Iron, oxidative stress, and disease risk

Elements in trace amount with a significant role in human physiology: a tumor pathophysiological and diagnostic aspects

Cancer has a devastating impact globally regardless of gender, age, and community, which continues its severity to the population due to the lack of efficient strategy for the cancer diagnosis and treatment. According to the World Health Organisation report, one out of six people dies due to this deadly cancer and we need effective strategies to regulate it. In this context, trace element has a very hidden and unexplored role and require more attention from investigators. The variation in concentration of trace elements was observed during comparative studies on a cancer patient and a healthy person making them an effective target for cancer regulation. The percentage of trace elements present in the human body depends on environmental exposure, food habits, and habitats and could be instrumental in the early diagnosis of cancer. In this review, we have conducted inclusive analytics on trace elements associated with the various types of cancers and explored the several methods involved in their analysis. Further, intricacies in the correlation of trace elements with prominent cancers like prostate cancer, breast cancer, and leukaemia are represented in this review. This comprehensive information on trace elements proposes their role during cancer and as biomarkers in cancer diagnosis.

Effect of Ascorbic Acid on Oxidative Stress Parameters of Fruit Fly in the Presence of Fe (II)

Excessive iron intake causes lipid peroxidation and increases oxidative stress. Ascorbic acid is a natural compound with antioxidant and therapeutic properties. In this study, the effect of AA on oxidative stress parameters in fruit flies in the presence of iron was investigated. Third instar larvae were exposed to Fe and/or AA. Antioxidant enzyme activities, MDA, and GSH levels were determined in adult heads developing from the larvae. The mRNA levels of the enzymes were also analyzed. Iron treatment caused inhibition of SOD, CAT, and GPx enzymes, and only a decrease in the mRNA level of CAT. However, AA treatment together with iron prevented the inhibition. In addition, iron treatment increased the MDA level and decreased the GSH level. AA treatment together with iron ameliorated the changes in MDA and GSH levels. The results showed that AA can interfere with the iron-induced changes. Considering the potential of AA to ameliorate iron-induced changes, further studies are needed to elucidate the effect of AA on different mechanisms.

Exercise Performance Upregulatory Effect of R-α-Lipoic Acid with γ-Cyclodextrin

α-Lipoic acid (ALA) is a vitamin-like substance that is an indispensable supporting factor for a large number of enzymes. Due to its optical activity, ALA has optical isomers RALA and SALA. The major role of RALA is in energy metabolism. However, RALA cannot be used as a pharmaceutical or nutraceutical because it is sensitive to heat and acid conditions. Previous studies have shown that RALA complexed with γ-cyclodextrin (CD) has a higher antioxidant capacity than that of free RALA. The antioxidant enzyme system protects against intense exercise-induced oxidative damage and is related to the physical status of athletes. The aim of this study was to examine the effect of CD/RALA complex supplementation on antioxidant activity and performance during high-intensity exercise. Twenty-four male C3H/HeSlc mice were divided into four groups (n = 6): swimming+distilled water administration (C), swimming+CD/RALA supplementation (CD/RALA), swimming+RALA suplementation (RALA), and swimming+CD supplementation (CD). Blood ammonia elevation due to exercise stress was repressed by CD/RALA supplementation. The oxidative stress in the kidney increased after exercise and was reduced by CD/RALA supplementation. Our findings suggest that CD/RALA supplementation may be useful for improving the exercise performance in athletes.

Dietary iron to total energy intake ratio and type 2 diabetes incidence in a longitudinal 12-year analysis of the Korean Genome and Epidemiology Cohort Study

PURPOSE

Recent study found iron consumption has been associated with an increased risk of type 2 diabetes (T2DM). Even though, high iron intake is correlated with total caloric intake, most studies have evaluated the individual effect of iron and total caloric intake. The aim of this study was to investigate the effect of iron intake, in conjunction with total energy intake, on developing T2DM. We also investigated the interactions between dietary iron and energy ratios (IERs) and iron-related single nucleotide polymorphisms (SNPs) in the development of T2DM.

