Dietary Iron Intakes and Circulating Levels of Hemoglobin in African American Women and Their Biological Daughters

Document Type


Publication Date

Winter 2003

Publication Source

Topics in Clinical Nutrition


The purpose of this study was to determine dietary iron and hemoglobin levels using 24-hour food recalls, food frequency data, and blood samples drawn from African American women (n = 42) and their biological daughters (n = 66). Nutrition information was entered into Nutritionist V software to determine intake and to compare to the daily recommended intake for iron. Correlations were made between hemoglobin levels in the blood and dietary iron intakes. Results indicated individuals aged 19–30 and 31–50 were significantly low in dietary iron (P < .0001). The average hemoglobin level of participations was 12.9 (±0.99) g/dL (P < .001). Daughters' hemoglobin levels were higher compared to their mothers'. There was no relationship between mothers' and daughters' hemoglobin status.

IRON DEFICIENCY is present in 30% of the world's population and is the most common nutritional deficiency in the United States. 1 Researchers have documented that females are at greater risk for iron deficiency than are males. In the United States alone, nearly 8 million women are iron-deficient and 3.3 million women have iron deficiency anemia. 2 Menstruation causes an increased need of 0.56 mg of iron per day. 2 Needs are greater for pregnant women than for nonpregnant women. Men and postmenopausal women are at little risk for iron deficiency. 3 It has been documented that iron deficiencies are more prevalent among African Americans than among Caucasians. Information regarding iron deficiency in African Americans is limited.

Iron is stored in the body as the soluble protein complex ferritin or as the insoluble protein complex hemosiderin in the liver, bone marrow, spleen, and skeletal muscles. 3,4 Stored iron is available to the body should dietary iron fail to meet needs. 5 If a negative iron balance occurs, the body's stores may become depleted. 5 When there is a net negative iron balance, iron deficiency occurs in 3 stages. The first stage is iron depletion: stored iron is reduced, but functional iron may not be affected. 4 The next stage is iron deficiency, indicating a difference between the body's need and the amount of iron actually stored. 4,6 The last and most severe stage is iron deficiency anemia. Iron deficiency anemia is present when hemoglobin concentrations of females over the age of 18 years are below 12.0 g/dL, 3 of females between 12 and 15 years are at or below 11.8 g/dL, 3 of females between 8 and 12 years are below 11.9 g/dL, 3 and of females between 5 and 8 years are below 11.5 g/dL. 3

Lack of iron can have many possible physiological side effects. Iron functions to facilitate the use and storage of oxygen in muscle 4; low iron counts can be a factor in decreased oxygen utilization. Iron deficiency anemia causes interference with the body's ability to carry oxygen. Iron deficiency anemia also leads to developmental delays in preschool children and behavioral problems throughout their educational career. 3 Another health risk posed by the deficiency of iron is that of a compromised immune system. 2,6 A deficiency in iron may be detrimental to optimal functioning of the body's defense cells, thus lowering the body's resistance against infection. 6 Iron also functions as an enzyme in several tissues and as an interactor in cellular metabolism though its interaction with cytochromes. 4 Without sufficient iron, the body struggles with functions of gene transcription (DNA synthesis) and nuclear metabolism. 2

Clearly, iron levels in the body need to be maintained for optimal health. When they are not, the cause may be diet, due to limited access to food or simply a low iron diet, or a medical condition such as a bleeding disorder. 3 For women, heavy menstrual blood loss and the use of an intrauterine device are further risk factors. 3,4

The bioavailability of iron consumed is an important factor to consider. Heme iron is 2 to 3 times more absorbable than non-heme iron. Heme iron can be found in meat, poultry, and fish, whereas non-heme iron is found in plant-based and iron-fortified foods. 3 Cereals and flours have been fortified with iron ranging from 8% to 100% of its daily value. 7 When an individual does not consume foods such as these, or consumes high fat, low nutrient-dense foods, the required intake of iron may not be met.

It is known that iron deficiency is common in the United States, caused mainly by diets deficient in iron. 4 However, it has also been shown that there is a high rate of anemia in inner-city African American children, 8 which could indicate iron deficiency. A search of the current literature did not yield information about the iron status of African American women, although information is available for the iron status of females in general, which is why it is useful to study African American women and children, namely their daughters, in this study. The iron intakes of African American women and children need to be examined in order to make an effort to ensure that their nutritional needs are being met. Therefore, the purpose of this study was to determine the dietary iron intakes and their correlation to levels of hemoglobin, specifically for African American women (over 18 years of age) and their biological daughters (between the ages of 4 and 18 years).

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