Heme Iron Intake Research Articles

Diet and genetic factors associated with iron status in middle-aged women

Gene mutations associated with iron overload have been identified. How food and nutrient intakes affect iron status in persons who may be at risk of iron overload because their genetic status is unknown. The objective was to determine the relation between food and nutrient intakes, HFE genotype, and iron status. Foods and nutrients associated with iron stores, with adjustment for gene mutations associated with hemochromatosis, were explored. A prospective cohort of women aged 35-69 y (the UK Women's Cohort Study) provided information on diet through a questionnaire and food diary; 6779 women in the cohort provided cheek cell samples, blood samples, or both, which were genotyped for C282Y and H63D mutations, and 2489 women also had their iron status assessed. Relations between serum ferritin and iron intake were investigated by using multiple linear regression, with adjustment for potential confounders. The strongest dietary association with serum ferritin concentration was a positive association with heme iron and not with nonheme or total iron. Weaker positive associations were seen with red and white meat, and negative associations were seen with total energy and white and brown whole-meal bread, independent of genotype and other potential confounders. The effect of genotype on ferritin concentrations primarily occurred after menopause, at which time a strong interaction between genotype and heme iron intake was observed. Other factors associated with serum ferritin concentrations were age, body mass index, blood donation, menopausal status, and HFE genotype. Postmenopausal women eating a diet rich in heme iron and who were C282Y homozygotes had the highest serum ferritin concentrations.

Food Frequency Questionnairefor Assessing Infant Iron Nutrition

A food frequency questionnaire (FFQ) was developed and tested for assessing iron nutrition in infants through comparison with a three-day food record (3d-FR) and measures of iron status. Parents of 148 infants aged eight to 26 months completed a 3d-FR and an FFQ. Blood was collected for measures of hemoglobin (Hgb), ferritin, and transferrin receptor (sTfR). Iron deficiency anemia and iron depletion (ferritin < or =12 microg/L) were found in 9% and 26% of infants, respectively. The intakes of energy, total iron, heme and non-heme iron, vitamin C, and dietary fibre determined by the FFQ were associated with the intakes of the same nutrient determined by the 3d-FR (p<0.05). The intakes of energy, total iron, non-heme and heme iron, vitamin C, and fibre were significantly higher when estimated by the FFQ than by the 3d-FR. Total and heme iron intakes determined by the FFQ were significantly associated with serum ferritin, sTfR, and the sTfR:ferritin ratio (p<0.05). However, iron intakes explained <10% of the variability in iron status. Despite relative validity of the FFQ for evaluating differences in energy, iron, vitamin C, and fibre intake compared with a 3d-FR, FFQs need further development before they can be used to advance assessment of iron intake and status in infants.

Interaction Among Heme Iron, Zinc, and Supplemental Vitamin C Intake on the Risk of Lung Cancer: Iowa Women's Health Study

: Redox-active iron present at physiological levels in the pulmonary epithelial lining fluid may lead to damage of lung tissue under some circumstances. For example, factors that increase potential for oxidative stress, such as higher intake of heme iron or higher intake of vitamin C in the presence of high intake of iron, might increase the risk of lung cancer, whereas higher intake of the antioxidant zinc might decrease that risk. During 16 yr of follow-up, 34,708 postmenopausal women, aged 55-69 yr at baseline who completed a food-frequency questionnaire for the Iowa Women's Health Study, were followed for 700 incident lung cancers. When subjects were stratified by intake of vitamin C supplements, among women who took vitamin C supplements of >500 mg/day, after adjusting for age, total energy intake, cigarette smoking, alcohol consumption, and dietary zinc or dietary heme iron intake, relative risks across categories of dietary heme iron intake were 1.0, 0.85, 0.93, 1.32, 1.70, and 3.77 (P for trend = 0.05; P for interaction = 0.08), whereas corresponding figures for dietary zinc intake were 1.0, 1.15, 0.71, 0.84, 0.61, and 0.11 (P for trend = 0.12; P for interaction = 0.04). The strength of the associations of heme iron and zinc intake with lung cancer appeared to be stronger with increasing levels of vitamin C supplement intake. Our results suggest that high dietary heme iron intake may increase the risk of lung cancer, whereas high dietary zinc may decrease the risk of lung cancer among postmenopausal women who consume high-dose vitamin C supplements. This finding may be of particular importance to smokers, for whom vitamin C supplementation is a common recommendation.