METHODS

The study was carried out in Ansan and Ansung, Korea, between March 2001 and December 2014. A total of 6413 participants (3073 men and 3340 women), aged 40-69 years, were enrolled in this study. The mean follow-up period was 8.4 years. The study population was divided into quartiles based on IERs with cut-off points at 4.54, 5.41, and 6.29. The odds ratios (ORs) for new-onset T2DM were calculated across each quartile of IERs and a random forest model was constructed using the default settings to predict new-onset T2DM. To confirm the interaction among IERs, SNPs, and the incidence of T2DM, we measured the predictive power of new-onset T2DM using IER and six SNPs in genes related to iron metabolism [rs855791 (TPMRSS6), rs38116479 (TF), rs1799852 (TF), rs2280673, rs1799945 (HFT), rs180562 (HFE)].

RESULTS

The prevalence of T2DM was 762 (11.8%). IERs showed a positive association with T2DM. The ORs were 1.30 (95% CI 1.02-1.67), 1.20 (95% CI 0.94-1.56), and 1.43 (95% CI 1.11-1.86) across the IER quartiles after adjusting for non-dietary and dietary metabolic risk factors. When the IER was 1.89-fold higher than the reference group, the risk of developing T2DM increased by 43% (OR 1.43; 95% CI 1.11-1.86).

CONCLUSION

A higher IER was positively associated with developing T2DM independent of dietary or non-dietary risk factors. We also found the possible interactions between the identified SNPs and iron intake in relations to T2DM.

Iron deposition in autopsied liver specimens from older patients receiving intravenous iron infusion

Background

Vitamins and minerals are routinely administered by total parenteral nutrition (TPN). However, in Japan, adjustments in iron dosage are difficult because blended mineral preparations are often used. It is therefore unclear whether the iron content is appropriate in cases of long-term TPN. The aim of the study was to assess the influence of iron administration by long-term TPN on iron deposition in post-mortem liver samples isolated from older deceased patients.

Methods

Liver tissues were collected from post-mortem autopsies of 187 patients over a period of 15 years. Samples were stained with Prussian blue and histologically evaluated from Grade 0–V by at least three different observers. Specimens with positive and negative iron staining were compared, and positive samples were grouped according to the level and distribution of the staining. Post-mortem blood obtained from the subclavian vein during autopsy was also analysed. Samples were collected for the measurement of unsaturated serum iron, serum iron, albumin, prealbumin, hepcidin, and IL-6 concentrations.

Results

Iron accumulation in the liver was significantly higher in male patients (p = 0.005) with a history of surgery (p = 0.044) or central vein administration of iron (p<0.001). Additionally, the duration of TPN in the iron-positive group was significantly longer than in the iron-negative group (p = 0.038). Serum analysis revealed that unsaturated serum iron was significantly higher in the iron-negative group and that ferritin and serum iron were significantly higher in the iron-positive group. No other statistically significant differences were observed between the two groups.

Conclusions

Chronic intravenous administration of iron was associated with iron deposition in the liver, even when given the minimum recommended dosage. In long-term TPN patients, the iron dose should therefore be carefully considered.

LRRC19-A Bridge between Selenium Adjuvant Therapy and Renal Clear Cell Carcinoma: A Study Based on Datamining

