Effect of magnesium hydroxide on iron absorption following simulated mild iron overdose in human subjects

A Review of Nutrients and Compounds, Which Promote or Inhibit Intestinal Iron Absorption: Making a Platform for Dietary Measures That Can Reduce Iron Uptake in Patients with Genetic Haemochromatosis

Objective

To provide an overview of nutrients and compounds, which influence human intestinal iron absorption, thereby making a platform for elaboration of dietary recommendations that can reduce iron uptake in patients with genetic haemochromatosis.

Design

Review. Setting. A literature search in PubMed and Google Scholar of papers dealing with iron absorption.

Results

The most important promoters of iron absorption in foods are ascorbic acid, lactic acid (produced by fermentation), meat factors in animal meat, the presence of heme iron, and alcohol which stimulate iron uptake by inhibition of hepcidin expression. The most important inhibitors of iron uptake are phytic acid/phytates, polyphenols/tannins, proteins from soya beans, milk, eggs, and calcium. Oxalic acid/oxalate does not seem to influence iron uptake. Turmeric/curcumin may stimulate iron uptake through a decrease in hepcidin expression and inhibit uptake by complex formation with iron, but the net effect has not been clarified.

Conclusions

In haemochromatosis, iron absorption is enhanced due to a decreased expression of hepcidin. Dietary modifications that lower iron intake and decrease iron bioavailability may provide additional measures to reduce iron uptake from the foods. This could stimulate the patients' active cooperation in the treatment of their disorder and reduce the number of phlebotomies.

Sugarcane Molasses - A Potential Dietary Supplement in the Management of Iron Deficiency Anemia

Iron deficiency anemia (IDA) is a serious public health problem that debilitates ∼1.6 billion people globally every year, the majority being pregnant women and children from developing countries. In India, for example, in spite of several operational programs at the national level using iron-folic acid and other allopathic interventions, IDA is still prevalent. Traditional medicines, such as Ayurveda, prescribe herbal formulations containing sugarcane derivatives for the management of pandu, a condition similar to IDA. This article reviews molasses, a sugar industry by-product, as a potential raw material to develop nutraceutical products for IDA. Molasses contains iron and its absorption enhancers, such as sulfur, fructose, and copper, which make it a potential dietary supplement for IDA. More research, product development, and evidence of safety and efficacy of molasses in IDA management can provide a tasty and cost-effective dietary supplement, particularly for children. However, there are challenges, such as competition for raw material from refined sugar manufacturers, quality control, etc., that need to be overcome.

Iron poisoning: a literature-based review of epidemiology, diagnosis, and management

Although seen less frequently than acetaminophen or salicylate poisoning, acute iron poisoning remains a dangerous threat, particularly to pediatric patients. Multiple factors-including legal and manufacturing practices-have changed the landscape of iron poisoning over the decades. Despite these changes, diagnosis and management of iron poisoning have minimally evolved, and the current evidence for iron poisoning is yet based principally on case series, expert consensus, animal studies, and adult volunteer studies. This review article describes in detail the epidemiology of acute iron poisoning as it relates to the pediatric patient, as well as the historical and current array of literature on diagnosis and management.

Effect of deferasirox on iron absorption in a randomized, placebo-controlled, crossover study in a human model of acute supratherapeutic iron ingestion

STUDY OBJECTIVE

In 2005, the Food and Drug Administration approved deferasirox as an oral iron chelating agent for chronic iron overload. To determine usefulness in management of acute iron ingestion, we study the effect of orally administered deferasirox in healthy human adults.

METHODS

A double-blinded, placebo-controlled, randomized, crossover study of 8 healthy human volunteers was conducted. Subjects ingested 5 mg/kg of elemental iron in the form of ferrous sulfate. One hour after iron ingestion, subjects were randomized to receive 20 mg/kg of deferasirox or placebo. Serial iron levels were then obtained. A 2-week washout was used between study arms. The paired t test was used to compare area under time-concentration curves from baseline to both 12- and 24-hour iron levels between groups.

RESULTS

Baseline serum iron levels were similar in the 2 groups. Deferasirox significantly reduced serum iron area under concentration-time curves compared with placebo during both 1 to 12 hours and 1 to 24 hours (12 hour=577 μmol-hour/L and 392 μmol-hour/L, 95% confidence interval for the difference 15.8 to 353.0 μmol-hour/L; 24 hour=808 μmol-hour/L and 598 μmol-hour/L, 95% confidence interval for difference 54.4 to 366.7 μmol-hour/L).