Iron, zinc, and alcohol consumption and mortality from cardiovascular diseases: the Iowa Women’s Health Study

The relation between iron status and atherosclerosis has long been a topic of debate. We examined associations of cardiovascular disease (CVD) mortality with dietary intakes of iron (a possible prooxidant), zinc (a possible antioxidant), and alcohol (a disruptor of iron homeostasis). Postmenopausal women (n = 34 492) aged 55-69 y at baseline, who completed a food-frequency questionnaire, were followed for CVD mortality over 15 y. Among women who consumed >/=10 g alcohol/d, after adjustment for CVD risk factors in a model that contained dietary heme iron, nonheme iron, and zinc intakes, dietary heme iron showed a positive association, dietary nonheme iron showed a U-shaped association, and dietary zinc showed an inverse association with CVD mortality. For example, the relative risks (RRs) for categories of dietary heme iron were 1.0, 1.46, 1.52, 1.73, and 2.47 (P for trend = 0.04); corresponding RRs for dietary nonheme iron were 1.0, 0.93, 0.63, 0.83, and 1.20 (P for quadratic term = 0.02). The corresponding RRs for dietary zinc were 1.0, 0.61, 0.59, 0.57, and 0.37 (P for trend = 0.07). In an analysis restricted to those who consumed >/=30 g alcohol/d, the risk gradients strengthened. Our results suggest that a higher intake of heme iron might be harmful, whereas a higher intake of zinc might be beneficial in relation to CVD mortality in the presence of a trigger that can disturb iron homeostasis, such as alcohol consumption.

Heme iron, zinc and upper digestive tract cancer: The Iowa Women's Health Study

We examined associations among dietary heme iron as a possible pro-oxidant, dietary zinc as a possible antioxidant, and the incidence of upper digestive tract cancer; 34,708 postmenopausal women, aged 55-69 years at baseline who completed a food frequency questionnaire, were followed 16 years. There were 75 upper digestive tract cancer cases (52 gastric cancer and 23 esophageal cancer). When heme iron and zinc were mutually adjusted, in dose-response manners, heme iron intake was positively associated with the risk of upper digestive tract cancer, while zinc intake was inversely associated with risk. After adjusting for age, total energy intake, cigarette smoking and alcohol consumption, relative risks for quintiles of heme iron intake were 1.0, 1.53, 2.15, 3.05 and 2.83 (p for trend = 0.06) and corresponding relative risks for zinc intake were 1.0, 0.86, 0.42, 0.37 and 0.13 (p for trend < 0.01). Additional adjustment for body mass index, physical activity, hormone replacement therapy, multivitamin intake and intake of saturated fat, vitamin C, vitamin E and folate did not change the results. Higher intake of heme iron is associated with higher risk, while higher intake of zinc is associated with lower, risk of upper digestive tract cancer.

Effect of Dietary Factors on Incidence of Type 2 Diabetes: A Systematic Review of Cohort Studies

We systematically reviewed cohort studies on the effect of nutrient and food intake (except for alcohol) on the incidence of type 2 diabetes, which had been published in English as of May 2004. Using the MEDLINE (PubMed) database as well as reference lists of searched papers, 15 individual cohort studies (a total of 31 papers) were identified. The number of subjects (n= 895-85,060), follow-up length (5.9-23 y), the number of diabetes cases (n= 74-4,085), dietary assessment method used (simple food questionnaire, food frequency questionnaire, food frequency interview, diet history interview, and 24-h recall), and method of case ascertainment (questionnaire, oral glucose tolerance test, fasting glucose level, death certificate, and nationwide registry) varied among studies. For nutrients, intakes of vegetable fat, polyunsaturated fatty acid, dietary fiber (particularly cereal fiber), magnesium, and caffeine were significantly inversely correlated and intakes of trans fatty acid and heme-iron, glycemic index, and glycemic load were significantly positively correlated with the incidence of type 2 diabetes in several papers. For foods and food groups, several papers showed significantly decreased risk for type 2 diabetes with the higher consumption of grain (particularly whole grain) and coffee, and significantly increased risk with processed meat consumption. Because all the studies were carried out in Western countries, however, research in non-Western countries including Japan is needed.