Kidney renal clear cell carcinoma (KIRC) is the most common and fatal subtype of renal cancer. Antagonistic associations between selenium and cancer have been reported in previous studies. Selenium compounds, as anti-cancer agents, have been reported and approved for clinical trials. The main active form of selenium in selenoproteins is selenocysteine (Sec). The process of Sec biosynthesis and incorporation into selenoproteins plays a significant role in biological processes, including anti-carcinogenesis. However, a comprehensive selenoprotein mRNA analysis in KIRC remains absent. In the present study, we examined all 25 selenoproteins and identified key selenoproteins, glutathione peroxidase 3 (GPX3) and type 1 iodothyronine deiodinase (DIO1), with the associated prognostic biomarker leucine-rich repeat containing 19 (LRRC19) in clear cell renal cell carcinoma cases from The Cancer Genome Atlas (TCGA) database. We performed validations for the key gene expression levels by two individual clear cell renal cell carcinoma cohorts, GSE781 and GSE6344, datasets from the Gene Expression Omnibus (GEO) database. Multivariate survival analysis demonstrated that low expression of LRRC19 was an independent risk factor for OS. Gene set enrichment analysis (GSEA) identified tyrosine metabolism, metabolic pathways, peroxisome, and fatty acid degradation as differentially enriched with the high LRRC19 expression in KIRC cases, which are involved in selenium therapy of clear cell renal cell carcinoma. In conclusion, low expression of LRRC19 was identified as an independent risk factor, which will advance our understanding concerning the selenium adjuvant therapy of clear cell renal cell carcinoma.

Serum Levels of Selenium, Zinc, Copper, Manganese, and Iron in Prostate Cancer Patients

Backgrounds

Variations of trace element contents may be associated with several diseases including metabolic disorders, cellular growth disturbance, mutation and tumorigenesis. Prostate cancer is the second most common male cancer worldwide and stand fifth most common male cancer in Saudi Arabia.

Objective

In the present study, Serum levels of selenium, zinc, copper, manganese, and iron were measured in patients with BPH and prostate cancer aiming to explore the association between these elements and prostate cancer.

Patients and Methods

The study included 40 newly diagnosed prostate cancer patients, 22 patients with BPH and 30 healthy male subjects. All participant groups had similar socio-economic levels. Fasting blood samples were collected from all subjects and before any intervention for the patients. Serum PSA concentrations were analyzed by ELIZA and trace elements Se, Zn, Cu, Mn and Fe were measured by ICP-MS.

Results

Serum Se, Zn, and Mn levels of prostate cancer patients were significantly decreased compared to control groups. The levels of serum Cu and Fe were significantly higher in prostate cancer patients than in control groups.

Conclusion

In the present study, an association was noticed between serum trace elements disturbance and prostate cancer. The decreased levels of Se, Zn, and Mn, and increased Cu and Fe levels may play significant roles in the initiation of prostate cancer. However, future prospective studies on the causes of trace elements alteration in prostate cancer patients are needed as well as to illustrate the relation between different prostate cancer stages and trace elements concentrations.

Effectiveness of Grounded Sleeping on Recovery After Intensive Eccentric Muscle Loading

Purpose: We set out to investigate the effectiveness of grounded sleeping on the time course of recovery with respect to muscle soreness and athletic performance after intensive eccentric muscle loading. Methods: Twenty-two healthy participants were recruited for this study and randomly assigned to an experimental group (GRD, grounded sleeping, n = 12) or control group (UGD, sham-grounded sleeping, n = 10) to evaluate the effects of 10 days recovery with GRD vs. UGD following a single intensive downhill treadmill intervention in a triple-blinded (participant, tester, and data analyst) manner. To operationalize recovery a test battery was performed at baseline and on days 1, 2, 3, 5, 7, and 10 post-intervention: (1) perception of muscle soreness (VAS), (2) creatine kinase blood levels (CK), (3) maximum voluntary isometric contraction (MVIC) for both legs, (4) counter movement jump (CMJ) and drop jump (DJ) performance. Furthermore, in four participants blood was sampled for detailed analysis of complete blood counts and serum-derived inflammation markers. Results: The downhill treadmill running intervention led to distinct changes in all measured parameters related to fatigue. These changes were detectable already 5-min post intervention and were not fully recovered 10 days post intervention. GRD led to less pronounced decrease in performance (CMJ, MVIC) and less increase with respect to CK compared with UGD (all P < 0.05). Detailed blood samples demonstrated that grounded sleeping modulates the recovery process by (a) keeping a constant hemoconcentration, as represented by the number of erythrocytes, and the hemoglobin/hematocrit values; and (b) by the reduction of muscle damage-associated inflammation markers such as, IP-10, MIP-1α, and sP-Selectin. Conclusion: The downhill running protocol is a feasible methodology to produce long term muscle soreness and muscular fatigue. GRD was shown to result in faster recovery and/or less pronounced markers of muscle damage and inflammation. GRD might be seen as a simple methodology to enhance acute and long-term recovery after intensive eccentric exercises.