CONCLUSION

Orally administered deferasirox significantly reduced serum iron levels when administered 1 hour after iron ingestion during the 12- and 24-hour periods after acute ingestion of 5 mg/kg of elemental iron in healthy human volunteers. Further study is required to determine optimal dosing, but deferasirox may be an important addition to current therapy for acute iron poisoning.

Minerals and vitamins in bone health: the potential value of dietary enhancement

Nutrition is important to bone health, and a number of minerals and vitamins have been identified as playing a potential role in the prevention of bone diseases, particularly osteoporosis. Despite this, there is currently no consensus on maximum levels to allow in food or as dietary supplements. The benefits of supplementation of populations at risk of osteoporosis with Ca and vitamin D are well established. Prolonged supplementation of Ca and vitamin D in elderly has been shown to prevent bone loss, and in some intervention studies to prevent fragility fractures. Although P is essential to bone health, the average intake is considered to be more than sufficient and supplementation could raise intake to adverse levels. The role of vitamin K in bone health is less well defined, though it may enhance the actions of Ca and vitamin D. Sr administered in pharmacological doses as the ranelate salt was shown to prevent fragility fractures in postmenopausal osteoporosis. However, there is no hard evidence that supplementation with Sr salts would be beneficial in the general population. Mg is a nutrient implicated in bone quality, but the benefit of supplementation via foodstuffs remains to be established. A consensus on dietary supplementation for bone health should balance the risks, for example, exposure of vulnerable populations to values close to maximal tolerated doses, against evidence for benefits from randomised clinical trials, such as those for Ca and vitamin D. Feedback from community studies should direct further investigations and help formulate a consensus on dietary supplementation for bone health.

Effect of Oral Calcium Disodium EDTA on Iron Absorption in a Human Model of Iron Overdose

OBJECTIVE

Anecdotal case reports and animal models have suggested that the administration of CaNa2EDTA (EDTA) may be effective in reducing the absorption of iron after an oral iron overdose. We designed this study to determine the effect of orally administrated EDTA with or without activated charcoal (AC) on iron absorption after a mild iron ingestion in healthy human volunteers.

METHODS

A randomized, crossover study was conducted in eight healthy human volunteers. All subjects ingested 5 mg/kg of elemental iron in the form of ferrous sulfate. One hour post ingestion, subjects were randomized to receive 35 mg/kg EDTA, EDTA plus 50 grams of AC, or water. Serial iron levels were obtained at baseline and every hour for the first 6 hours, then at 8, 12, and 24 hours. A 2-week washout was used between study arms. The Kruskal-Wallis test was used for the following comparisons between treatment groups: baseline serum iron levels, area under time-concentration curves (AUCs) from baseline to 12 hours and baseline to 24 hours, and peak iron levels.

RESULTS

Baseline serum iron levels did not differ among the three treatment groups (p = 0.844). AUCs were not different among groups (p = 0.746 for 12 hr, p = 0.925 for 24 hr). AUC medians (with 95% binomial confidence bounds) for control, EDTA, EDTA + AC groups, respectively, for 12 hr were: 2813 (2298, 3561), 2570 (1669, 3476), and 2654 (2125, 3600); and for 24 hr were: 4083 (3488,5314), 4139 (2666, 5547), and 4274 (3336, 5577). Peak serum iron levels did not differ among treatment groups (p = 0.481). Peak iron level medians in microg/dL (with 95% binomial confidence bounds) were for control: 329 (253, 382), for EDTA: 271 (184, 375), and for EDTA + AC: 285 (229, 352).

CONCLUSION

Orally administered EDTA did not significantly reduce iron absorption when administered 1 hour post iron ingestion during the 12 or 24-hour period following the ingestion of 5 mg/kg of elemental iron in healthy human volunteers.

Iron Ingestion: an Evidence-Based Consensus Guideline for Out-of-Hospital Management