Dietary haem iron and coronary heart disease in women

A role for iron in the risk of ischaemic heart disease has been supported by in vitro and in vivo studies. We investigated whether dietary haem iron intake is associated with coronary heart disease (CHD) risk in a large population-based cohort of middle-aged women. We used data of 16 136 women aged 49-70 years at recruitment between 1993 and 1997. Follow-up was complete until 1 January 2000 and 252 newly diagnosed CHD cases were documented. Cox proportional hazards analysis was used to estimate hazard ratios of CHD for quartiles of haem iron intake, adjusted for cardiovascular and nutritional risk factors. We stratified by the presence of additional cardiovascular risk factors, menstrual periods, and antioxidant intake to investigate the possibility of effect modification. High dietary haem iron intake was associated with a 65% increase in CHD risk [hazard ratio (HR)=1.65; 95% confidence interval (CI): 1.07-2.53], after adjustment for cardiovascular and nutritional risk factors. This risk was not modified by additional risk factors, menstruation, or antioxidant intake. The results indicate that middle-aged women with a relatively high haem iron intake have an increased risk of CHD.

The Effect of Dietary Factors on Hemochromatosis Disease Expression in C282Y Homozygotes.

Background. Hereditary hemochromatosis (HHC) is a common inherited disorder and the vast majority of cases are associated with HFE gene mutations; about 80% are homozygous for the C282Y HFE mutation. Although homozygosity for C282Y is relatively common among individuals of northern European descent, the penetrance, as measured by clinically relevant iron overload, is low. Both environmental and genetic factors have been implicated in modulating disease expression. Most clinicians and patients attribute at least some of the observed variation to differences in dietary patterns.Methods: 28 C282Y homozygous subjects who had completed de-ironing therapy at our center, and were on stable maintenance phlebotomy treatments, participated in a previously validated dietary survey. We examined the influence of dietary iron, heme iron, fiber, ascorbic acid and alcohol intake on disease expression as measured by liver iron, phlebotomy-mobilized iron and maintenance phlebotomy requirement.Results. We developed a maintenance iron score (Maint Fe) which was the iron in milligrams removed per month by phlebotomy treatments in order to maintain serum ferritin in the 25–75 μG/L range. Maint Fe ranged from 36.8–203 mg/month in our patients (87.8 ± 37.7). Liver iron ranged from 30.5 to 505.4 micromoles per gram dry weight (192.7 ± 123). Phlebotomy-mobilized iron ranged from 2.35–18.03 G (6.43 ± 4.08). The Spearman's Rank Correlation was used to compare dietary parameters with each of the above measures of disease expression. No significant correlation was found.Conclusions. Disease expression varied considerably in our C282Y homozygous subjects as measured by liver iron, phlebotomy-mobilized iron and Maint Fe. The observed variation is not explained by variations in dietary iron, fiber, ascorbic acid or ethanol intake. Our data suggests that other unknown environmental variables or alternatively, modifier genes, may play a role in modulating disease expression in these patients. Contrary to popular belief, dietary variation does not appear to play a major role.

A prospective study of red meat consumption and type 2 diabetes in middle-aged and elderly women: the women's health study.