The Relationship between Serum Ferritin Levels and Insulin Resistance in Pre- and Postmenopausal Korean Women: KNHANES 2007-2010

Background

Serum ferritin levels increase in postmenopausal women, and they are reported to be linked to major health problems. Here, we investigated the association between serum ferritin levels and insulin resistance (IR) in postmenopausal women.

Methods

A total of 6632 healthy Korean women (4357 premenopausal and 2275 postmenopausal) who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) in 2007–2010 were enrolled in the study. Serum ferritin values were divided into six groups for the premenopausal and postmenopausal groups. IR and obesity indices were evaluated according to the six serum ferritin groups. Statistical analysis was carried out using SAS software, version 9.2 (SAS Institute Inc., Cary, NC, USA).

Results

The association between the IR indices and ferritin groups had a higher level of statistical significance in the postmenopausal group than in the premenopausal group. In addition, for the postmenopausal group, the estimates increased significantly in the sixth ferritin group compared to those in the first ferritin group. However, the association between the obesity indices and ferritin levels was not significantly different between the premenopausal and postmenopausal groups.

Conclusion

Elevated serum ferritin levels were associated with an increased risk of insulin resistance in postmenopausal women.

The impact of partial hepatectomy on oxidative state in the liver remnant - An in vivo swine model

Background

Previous studies on oxidative state after partial hepatectomy (PHx) report conflicting data on levels of glutathione (GSH) and are mainly presented in rodent models by methodology less sensitive than the present technologies. The current swine model presents GSH levels and the following genetic response post-PHx, utilizing an analytical platform more sensitive and precise than earlier available.

Method

Twelve pigs were randomized to a PHx- and a control group (n=6 in each). The PHx group had a 60% hepatectomy. Serial in vivo liver biopsies during 12 h of anaesthesia post-PHx were analyzed for GSH by liquid chromatography mass spectrometry (LC-MS/MS). Transcriptional alterations of genes (GS, GCLM, GCLC, GR, HGF, NFE2L2, TGFβ1) regulating GSH synthesis were measured by real-time PCR.

Results

No difference was detected between the GSH levels in the PHx- and the control group during the experiment (P=0.247). Still, decreased gene expression of GS (P=0.026) and NFE2L2 (P=0.014) the first nine hours, and a decrease of TGFβ1 (P=0.029) the first seven hours post-PHx was seen in the liver remnant.

Conclusion

The results show that the liver has an extended capacity to maintain GSH homeostasis during major stress and parenchymal loss, even at the early onset of such trauma. This observation was not explained by increased expression of key genes in GSH pathways. Consequently, the results indicate an inherent compensatory capacity to maintain GSH homeostasis in the reduced organ.

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The levels of Glutathione are maintained after a 60% hepatectomy in a swine study.

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Oxidative state is analyzed after partial hepatectomy using mass spectrometry.

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Glutathione is analyzed after partial hepatectomy using mass spectrometry.

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The liver has extended capacity to remain GSH homeostasis after partial hepatectomy.

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Glutathione in liver tissue is analyzed after partial hepatectomy in a swine model.

Serum levels of trace elements in patients with prostate cancer

BACKGROUND

Trace elements are major components of biological structures; however, excessive levels of these elements can be toxic.

MATERIALS AND METHODS

In the present study, serum levels of trace elements were measured in 30 patients with newly diagnosed as prostate cancer and 32 healthy volunteer by using furnace atomic absorption spectrophotometry.

RESULTS

It was found that there was an increase in serum levels of Co, Cu, Mg and Pb (p<0.05), whereas a decrease in serum levels of Fe, Mn, and Zn levels in patients with prostate cancer (p<0.05).

