Iron dietary requirements

Example 1.—A classical problem of linear programming is the diet problem. Given minimal needs for vitamins, iron, calcium, phosphorous etc., which are present in known proportions in a variety of possible foods with given prices, it is desired to determine a diet from these foods that meets the minimal needs for the vitamins and other ingredients at the lowest cost. To illustrate with a simple example and hypothetical figures, denote three types of food by Flt F2, F3, and two types of dietary requirements, e.g., vitamins by A and B. The table... 

The excess dietary iron is derived from a traditional fermented maize beverage that is home-brewed in steel drums.114 It should be noted in this connection that the body has no mechanism for the excretion of iron, and except for women in the child-bearing years, the dietary requirement for iron is extremely low. 

In human diets, leavening of bread and exposure of cereals to wet heat lower the phytate content, increasing zinc avahability. Other factors, such as dietary fiber and a constituent of beans, can also lower zinc intestinal absorption but to a lesser extent. Iron at supplemental dosages (up to 65 mg/day) may decrease zinc absorption so that pregnant and lactating women taking iron may require zinc supplementation, ... 

The dietary requirement for iron depends on the amount and composition of the food, the amount of iron lost from the body, and variations in physiological state such as growth, onset of menses, and pregnancy. The average North American diet contains about 6 mg of iron per 1000 calories and supplies about 10-15 mg/d. Of that ingested, 8-10% (1-1.5 mg/d) is absorbed. Thus, dietary factors that affect absorption are more important than the iron content of the diet and may be more important for correction of iron deficiency than addition of iron to the diet. 

Iron, whether in the form Fe(II) or Fe(III), is usually found in the body in association with proteins. Little or no iron can be found free in the blood. Because iron-containing proteins are ubiquitous, there is a dietary requirement for this mineral. Severe deficits can lead to iron-deficiency anemia. 

Description. Every cell in the body requires iron for a variety of functions. This versatile mineral is involved in oxygen transport (hemoglobin) and storage (myoglobin), is required by enzymes that produce energy for the cell, and it plays an important role in the function of the immune and central nervous systems. Iron is required in relatively high doses to maintain proper nutrition. Of aU the nutrients, the allowance for iron is the most difficult to obtain from dietary sources, aud therefore is the most common single micronutrient deficiency in the world. ... 

In view of the conservation of iron by the body, estimation of requirement is difficult. Heath and Patek have calculated, from estimates of the iron required to build body tissue and to replace loss, that the total amount needed by males from birth to 21 years is 3.148 g., and by females from birth to 47 years, 12.222 g. These figures do not represent dietary requirement. Moore and Dubach have suggested that the normal adult male must assimilate 0.5 to 1 mg. of iron daily to maintain balance, the adult female about 1 to 2 mg. daily. If only 10 % of the iron in food is absorbed, the diet should furnish 10 to 15 mg. of iron daily. Recommended allowances of the Food and Nutrition Board are of this order (Table 1). 

At first, new foods are given in addition to milk feeds and should be in puree form, but as the quantity increases they replace the milk feeds and their nutritional value is of more importance. After 4 months, dietary iron is required and should be introduced as dark green vegetable puree, iron-containing cereals, liver, red meat and (later) egg yolk. Protein quality and protein energy ratio in the solids must be adequate. In the third world and in vegetarian diets, nutritionally adequate mixtures of appropriate local foods are essential. 

Trace elements are those elements of the periodic table that occur in animals or humans in amounts measured in mg per kg of body weight or less. The trace elements essential for health are usually required by humans in amounts measured in mg per day these elements include copper, iron, manganese, and zinc. The individual trace elements are discussed elsewhere in the encyclopedia. Since 1980, the term ultratrace element has appeared in the nutritional literature. Ultratrace elements have been defined as those elements with estimated dietary requirements usually less than Imgkg, and often less than 50pgkg of diet for laboratory animals. For humans, the term often is used to indicate an element with an established, estimated, or suspected requirement of less than 1 mg per day or generally indicated by pg per day. At least 18 elements could... 

Cobalt, copper, molybdenum, iodine, iron, manganese, nickel, selenium, and zinc are sometimes provided to mminants. Mineral deficiency or toxicity in sheep, especially copper and selenium, is a common example of dietary mineral imbalance (21). Other elements may be required for optimal mminant performance (22). ExceUent reviews of trace elements are available (5,22). 

A system of internal iron exchange exists which is dominated by the iron required for hemoglobin synthesis. For formation of red blood cells, iron stores can furnish 10—40 mg/d of iron, as compared to 1—3 mg from dietary sources (74). Only ca 10 wt % of ingested iron actually is absorbed. 

Iron deficiency affects more than 1.7 billion people worldwide and has been called the most widespread health problem in the world by the World Health Organization. Due to severe iron deficiency, more than 60 000 women die in pregnancy and childbirth each year, and almost 500 million women of childbearing age suffer from anemia. Dietary iron requirements depend on mrmerous factors, for example, age, sex, and diet composition. Recommended daily intake in the USA varies dependent on gender and age. Potato is a modest source of iron. A study of cultivated varieties showed 0.3-2.3 mg of Fe in a 100 g tuber (True et al., 1978). Ranges of iron content from 6 to 158 p,g/g of DW have been reported (Andre et al., 2007 Wills et al.. 

What mass of 3.0 wt% H202 solution is required to provide a 50% excess of reagent for Reaction 1-5 with 12 dietary iron tablets ... 

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