foods decrease iron absorption. Commercial black or pekoe teas contain substances that bind to iron so it cannot be used by the body. The evaluation of absorbable iron in a food is a more accurate way to calculate iron available to the body than by simply recording the total iron content.

Iron sources that have high iron availability are: oysters, liver, lean red meat (especially beef), poultry, dark red meat, tuna fish, salmon, iron fortified cereals, dried beans, whole grains, eggs (especially egg yolks), dried fruits, and dark leafy green vegetables. Reasonable amounts are also found in lamb, pork, and shellfish.

Nonheme iron is found in: whole grains such as wheat, millet, oats, and brown rice; lima beans, soybeans, dried beans and peas, kidney beans; seeds such as almonds and Brazil nuts; prunes, raisins, and dried apricots; and broccoli, spinach, kale, collards, asparagus, and dandelion greens.

What are the main functions of iron?

The mineral iron is an essential nutrient for humans because it is part of blood cells, which carry oxygen to all body cells.

About 30 percent of the iron in our bodies is in storage to be readily available to replace lost iron.

Iron is essential to the formation of hemoglobin and myoglobin, which carry the oxygen in the blood and the muscle. It also makes up part of many proteins and enzymes in the body.

Iron deficiency is the most common nutritional deficiency worldwide. Although full-blown anemia is rarely evident, partial deficiency is widespread.

Symptoms of decreased iron stores include general fatigue, shortness of breath, headache, irritability, and/or lethargy. If you have constant unusual signs of tiredness, see your doctor. There are many causes of such symptoms.

Simply taking an iron supplement may not be the key to renewing your energy.

Who is most at risk of having low iron?

Those at risk for low iron stores include:

• Women of child bearing age due to menstruation.
• Pregnant women due to baby’s needs and blood loss during childbirth.
• Infants. They usually are born with iron stores to last about six months. An infant’s iron needs are met by breast milk. A bottle fed infant’s iron needs can be met with an iron supplement or iron-fortified infant formula. As babies move to solid foods, foods containing high amounts of iron should be selected to prevent the development of iron deficiency.
• Children between one and four years of age are at risk for developing iron deficiency because of rapid growth and a lack of sufficient iron in their diets unless iron-fortified foods or a supplement is available.

Milk is a very poor source of iron. Children who drink large quantities of milk at the expense of other foods may develop “milk anemia.” Limit milk to about one quart or less per day. Recommended milk intake is two to three cups per day for toddlers.

• Adolescents — both boys and girls — traditionally have been prone to anemia because of rapid growth rates, erratic eating habits and concerns about body image.
• Other groups at higher than average risk are long-distance runners whose demanding exertions may somehow damage red blood cells, and strict vegetarians because they do not eat animal products which contain the most bioavailable form of iron.

— Susan Krumm is an Extension agent in family and consumer sciences with K-State Research and Extension-Douglas County, 2110 Harper St. She can be reached at 843-7058.