CONCLUSIONS

These changes may be important in the pathogenesis of prostate cancers; however, further prospective studies are needed to identify relationships between prostate cancer and trace elements.

Using oxidant susceptibility of thiol stabilized nanoparticles to develop an inflammation triggered drug release system

Ultrasmall thiol passivated ZnS NPs are prepared using a newly developed synthetic protocol. Exposure to hydroxyl radicals results in oxidation of the thiol groups, thus destabilizing the ZnS nanolids to open drug encompassing pores for attaining an inflammation responsive drug delivery system.

Genetic determinants for body iron store and type 2 diabetes risk in US men and women

Background

High body iron store has been associated with an increased risk of type 2 diabetes (T2D); it remains unknown whether the genetic variants related to body iron status affect T2D risk. We aimed at comprehensively investigating the associations between the genetic variants related to body iron status and the T2D risk.

Methodology/Principal Findings

Six common SNPs related to body iron status from recent genome-wide association (GWA) studies were determined in the Nurses’ Health Study (NHS; 1,467 diabetic cases and 1,754 controls) and the Health Professionals Follow-up Study (HPFS; 1,124, diabetic cases and 1,298 controls). Plasma levels of ferritin, soluble transferrin receptor (sTfR), and transferrin were measured in NHS. Significant associations were observed for loci in TPMRSS6 with sTfR (P = 3.47×10⁻⁶), TF with transferrin (P = 0.0002 to 1.72×10⁻¹⁰); and HFE with ferritin (P = 0.017 to 1.6×10⁻⁸), sTfR (P = 0.007 to 7.9×10⁻⁶), and transferrin (P = 0.006 to 0.0007). The six SNPs together explained 5.7%, 2.7%, and 13.3% of the variation in plasma levels of ferritin, sTfR, and transferrin. After adjustment for the conventional risk factors, the T allele of SNP rs855791 in the TPMRSS6 gene was significantly associated with a 19% decreased risk of T2D (OR = 0.81; 95% CI = 0.66–0.98; P = 0.03) in men. Multiple tests attenuated this significant association to null. No associations were observed in women. SNPs at HFE and TF were not associated with diabetes risk in either sex. Dietary iron intake did not modify the associations of the newly identified loci with diabetes risk.

Conclusions/Significance

The newly identified iron-related SNP rs855791 in TPMRSS6 was nominally associated with a decreased risk of T2D in men but not in women. The apparent differences by gender warrant further study.

Reduction of mitoferrin results in abnormal development and extended lifespan in Caenorhabditis elegans

Iron is essential for organisms. It is mainly utilized in mitochondria for biosynthesis of iron-sulfur clusters, hemes and other cofactors. Mitoferrin 1 and mitoferrin 2, two homologues proteins belonging to the mitochondrial solute carrier family, are required for iron delivery into mitochondria. Mitoferrin 1 is highly expressed in developing erythrocytes which consume a large amount of iron during hemoglobinization. Mitoferrin 2 is ubiquitously expressed, whose functions are less known. Zebrafish with mitoferrin 1 mutation show profound hypochromic anaemia and erythroid maturation arrests, and yeast with defects in MRS3/4, the counterparts of mitoferrin 1/2, has low mitochondrial iron levels and grows poorly by iron depletion. Mitoferrin 1 expression is up-regulated in yeast and mouse models of Fiedreich's ataxia disease and in human cell culture models of Parkinson disease, suggesting its involvement in the pathogenesis of diseases with mitochondrial iron accumulation. In this study we found that reduced mitoferrin levels in C. elegans by RNAi treatment causes pleiotropic phenotypes such as small body size, reduced fecundity, slow movement and increased sensitivity to paraquat. Despite these abnormities, lifespan was increased by 50% to 80% in N2 wild type strain, and in further studies using the RNAi sensitive strain eri-1, more than doubled lifespan was observed. The pathways or mechanisms responsible for the lifespan extension and other phenotypes of mitoferrin RNAi worms are worth further study, which may contribute to our understanding of aging mechanisms and the pathogenesis of iron disorder related diseases.

