Iron balance

An impressive number of proteins that are involved in iron transport have been identified in recent years (Andrews, 1999 Griffiths et al., 1999). Most of them can either be up-regulated or down-regulated in situations of iron deficiency and different forms of iron overload, in order to maintain a safe iron balance. However, variations in the absolute levels or genetic defects of these proteins may cause iron overload or iron deficiency. In many forms of iron-related pathology detailed information can be obtained using appropriate animal models. 

Metal (iron) balance Slag balance Carbon balance Gas balance... 

Utilization of iron was not affected at levels of 9 to 26g bran/day from corn or wheat (19, 2J0 2 ) or bY 16 g of bran/day (25). Negative balances were observed by Morris and Ellis (21) during the first balance period with daily intakes of 36g bran but not during the second 5-day balance period. However, Simpson et al. (24) found a marked inhibition of non-heme iron absorption from a single test meal which included 6 g of wheat bran. With a diet which provided 35g/day of NDF (neutral detergent fiber from bran bread), iron balances were decreased (26) compared to the 9 or 22g/day intake levels. 

Kelsay and co-workers (27,28) observed no effects on iron balance of including 24g/day of NDF from fruits and vegetables however, negative zinc and copper balances were observed. In a second study (29), lower zinc, but not copper, balances were observed at intakes of 25g NDF/day lower intakes (10, 18g NDF) had no effect. In these studies, the effects of oxalates (from spinach) may have affected mineral balances. In a third study, a combination of consuming spinach every other day plus a daily fiber intake of 26g NDF resulted in increased fecal zinc excretion and negative balances (22) ... 

Significantly decreased iron balances with soy isolate diet tendency for zinc balances to decrease with increased phytic acid level (40)... 

Simpson et al. (24) did not observe increased non-heme iron absorption when dephytinzed bran was included in a test meal compared to the non-dephytinized bran. Removal of phytic acid from soy protein likewise did not improve non-heme absorption (38). Decreased iron balances, observed by Bodwell et al. (40) with soy isolate diets, did not appear to be associated with the level of phytic acid a tendency for zinc balances to decrease with increased phytic acid was observed. 

Chronic iron intake Individuals with normal iron balance should not take iron chronically. 

Wisker E, R. Nagel, T. K. Tanudjaja, and W. Feldheim. Calcium, magnesium, zinc, and iron balances in young women effects of a low-phytate barley-fiber concentrate. Am J Clin Nutr 1991 54(3) 553-559. 

There is no mechanism for excretion of iron. Small amounts are lost in the feces by exfoliation of intestinal mucosal cells, and trace amounts are excreted in bile, urine, and sweat. These losses account for no more than 1 mg of iron per day. Because the body s ability to excrete iron is so limited, regulation of iron balance must be achieved by changing intestinal absorption and storage of iron, in response to the body s needs. As noted below, impaired regulation of iron absorption leads to serious pathology. 

A titanium metal base alloy consisting essentially by weight of about 0.6% to 0.9% nickel, 0.2% to 0.4% molybdenum, up to 0.2% maximum iron, balance titanium, said alloy being characterized by good corrosion resistance in hot brine environments. 

A titanium base alloy as set forth in claim 1 having up to 0.1% iron, balance titanium. 

Iron is stored in intestinal mucosal cells as ferritin (an iron/protein complex) until needed by the body. Iron deficiency results from acute or chronic blood loss, from insufficient intake during periods of accelerated growth in children, or in heavily menstruating or pregnant women. Therefore it essentially results from a negative iron balance due to depletion of iron stores and inadequate intake, culminating in hypochromic microcytic anemia. Supplementation with ferrous sulfate is required to correct the deficiency. Gastrointestinal disturbances caused by local irritation are the most common adverse effects caused by iron supplements. 

There are several inherited diseases which are associated with the gradual excess accumulation of iron via the gut. Hereditary haemochromatosis is a relatively rare condition in which iron absorption is increased through an unidentified mechanism. This condition usually presents in the fourth or fifth decade of life with the secondary effects of iron overload such as heart failure, liver cirrhosis or sugar diabetes. As the production of red cells is unaffected, the excess iron can be removed slowly by venesecting a unit of blood every week for up to two years. However, in the acute situation, iron chelation may be used to remove toxic low-molecular-weight iron until sufficient negative iron balance has been obtained by venesection. 

Biliary excretion of copper and iron is important. Major losses of iron can be caused by internal bleeding. Thus women during their menstrual periods will be in negative iron balance unless proper nutrition is observed. Blood loss via the gastrointestinal tract, as in ulcers or some forms of cancer, leads quickly to loss of utilizable or stored iron. ... 

Menstrual loss is about 30 mg. period menstruating women may therefore be in negative iron balance. 

Iron balance is determined by the difference between iron absorption and iron loss. Humans lack a mechanism to excrete excess iron and physiological control of iron balance is achieved by regulation of absorption. There is a reciprocal relationship between stores and absorption so that, as stores decline absorption increases and vice versa. 

The paramount aim of treatment is to reach a negative iron balance. This must be achieved before complications due to the chronic iron overload have their effect on the predisposed organs. The extreme uncontrolled increase in iron absorption is treatable by adjuvant measures, albeit with limited success. 

Low-iron nutrition is a fundamental requirement (there is practically no iron-free form of nutrition). However, intake of foodstuffs rich in iron is contraindicated when the iron balance has to be maintained. The iron balance is not influenced to any great extent by this... 

Fe Iron Balance Balance Balance Balance Balance... 

The dosage of deferoxamine should be established on the basis of iron balance and dose-response curves. 

Ampco [Ampco]. TM for a series of alumi-num-iron-copper alloys containing 6-15% aluminum, 1.5-5.25% iron, balance copper. Resistant to... 

Monoferric phytate is the major fraction of iron in wheat bran, and is a highly bioavailable form of dietary iron in contrast to insoluble di- or tetra-ferric phytate. Monoferric phytate equilibrates with the miscible nonheme iron pool of a meal in extrinsic label iron absorption tests. Whole wheat bran depressed absorption by humans of nonheme iron in a meal. Dephytinized wheat bran also inhibited nonheme iron absorption by humans and the inhibition could not be clearly attributed to either the insoluble or soluble fractions of the dephytinized bran. Adult men who consumed 36 g of wheat bran per day had positive iron balances. Iron balance was not increased when dephytinized bran was consumed. The form of ferric phytate must be known to properly explain the effect of phytic acid on iron absorption. The overall meal composition must be considered to evaluate the effect of wheat bran on iron nutrition of humans. 

Based on USDA estimates of per capita consumption of wheat flour, one-third of the adult woman s Recommended Dietary Allowance (RDA) for iron could be obtained if we consumed whole wheat products Q). The iron in wheat, however, is thought to be poorly bioavailable to humans, primarily attributable to the effect of phytate. British investigators found that the iron balance of individuals was lower when they ate largely whole meal bread than when they ate bread made with white flour (2). When the test bread made with white flour contained either sodium or ferric phytate, postprandial serum iron rise was depressed ( ). They theorized that the phytate present in the brown bread formed an insoluble iron salt and rendered the iron unabsorbable. That theory was supported by the work of Moore et al. (4) at Washington University, who tested the response of anemic individuals administered therapuetic doses of ferric... 

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