Iron deficiency anemia
Iron deficiency anemia is the most common type of anemia throughout the world. In the United States, iron deficiency anemia occurs to a lesser extent than in developing countries because of the higher consumption of red meatand the practice of food fortification (addition of iron to foods by the manufacturer). Anemia in the United States is caused by a variety of sources, including excessive losses of iron in menstrual fluids and excessive bleeding in the gastrointestinal tract. In developing countries located in tropical climates, the most common cause of iron deficiency anemia is infestation with hookworm.
Infants are at increased risk for iron deficiency. They are born with a built-in supply of iron, which can be tapped during periods of drinking low-iron milk or formula. Both human milk and cow milk contain rather low levels of iron (0.5-1.0 mg iron/liter). However, the iron in human milk is about 50% absorbed by the infant, while the iron of cow milk is only 10% absorbed. During the first six months of life, a baby's growth is made possible by the milk in the diet and by the infant's built-in supply. However, premature infants havea lower supply of iron and, for this reason, it is recommended that pre-terminfants (beginning at 2 months of age) be given oral supplements of 7 mg iron/day, as ferrous sulfate. Iron deficiency can result if an infant is fed a formula based on unfortified cow milk.
Blood is lost from the body every day through the feces. The normal rate of this loss is 0.5-1.0 ml per day. However, more blood can be lost if colon or rectal cancer is present. About 60% of colorectal cancers result in further blood losses, where the extent of blood loss is 2-10 ml/day, and can lead to iron deficiency anemia.
Infection with hookworm can provoke iron deficiency and iron deficiency anemia. The hookworm is a parasitic worm that thrives in warm climates, includingin the southern United States. It enters the body through the skin, as through bare feet. The hookworm then migrates to the small intestines where it attaches itself to the villi, the small sausage-shaped structures in the intestines that absorb nutrients. The hookworms damage the villi, resulting in bloodloss, and they produce anti-coagulants that cause continued bleeding. Each worm can cause the loss of up to 0.25 ml of blood per day.
Bleeding and blood losses through gastrointestinal tract can also be caused by hemorrhoids, anal fissures, irritable bowel syndrome, and blood clotting disorders.
Symptoms of iron deficiency anemia include weakness and fatigue. These symptoms result because the red blood cells do not function properly and cannot carry oxygen to the muscles. Iron deficiency can also affect other tissues, including the tongue and fingernails. Prolonged iron deficiency can make the tongue smooth, shiny, and reddened, a condition called glossitis. The fingernailsmay grow abnormally and acquire a spoon-shaped appearance.
Decreased iron intake contributes to iron deficiency. The iron content of food varies widely; cabbage, for example, contains about 1.6 mg of iron per kg,spinach contains 33 mg/kg. Apples, tomatoes, and vegetable oil are relativelylow in iron, while whole wheat bread and beef are relatively high in iron. Whether a food is low or high in iron can also be determined by comparing itsiron content with the recommended dietary allowance (RDA) for iron. The RDA for iron for the adult male is 10 mg/day, while that for the adult woman is 15mg/day. The RDA during pregnancy is 30 mg/day. The RDA for infants of up tosix months years of age is 6 mg/day, while that for infants of between six months and one year is 10 mg/day. The RDA values are based on the assumption that the person eats a mixture of plant and animal foods.
Oral iron supplements (pills) can be used to treat iron deficiency anemia. They may contain various iron salts, such as ferrous sulfate, ferrous gluconate, or ferrous fumarate. Injections and infusions of iron (which may be necessary if oral supplements fail) involve iron dextran. In patients with poor ironabsorption (by the gut), therapy with injection or infusion is preferable over oral supplements. Treatment of iron deficiency anemia sometimes requires more than therapy with iron. If the deficiency was provoked by hemorrhoids, surgery may prove essential to prevent recurrent iron deficiency anemia. Likewise, a deficiency caused by hookworm infestations should involve eliminating the parasite. The prognosis for treating and curing iron deficiency anemia isexcellent. As long as the patient takes the iron supplements as directed. Iron deficiency anemia in infants and young children can be prevented by the useof fortified foods, such as formula and cereal.