Effect of excess Fe on cd or Pb absorption by rats

Sullivan, M.F.; Ruemmler, P.S.

doi:10.1080/15287398709531057

Cited by 17 publications

(5 citation statements)

References 31 publications

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“…Possible components are shown in the data presented in Table 3. For example, addition of ferric iron during fasting reduced the percentage retention of the lead dose to that of nonfasted animals (15).…”

Section: Total Food Intakementioning

confidence: 99%

Environmental Lead Toxicity: Nutrition As a Component of Intervention

Mahaffey¹

1990

Environmental Health Perspectives

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The influence of nutritional status on susceptibility to the toxicity of lead is discussed. Emphasis is given to dietary factors of substantial clinical importance. Subtle changes in susceptibility are difficult to evaluate under conditions of overwhelning lead exposure. It is clear that subtle effects of lead exposure on neurobehavioral and cognitive development are a major concern. The role of nutrition is considered to be an adjunct to reduction of environmental lead exposure, which is the primary means of reducing adverse health effects of lead. Nutrition should be evaluated as a component of strategies to address this broad societal issue. Nutrition and Environmental Lead ToxicityPrenatal exposures to lead at concentrations lower than recognized a decade ago adversely affect cognitive, neurobehavioral, and neurophysiological development. The preponderance of results from the published prospective epidemiological studies (1-3) demonstrate that exposure to quantities of lead typically present in the environment have an adverse effect on very early neurobehavioral development.Advances in lead research over the past decade have demonstrated that a very narrow margin of safety exists between typical environmental exposures to lead and the external dose of lead associated with long-term, adverse health effects. Because the margin of safety between exposures and effects is either very narrow or nonexistent, other factors that modify bioldnetics of lead or modify susceptlbility to lead toxicity assume added importance.The role of nutritional status in altering susceptibility to lead toxicity has been recognized during most of this century. The topic has been intensely investigated using a variety of techniques (Table 1), particularly with laboratory investigations. The purpose of the following discussion is to provide an overview of the topic, takdng a closer look at consistencies, inconsistencies, and future directions for use of nutritional intervention as a component of prevention of lead toxicity.The extent of understanding how nutritional factors affect susceptibility to lead vary from nutrient to nutrient. For some nutrient-toxicant interactions, the cellular bases of the interactions are well understood. For example, iron deficiency and lead affect the enzyme kinetics in the heme biosynthetic pathway (4,5). However, when evaluating the whole animal, the effects of multiple organ systems are combined. In the whole animal, the effects of adding quantities of nutrients

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Section: Total Food Intakementioning

confidence: 99%

Environmental Lead Toxicity: Nutrition As a Component of Intervention

Mahaffey¹

1990

Environmental Health Perspectives

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“…Gastrointestinal absorption of Pb is a complex and dynamic process involving dissolution, absorption, and interactions with other dietary components. Iron deficiencies in children have been associated with elevated blood Pb concentrations, and several animal studies have shown that Fe deficiencies increase gastrointestinal absorption of Pb (Barton et al, 1978; Flanagan et al, 1979; Mahaffey and Annest, 1986; Morrison and Quarterman, 1987; Sullivan and Ruemmler, 1987). Dietary deficiencies of Ca, Zn, and P enhance absorption of Pb in humans, rats, mice, and pigs (Heard and Chamberlain, 1982; Hsu et al, 1975; Johnson and Tenuta, 1979; United States Department of Health and Human Services, 1999; Van Barneveld and Van Den Hamer, 1985; World Health Organization, 1996).…”

Section: Resultsmentioning

confidence: 99%

Validation of the In Vitro Gastrointestinal (IVG) Method to Estimate Relative Bioavailable Lead in Contaminated Soils

et al. 2004

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The effect of the dosing vehicle (e.g., dough) on the ability of an in vitro gastrointestinal (IVG) method to predict relative bioavailable Pb associated with soil ingestion was evaluated. Bioaccessible Pb determined by the IVG method was compared with relative bioavailable Pb measured from dosing trials using juvenile swine for 18 contaminated soils ranging from 1270 to 14200 mg Pb kg(-1). Bioaccessible Pb was measured in the IVG gastric extraction (GE) and intestinal extraction (IE) solutions. Mean bioaccessible Pb values were 32.2% for GE without dough, 23.0% for GE with dough, 1.06% for IE without dough, and 0.56% for IE with dough. It is possible that phytic acid associated with the dough addition decreased bioaccessible Pb. In vivo relative bioavailable Pb ranges for different swine tissues were 1 to 87% for blood, 0 to 110% for liver, 1 to 124% for kidney, and 0.04 to 94% for bone. Strong linear relationships between IVG GE Pb with dough (r > 0.76, P < 0.0002), IVG IE Pb with dough (r > 0.56, P < 0.015), and IVG GE Pb without dough (r > 0.81, P < 0.0001) and in vivo bioavailable Pb as estimated with blood, kidney, liver, and bone were found. Inexpensive in vitro methods may be useful in providing an estimate of the variability in relative bioavailable Pb at a single study site. The IVG method can be used to estimate relative bioavailable Pb, As, and Cd in contaminated soil.

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“…It has therefore been suggested oids arising that the correction of iron deficiency hicular ex-among human populations can generally ;, and waste reduce lead toxicity (29). Interestingly, a posures may negative correlation between blood lead [en of metals levels and body burden of iron in human populations has been reported by several authors (30)(31)(32)(33)(34).…”

Section: Poliutantsmentioning

confidence: 90%

Toxic interactions among environmental pollutants: corroborating laboratory observations with human experience.

Krishnan

Brodeur

1994

Environ Health Perspect

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Combined exposures to multiple chemicals may result in interactions leading to a significant increase or decrease in the overall toxicity of the mixture compared to the summation of the toxicity of the components. A large number of chemical interactions have been described in animal studies by administering high doses of chemicals by routes and scenarios often different from anticipated human exposures. Though limited, there is some evidence for the occurrence of several supra-additive (the combined effects are greater than the simple summation of the individual effects) and infra-additive (the combined effects are smaller than the simple summation of the individual effects) chemical interactions in humans. For example, toxicokinetic interactions between several solvents have been found to occur in the workplace, whereas those involving pesticides have been reported less frequently, especially during accidental exposures. Toxic interactions involving nutritionally important metals and metalloids appear to occur more frequently, since several of them have an important role in a variety of physiological and biochemical processes. On the contrary, there is not much evidence to confirm the occurrence of toxic interactions among the commonly encountered inorganic gaseous pollutants in humans. Overall, the majority of chemical interactions observed in animal studies have neither been investigated in humans nor been extrapolated to humans based on appropriate mechanistic considerations. Future research efforts in the chemical interactions arena should address these issues by focusing on the development of mechanistically and biologically based models that allow predictions of the extent of interactions likely to be observed in humans.-Environ Health Perspect 102(Suppl 9): 11-17 (1994)

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Effect of excess Fe on cd or Pb absorption by rats

Cited by 17 publications

References 31 publications

Environmental Lead Toxicity: Nutrition As a Component of Intervention

Environmental Lead Toxicity: Nutrition As a Component of Intervention

Validation of the In Vitro Gastrointestinal (IVG) Method to Estimate Relative Bioavailable Lead in Contaminated Soils

Toxic interactions among environmental pollutants: corroborating laboratory observations with human experience.

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