An association between polymorphism of the heme oxygenase-1 and -2 genes and age-related macular degeneration

Iron may be implicated in the generation of oxidative stress by the catalyzing the Haber–Weiss or Fenton reaction. On the other hand, oxidative stress has been implicated in the pathogenesis of age-related macular degeneration (AMD) and heme oxygenase-1 (HO-1), encoded by the HMOX1 gene and heme oxygenase-2 (HO-2), encoded by the HMOX2 gene are important markers of iron-related oxidative stress and its consequences. Therefore, variability of the HMOX1 and HMOX2 genes might be implicated in the pathogenesis of AMD through the modulation of the cellular reaction to oxidative stress. In the present work, we investigated the association between AMD and a G → C transversion at the 19 position in the HMOX1 gene (the 19G>C-HMOX1 polymorphism, rs2071747) and a A → G transition at the −42 + 1444 position in the HMOX2 gene (the −42 + 1444A>G-HMOX2 polymorphism, rs2270363) and its modulation by some environmental factors. 279 patients with AMD and 105 controls were recruited in this study and the polymorphisms were typed by restriction fragment length polymorphism and allele-specific polymerase chain reaction (PCR). We observed an association between the occurrence of dry AMD and the G/A genotype of the −42 + 1444A>G-HMOX2 polymorphism (odds ratio (OR) 2.72), whereas the G/G genotype reduced the risk of dry AMD (OR 0.41). The G/C genotype and the C allele of the 19 G>C-HMOX1 polymorphism and the G/G genotype and the G allele of the −42 + 1444A>G-HMOX2 polymorphism were associated with progression of AMD from dry to wet form (OR 4.83, 5.20, 2.55, 1.69, respectively). On the other hand, the G/G genotype and the G allele of the 19 G>C-HMOX1 polymorphism and the A/G genotype and the A allele of the −42 + 1444A>G-HMOX2 polymorphism protected against AMD progression (OR 0.19, 0.19, 0.34, 0.59, respectively). Therefore, the 19G>C-HMOX1 and the −42 + 1444A>G-HMOX2 polymorphisms may be associated with the occurrence and progression of AMD.

Iron status in elite young athletes: gender-dependent influences of diet and exercise

Iron depletion seems to occur more frequently among athletes than in the general population and may affect performance capacity. Only little information is available about the prevalence of iron status abnormalities in young elite athletes and whether iron depletion is associated with gender, sport, age or nutrition- and exercise-related factors in this group. Hence, diet, exercise and haematological data from 193 elite athletes (96 males, 97 females; 16.2 ± 2.7 years) from 24 different sports were analyzed retrospectively. Most female athletes failed to meet the recommended daily allowance for iron, even though dietary iron density was higher than in males (5.75 ± 0.78 vs. 6.17 ± 0.98 mg/1,000 kcal; P = 0.001). Iron depletion (serum ferritin < 35 μg/L) occurred in 31% of male and 57% of female athletes (P < 0.001). Low haemoglobin (males: <13 g/dL; females: <12 g/dL) and haematocrit (males: <40%; females: <36%) values were equally prevalent in both genders [haemoglobin: 7.3% (males), 6.2% (females); haematocrit: 13.5% (males); 15.5% (females)]. In females, reduced ferritin levels were associated with a lower dietary iron density (5.9 ± 0.8 vs. 6.6 ± 1.1 mg/1,000 kcal; P = 0.002). Males with iron depletion had a significantly higher estimated energy expenditure (48.7 ± 7.0 vs. 44.4 ± 7.6 kcal/kg/day; P = 0.009).