The aim of this study was to prospectively assess the relation between red meat intake and incidence of type 2 diabetes. Over an average of 8.8 years, we evaluated 37,309 participants in the Women's Health Study aged >/=45 years who were free of cardiovascular disease, cancer, and type 2 diabetes and completed validated semiquantitative food frequency questionnaires in 1993. During 326,876 person-years of follow-up, we documented 1,558 incident cases of type 2 diabetes. After adjusting for age, BMI, total energy intake, exercise, alcohol intake, cigarette smoking, and family history of diabetes, we found positive associations between intakes of red meat and processed meat and risk of type 2 diabetes. Comparing women in the highest quintile with those in the lowest quintile, the multivariate-adjusted relative risks (RRs) of type 2 diabetes were 1.28 for red meat (95% CI 1.07-1.53, P < 0.001 for trend) and 1.23 for processed meat intake (1.05-1.45, P = 0.001 for trend). Furthermore, the significantly increased diabetes risk appeared to be most pronounced for frequent consumption of total processed meat (RR 1.43, 95% CI 1.17-1.75 for >/=5/week vs. <1/month, P < 0.001 for trend) and two major subtypes, which were bacon (1.21, 1.06-1.39 for >/=2/week vs. <1/week, P = 0.004 for trend) and hot dogs (1.28, 1.09-1.50 for >/=2/week vs. <1/week, P = 0.003 for trend). These results remained significant after further adjustment for intakes of dietary fiber, magnesium, glycemic load, and total fat. Intakes of total cholesterol, animal protein, and heme iron were also significantly associated with a higher risk of type 2 diabetes. Our data indicate that higher consumption of total red meat, especially various processed meats, may increase risk of developing type 2 diabetes in women.

Meat and Meat Products Consumption in Italy: Contribution to Trace Elements, Heme Iron and selected B Vitamins supply

This study was undertaken to estimate the contribution of meat and meat products consumption to the daily intakes of trace elements (Fe, Zn, Cu, Se), heme iron, and selected B vitamins (thiamine, riboflavin, niacin) in Italy. Meat and meat products were selected on the basis of their consumption frequency reported by the most recent nationwide dietary individual survey carried out in Italy (INN-CA study). The daily intakes of total iron and heme iron were 1.65 and 1.13 mg/person/day. Zinc intake was 3.65 mg/person/day. Beef made the main contribution to iron, heme iron, and zinc daily intakes. Copper daily intake was 107.3 microg/person/day, with meat products provided the highest contribution (40 microg/person/day). Daily intake of selenium (7.14 microg/person/day) was provided mainly by poultry consumption. Thiamine intake was 228 microg/person/day, and meat products were the main source (110 microg/person/day). Riboflavin intake was 136 microg/person/day, with both beef and meat products as the main contributors (40 microg/person/day). Niacin intake was 7.53 mg/person/day, and poultry was the main source (2.28 mg/person/day). Meat and meat products were a valuable source of micronutrients, supplying 47, 48, and 24% of zinc, niacin, and thiamin daily requirements, respectively, and over 10% of iron, copper, selenium, and riboflavin daily average requirement values of the italian RDAs calculated for the population involved in the survey (INN-CA study).

Heme iron, zinc, alcohol consumption, and colon cancer: Iowa Women's Health Study.

We examined associations among colon cancer incidence and dietary intake of heme iron, a possible prooxidant, zinc, a possible antioxidant, and alcohol, a disruptor of iron homeostasis. During 15 years of follow-up, 34 708 postmenopausal women, aged 55-69 years at baseline who completed a food-frequency questionnaire for the Iowa Women's Health Study, were followed for incident colon cancer. After adjusting for each micronutrient, the relative risks for proximal colon cancer increased more than twofold across categories of heme iron intake (P(trend) =.01) and the corresponding relative risks decreased more than 50% across categories for zinc intake (P(trend) =.01). The positive association with heme iron and the inverse association with zinc intake were stronger among women who consumed alcohol than among those who did not. Zinc intake was also associated with a decreased risk of distal colon cancer (P(trend) =.03), regardless of alcohol or heme iron consumption. Our results suggest that intake of dietary heme iron is associated with an increased risk of proximal colon cancer, especially among women who drink, but that intake of dietary zinc is associated with a decreased risk of both proximal and distal colon cancer.