From 1983 to 1991, iron caused over 30% of the deaths from accidental ingestion of drug products by children. An evidence-based expert consensus process was used to create this guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the primary author. The entire panel discussed and refined the guideline before its distribution to secondary reviewers for comment. The panel then made changes in response to comments received. The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial management of patients with suspected ingestions of iron by 1) describing the manner in which an ingestion of iron might be managed, 2) identifying the key decision elements in managing cases of iron ingestion, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline applies to ingestion of iron alone and is based on an assessment of current scientific and clinical information. The expert consensus panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all of the circumstances involved. The panel's recommendations follow; the grade of recommendation is in parentheses. 1) Patients with stated or suspected self-harm or who are victims of malicious administration of an iron product should be referred to an acute care medical facility immediately. This activity should be guided by local poison center procedures. In general, this should occur regardless of the amount ingested (Grade D). 2) Pediatric or adult patients with a known ingestion of 40 mg/kg or greater of elemental iron in the form of adult ferrous salt formulations or who have severe or persistent symptoms related to iron ingestion should be referred to a healthcare facility for medical evaluation. Patients who have ingested less than 40 mg/kg of elemental iron and who are having mild symptoms can be observed at home. Mild symptoms such as vomiting and diarrhea occur frequently. These mild symptoms should not necessarily prompt referral to a healthcare facility. Patients with more serious symptoms, such as persistent vomiting and diarrhea, alterations in level of consciousness, hematemesis, and bloody diarrhea require referral. The same dose threshold should be used for pregnant women, however, when calculating the mg/kg dose ingested, the pre-pregnancy weight of the woman should be used (Grade C). 3) Patients with ingestions of children's chewable vitamins plus iron should be observed at home with appropriate follow-up. The presence of diarrhea should not be the sole indicator for referral as these products are often sweetened with sorbitol. Children may need referral for the management of dehydration if vomiting or diarrhea is severe or prolonged (Grade C). 4) Patients with unintentional ingestions of carbonyl iron or polysaccharide-iron complex formulations should be observed at home with appropriate follow-up (Grade C). 5) Ipecac syrup, activated charcoal, cathartics, or oral complexing agents, such as bicarbonate or phosphate solutions, should not be used in the out-of-hospital management of iron ingestions (Grade C). 6) Asymptomatic patients are unlikely to develop symptoms if the interval between ingestion and the call to the poison center is greater than 6 hours. These patients should not need referral or prolonged observation. Depending on the specific circumstances, follow-up calls might be indicated (Grade C).

The Changing Indications of Gastrointestinal Decontamination in Poisonings

Gastrointestinal (GI) decontamination is commonly used in the treatment of the poisoned patient. Although the practice is widely accepted, the science behind the recommendations is limited. This article describes commonly used techniques for GI decontamination and critically reviews the studies evaluating these treatments.

Gastrointestinal decontamination

Overall, no conclusive data support the use of gastric decontamination in the routine management of the poisoned patient. Studies of asymptomatic patients suggest that no treatment is required, and, given the complications that have been reported, this may be a reasonable approach to' most patients. Even in symptomatic patients, the only demonstrable benefit was found in a post-hoc subgroup analysis and involved an outcome of questionable clinical importance. Given these data, it would be easy to conclude that GI decontamination has no role in the management of the poisoned patient. This conclusion is valid when considering poisoned patients as a group, but all poisoned patients are not the same. Patients with trivial ingestion do well without treatment, and their greatest risk is an iatrogenic complication. Even patients with more serious ingestions usually have good outcomes with supportive care alone. It is no longer sufficient to justify GL or forced administration of AC with the supposition that "the patient could have taken something bad." However,there are some overdoses where limiting the systemic absorption of the poison may limit the toxic effects and prevent serious toxicity. After careful consideration of the risks, GI decontamination should be targeted at patients who, in the opinion of the treating physician, have a potentially life-threatening exposure.

Efficacy of the cation exchange resin, sodium polystyrene sulfonate, to decrease iron absorption

BACKGROUND

Iron is not bound by charcoal; therefore, a method of binding iron in the gastrointestinal tract to prevent absorption in iron overdose is needed. This study investigated the efficacy and safety of sodium polystyrene sulfonate to prevent absorption of iron in human volunteers.

METHODS

Six adult volunteers completed this prospective crossover trial. Following an oral dose of elemental iron 10 mg/kg, each subject received sodium polystyrene sulfonate 30 g or water as control. Baseline and serial serum iron samples were drawn to determine pharmacokinetic parameters.

RESULTS

A trend toward increased time to peak following sodium polystyrene sulfonate compared to the control arm (5.7 vs 3.6 hours) was observed but was not statistically significant (p = 0.517). A trend toward smaller area-under-the-curve for the sodium polystyrene sulfonate was evident but was not statistically significant (p = 0.77). Iron concentration increased on average 298 mcg/dL and 370 mcg/dL above baseline in the treatment and control arms (p = 0.44). Sodium polystyrene sulfonate is not an effective method of decontamination for iron overdose.