Phytic Acid Protects against 6-Hydroxydopamine-Induced Dopaminergic Neuron Apoptosis in Normal and Iron Excess Conditions in a Cell Culture Model

Iron may play an important role in Parkinson's disease (PD) since it can induce oxidative stress-dependent neurodegeneration. The objective of this study was to determine whether the iron chelator, phytic acid (IP6) can protect against 6-hydroxydopamine- (6-OHDA-) induced apoptosis in immortalized rat mesencephalic dopaminergic cells under normal and iron-excess conditions. Caspase-3 activity was increased about 6-fold after 6-OHDA treatment (compared to control; P < .001) and 30 μmol/L IP6 pretreatment decreased it by 38% (P < .05). Similarly, a 63% protection (P < .001) against 6-OHDA induced DNA fragmentation was observed with IP6 pretreatment. Under iron-excess condition, a 6-fold increase in caspase-3 activity (P < .001) and a 42% increase in DNA fragmentation (P < .05) with 6-OHDA treatment were decreased by 41% (P < .01) and 27% (P < .05), respectively, with 30 μmol/L IP6. Together, our data suggest that IP6 protects against 6-OHDA-induced cell apoptosis in both normal and iron-excess conditions, and IP6 may offer neuroprotection in PD.

Mineral intake and lung cancer risk in the NIH-American Association of Retired Persons Diet and Health study

BACKGROUND

Using data from a case-control study, we previously reported that low dietary intakes of magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), but not selenium (Se) and calcium (Ca), were associated with increased lung cancer risk. Due to dietary recall bias in case-control studies, our objective was to assess whether these findings hold in a prospective cohort study.

METHODS

We analyzed data from the NIH-American Association of Retired Persons Diet and Health study of 482,875 subjects (288,257 men and 194,618 women) who were cancer-free and completed a food frequency questionnaire at enrollment between 1995 and 2003. Cox proportional hazards models were computed to estimate the relative risk adjusted for potential confounders.

RESULTS

During a mean follow-up of 7 years, 7,052 lung cancer cases were identified. For all subjects, we observed no significant associations between total (diet + supplement) Ca, Mg, Fe, Cu, Se, and Zn intakes and lung cancer risk. Total Ca intake was protective (P trend < 0.05) for current smokers and subjects with adenocarcinomas. Total Mg intake increased risk (P trend < 0.05) in men and current smokers. Total Fe intake was inversely associated with risk in women (P trend < 0.01). For dietary minerals, Mg increased risk (P trend < 0.05) in all subjects, among men and current smokers. Increased dietary Ca intake reduced risk in women (P trend = 0.05). Dietary Fe decreased risk in all subjects and among women (P trend < 0.05). Mineral intake from supplements did not affect lung cancer risk.

CONCLUSIONS

Dietary minerals are risk factors for lung cancer.

IMPACT

Dietary mineral consumption may influence lung cancer risk, but the associations differ by type of mineral and population subgroups.

A prospective study of magnesium and iron intake and pancreatic cancer in men

Many studies have investigated the relation between magnesium and iron intake and diabetes and, separately, between diabetes and pancreatic cancer. However, no known study has examined the direct association of magnesium and iron intake with pancreatic cancer risk. The authors obtained magnesium and iron intake data using food frequency questionnaires from the US male Health Professionals Follow-up Study, which began in 1986. During 851,476 person-years and 20 years of follow-up, 300 pancreatic cancer cases were documented. Cox proportional hazards models were used to estimate relative risks, adjusting for age, smoking, and body mass index. No associations were observed between magnesium or iron intake and pancreatic cancer (highest vs. lowest quintile: relative risk (RR) = 0.94, 95% confidence interval (CI): 0.66, 1.32 and RR = 0.93, 95% CI: 0.65, 1.34, respectively). Similarly, iron or magnesium supplement use was not related to pancreatic cancer. A statistically significant inverse relation was noted between magnesium and pancreatic cancer for subjects with a body mass index of > or =25 kg/m(2) (RR = 0.67, 95% CI: 0.46, 0.99; P-trend = 0.04). Although, overall, no relation between magnesium or iron intake and pancreatic cancer was observed in this cohort of men, an inverse association with magnesium was suggested among overweight individuals, which should be examined in other studies.