Cardiovascular News

Cardiovascular News

Iron Status of Young Males and Females Performing Weight-Training Exercise

To determine the effect of weight training on measures of iron status in young males and females. Forty (27 female, 13 male) non-weight-trained college age subjects participated in a 12-wk weight-training program conducted 3 d.wk-1. Blood samples and food diaries were obtained pretraining and at 4-wk intervals. Blood was analyzed for hemoglobin, hematocrit, serum iron (SI), total iron binding capacity (TIBC), transferrin saturation (TS), serum ferritin (SF), soluble transferrin receptor (sTfR), and creatine kinase (CK). Subjects were grouped by SF level (FL, females < or = 20 microg.L-1; FN, females > 20 microg.L-1; ML, males < or = 45 microg.L-1; MN, males > or = 50 microg.L-1) to determine the impact of initial iron status on measured responses. Weight training increased strength and fat-free mass and decreased levels of percent body fat. Hemoglobin concentration declined after 12 wk of training (13.7 +/- 1.6 vs 13.2 +/- 1.7 g.dL-1), independent of gender or initial iron status. Only the MN group experienced a decline in SF level after 8 wk of training (129.7 +/- 77.9 vs 102.0 +/- 57.8 microg.L-1). No significant changes were observed for hematocrit, SI, TIBC, TS, sTfR, or CK measures. Total iron intake, but not heme or bioavailable iron intakes, declined at the 12th week of training compared with baseline (13.4 +/- 6.5 vs 10.7 +/- 4.8 mg.d-1) and was not significantly correlated with hematological or iron status measures. Hemoglobin concentration declines without alterations in SI, TIBC, TS, or sTfR after 12 wk of weight training. The SF level of males with adequate iron status is lowered with weight training but not among females or males with low iron status.

Dietary iron intake and Type 2 diabetes incidence in postmenopausal women: the Iowa Women's Health Study.

Recently, a clear biological link between iron metabolism and diabetes has emerged from epidemiological and experimental studies. We carried out a prospective study of dietary iron intake and incidence of Type 2 diabetes. 35,698 postmenopausal women initially aged 55 to 69 years were followed for 11 years. Diet was assessed with a food frequency questionnaire at baseline. Intake of heme iron showed a positive association with incident Type 2 diabetes; the relative risks were 1.0, 1.07, 1.12, 1.14, and 1.28 across quintiles of heme iron (p trend =0.02) after adjustment for non-dietary and dietary risk factors. Heme iron showed a weak positive association among non-drinkers, but the association appeared to be stronger among subjects who consumed more alcohol. For example, in a model restricted to those who drank alcohol at least 15 g/day, adjusted relative risks across quintiles of heme iron were 1.0, 2.26, 3.22, 1.92, and 4.42 (p trend =0.05); and consumers of 30 g/day of more of supplemental iron had an adjusted relative risk equal to 3.03 (95% CI, 1.29-7.12)], compared to those who took no iron supplement. Non-heme iron was inversely associated with incidence of Type 2 diabetes. Amongst non-drinkers adjusted relative risks were 1.0, 0.83, 0.87, 0.72, and 0.67 across quintiles (p trend <0.01). This inverse association was lost among drinkers, in whom there was no association of diabetes incidence with non-heme iron. Greater dietary heme-iron intake and/or supplemental iron were associated with an increased risk of Type 2 diabetes, especially amongst those who drink alcohol.

Dietary iron intake and blood donations in relation to risk of type 2 diabetes in men: a prospective cohort study

Excessive iron stores may promote insulin resistance and lead to the development of type 2 diabetes. However, prospective data relating iron intake and blood donations (determinants of body iron stores) to diabetes incidence are limited. We examined iron intake and blood donations in relation to the incidence of type 2 diabetes. We followed men aged 40-75 y who participated in the Health Professionals' Follow-up Study; were free of diabetes, cardiovascular disease, and cancer in 1986; and provided dietary data (n = 38 394). Of those participants, 33 541 also provided a history of blood donation during the past 30 y in 1992. During 12 y of follow-up, we ascertained 1168 new cases of type 2 diabetes. After adjustment for age, body mass index, and other diabetes risk factors, total iron intake was not associated with the risk of type 2 diabetes. Intakes of total heme iron [multivariate relative risk (RR) for extreme quintiles: 1.28; 95% CI: 1.02, 1.61; P for trend = 0.045] and of heme iron from red meat (RR: 1.63; 1.26, 2.10; P for trend < 0.001) were associated with an increased risk. However, heme-iron intake from sources other than red meat was not associated with diabetes risk (RR: 0.99; 0.81, 1.22). No significant associations were found between blood donation and the risk of type 2 diabetes. Heme-iron intake from red meat sources is positively associated with the risk of type 2 diabetes. Total iron intake, heme-iron intake from non-red meat sources, and blood donations are not related to the risk of type 2 diabetes.