Association of oxidative stress, iron, and centralized fat mass in healthy postmenopausal women

OBJECTIVE

Centralized adiposity, insulin resistance, excess iron, and elevated oxidative stress place postmenopausal women at risk for atherosclerotic cardiovascular disease (CVD). The objective of this study was to determine the relationship among excess iron, oxidative stress, and centralized fat mass in healthy postmenopausal women.

METHODS

The parent project recruited healthy women for a randomized, double-blind, clinical trial designed to examine the effect of soy isoflavones on bone. At baseline (n = 122), we measured three antioxidant enzymes, iron status indices (serum ferritin among others), oxidative stress indices (oxidized low-density lipoprotein [oxLDL], urinary isoprostanes [PGF(2alpha)], protein carbonyls, DNA damage), and waist, hip, and thigh fat mass using dual-energy x-ray absorptiometry (DXA). We calculated insulin resistance using the homeostasis model assessment (HOMA). Multiple regression analysis was used to determine the CVD risk factors that contributed to oxidative stress and centralized fat mass (waist + hip/thigh = AndGynFM ratio).

RESULTS

Almost 14% (p < 0.0005) of the variability in oxLDL was accounted for by AndGynFM ratio (6.1%, p < 0.0005), age (4.0%, p = 0.012), and serum iron (2.8%, p = 0.053). Similarly, 16% (p < 0.0001) of the variability in PGF(2alpha) was accounted for by the AndGynFM ratio (4.8%, p = 0.011), HOMA (3.9%, p = 0.021), and serum iron (2.7%, p = 0.054). We accounted for 33% (p

CONCLUSIONS

Our study suggests that reducing centralized fat mass and maintaining a favorable lipid profile, antioxidant status, and iron status all may be important in protecting postmenopausal women from atherosclerotic CVD.

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Key Words Collapse

MESH Headings

• Aged
• Biomarkers/blood
• Body Fat Distribution/adverse effects
• Body Mass Index
• Bone Density/drug effects
• Bone and Bones/drug effects
• Coronary Artery Disease/blood
• Coronary Artery Disease/etiology
• Coronary Artery Disease/prevention & control
• Double-Blind Method
• Female
• Ferritins/blood
• Folic Acid/blood
• Humans
• Iron/metabolism
• Middle Aged
• Oxidative Stress/drug effects
• Postmenopause/blood
• Reference Values
• Soybean Proteins/administration & dosage
• Soybean Proteins/pharmacology
• Waist-Hip Ratio

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Grants

• R01 AR046922-01A2 NIAMS NIH HHS
• R01 AR046922 A2 NIAMS NIH HHS
• P01 ES012020 NIEHS NIH HHS
• 95P50AT004155 NCCIH NIH HHS

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Affiliation(s)

Betsy L. Crist Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
D. Lee Alekel Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa Nutrition and Wellness Research Center, Iowa State University, Ames, Iowa
Laura M. Ritland Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
Laura N. Hanson Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
Ulrike Genschel Department of Statistics, Iowa State University, Ames, Iowa
Manju B. Reddy Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa

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Reactive oxygen species: role in the development of cancer and various chronic conditions

Oxygen derived species such as superoxide radical, hydrogen peroxide, singlet oxygen and hydroxyl radical are well known to be cytotoxic and have been implicated in the etiology of a wide array of human diseases, including cancer. Various carcinogens may also partly exert their effect by generating reactive oxygen species (ROS) during their metabolism. Oxidative damage to cellular DNA can lead to mutations and may, therefore, play an important role in the initiation and progression of multistage carcinogenesis. The changes in DNA such as base modification, rearrangement of DNA sequence, miscoding of DNA lesion, gene duplication and the activation of oncogenes may be involved in the initiation of various cancers. Elevated levels of ROS and down regulation of ROS scavengers and antioxidant enzymes are associated with various human diseases including various cancers. ROS are also implicated in diabtes and neurodegenerative diseases. ROS influences central cellular processes such as proliferation a, apoptosis, senescence which are implicated in the development of cancer. Understanding the role of ROS as key mediators in signaling cascades may provide various opportunities for pharmacological intervention.