Body iron stores and their determinants in healthy postmenopausal US women

Data on the determinants of body iron stores in middle-aged women are sparse. We prospectively evaluated nondietary and dietary determinants of iron stores. Using blood samples collected in 1989-1990, we measured plasma ferritin concentrations in 620 healthy postmenopausal women aged 44-69 y who participated in the Nurses' Health Study. Food-frequency questionnaires completed in 1980, 1984, and 1986 were used to calculate average dietary intakes. Generalized linear regression and multiple logistic regression models were used to assess the association between plasma ferritin and its determinants. Among these postmenopausal women, the median plasma ferritin concentration was 73.8 ng/mL (interquartile range: 41.6-125.8 ng/mL), 2.7% were iron depleted (ferritin concentration < 12 ng/mL), and 9.8% had an elevated ferritin concentration (> 200 ng/mL). Age, time since menopause, time since the last postmenopausal hormone (PMH) use, body mass index, iron supplement use, and alcohol and heme-iron intakes were positively associated with ferritin concentrations, whereas PMH use, physical activity, aspirin use, and gastrointestinal ulcer were inversely related. The association between heme-iron intake and ferritin was most apparent among the women who consumed > 30 g alcohol/d. Our prospective data confirm that in postmenopausal women, intakes of heme iron, supplemental iron, and alcohol are dietary determinants of plasma ferritin, and age, PMH use, body mass index, physical activity, aspirin use, and gastrointestinal ulcer are nondietary determinants.

Experiences of a Community-Based Dietary Intervention to Enhance Micronutrient Adequacy of Diets Low in Animal Source Foods and High in Phytate: A Case Study in Rural Malawian Children

A community-based dietary diversification/modification intervention, employing a quasiexperimental design with a nonequivalent control group, was conducted in two intervention and two control villages in rural Southern Malawi. The aim was to enhance the content and bioavailability of micronutrients in maize-based diets of stunted children ages 30-90 mo. Efficacy was evaluated through a comparison of the changes in knowledge and practices, anthropometry, malaria screening, hemoglobin and hair zinc after 12 mo, common infections monthly postintervention and nutrient adequacy postintervention via 24-h recalls. Intervention diets were more diverse and of higher quality than the control diets, supplying significantly more animal source foods, especially soft-boned fish, but less phytic acid (p < 0.01). Median intakes of energy, protein, calcium, available zinc, heme iron and vitamin B-12 were greater (p < 0.05) in intervention compared to the control groups; some spread of knowledge and practices to the control groups occurred. Intervention enhanced Z-scores for mid-upper-arm circumference and arm muscle area (p < 0.001), but had no impact on weight or height gain. After controlling for baseline variables, mean hemoglobin was higher (107 vs. 102 g/L; p < 0.01) postintervention, whereas incidence of anemia and common infections were lower in the intervention groups compared to the control groups, with no change in malaria or hair zinc status. Dietary strategies reduced the prevalence of inadequate intakes of protein, calcium, zinc and vitamin B-12, but not iron, because fish was the major source of animal food consumed. More efforts to raise small animals and promote their consumption are needed to enhance dietary quality and ensure optimal growth, health and cognitive development in young Malawian children.

Ascorbic acid from lime juice does not improve the iron status of iron-deficient women in rural Mexico

Although ascorbic acid (AA) increases dietary iron bioavailability, there has been no food-based community trial of its efficacy in improving iron status. The objective was to assess the efficacy of 25 mg AA as agua de limón (limeade), consumed with each of 2 daily meals, in improving the iron status of iron-deficient women. Two rural Mexican populations were randomly assigned to an AA or a placebo group, each with 18 iron-deficient women. The AA group was given 500 mL limeade containing 25 mg AA twice a day, 6 d/wk, for 8 mo. The placebo group was given a lime-flavored beverage free of AA or citric acid. Beverages were consumed within 30 min of 2 main daily meals. Data were collected on morbidity (3 times/wk), dietary intake (on 6 d), socioeconomic status, parasites (twice), medical history, and response to treatment. Blood samples at 0, 2, 4, 6, and 8 mo were analyzed for hemoglobin, plasma AA, plasma ferritin, transferrin receptors, and C-reactive protein. AA intake was significantly (P < 0.0001) higher in the AA group, but nonheme iron, heme iron, and phytic acid intakes did not differ significantly. Plasma AA was significantly (P < 0.01) higher in the AA group at 2, 4, 6, and 8 mo. There were no final differences between groups in hemoglobin, plasma ferritin, or transferrin receptor concentrations or in the ratio of transferrin receptors to plasma ferritin after control for initial concentrations. Increasing dietary AA by 25 mg at each of 2 meals/d did not improve iron status in iron-deficient women consuming diets high in phytate and nonheme iron.

#80 Dietary iron and hemeiron as risk factors for myocardial infarction

Abstract PURPOSE: Several epidemiological and experimental studies have suggested a potential association between high levels of dietary iron/hemeiron and risk of acute myocardial infarction (AMI). Lean meat, a rich source of iron and hemeiron, is promoted because it is relatively low in fat and cholesterol. This leads to the concern that lean meat may increase risk for AMI and that we should reconsider its promotion. We investigated whether individuals who consume more iron and hemeiron were at increased risk for AMI. METHODS: We analyzed dietary intake of iron and hemeiron among 2198 participants in a nutrition survey in the province of Nova Scotia, Canada. Linkage with hospital discharge records, physicians' administrative records and vital statistics enabled us to analyze AMI during an eight-year follow up period. Using logistic regression, AMI cases were compared to those without AMI, while adjusting for differences in age, gender, smoking, body mass index, diabetes, socioeconomic background, dietary lipids, saturated fat, cholesterol and total energy intake. RESULTS: During the eight years following the survey, 94 (4.3%) participants had an AMI, of which 17 were fatal. Participants in the highest iron intake tertile had reduced risk of AMI, compared to those in the lowest tertile (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.34–1.05). Similarly, participants in the highest hemeiron intake tertile had reduced risk of AMI (OR, 0.65; 95% CI, 0.37–1.14). CONCLUSION: Based on the present results, showing no increased risk for AMI with high intake of iron and hemeiron, and results from the literature showing that Nova Scotians have a poorer diet, high obesity prevalence and among the highest cardiovascular disease and cancer rates in Canada, we conclude that there is no need for immediate reconsideration of promotion of lean meat in this province.

Diet and iron status of nonpregnant women in rural Central Mexico , ,

Few studies have examined the relation of iron status to diet in populations from developing countries with high levels of iron deficiency and diets of poor quality. The objective was to identify nutrients, dietary constituents, and foods that are associated with better iron status in a rural Mexican population. A prospective cohort study was conducted in rural central Mexico. The subjects were 125 nonpregnant women aged 16-44 y. During the 12 mo before blood collection, food intakes were assessed repeatedly by a combination of dietary recalls, food weighing, and food diaries [mean (+/-SD) days of food intake data: 18.8 +/- 5.9 d]. Hemoglobin, hematocrit, and plasma ferritin were measured at the end of the study. Higher plasma ferritin concentrations were associated with greater intakes of nonheme iron and ascorbic acid after control for age, BMI, breast-feeding, season, and the time since the birth of the last child. Higher ascorbic acid intakes, but not higher intakes of heme and nonheme iron, predicted a lower risk of low hemoglobin and hematocrit values after control for the background variables. Consumption of the alcoholic beverage pulque predicted a lower risk of low ferritin and low hemoglobin values. Seasonal variation in ferritin, hemoglobin, and hematocrit values was observed. Better iron status was associated with greater intakes of foods containing nonheme iron and ascorbic acid. PULQUE:a beverage containing iron, ascorbic acid, and alcohol-may influence the iron status of women in rural central Mexico.