Maize Intake Research Articles

Stable isotope evidence for pre-colonial maize agriculture and animal management in the Bolivian Amazon.

Over the past decade, multidisciplinary research has seen the Amazon Basin go from a context perceived as unfavourable for food production and large-scale human societies to one of 'garden cities', domestication, and anthropogenically influenced forests and soils. Nevertheless, direct insights into human interactions with particular crops and especially animals remain scarce across this vast area. Here we present new stable carbon and nitrogen isotope data from 86 human and 68 animal remains dating between CE ~700 and 1400 from the Llanos de Mojos, Bolivia. We show evidence of human reliance on maize agriculture in the earliest phases before a reduction in the dietary importance of this crop between CE 1100 and 1400. We also provide evidence that muscovy ducks (Cairina moschata), the only known domesticated vertebrate in the South American lowlands, had substantial maize intake suggesting intentional feeding, or even their domestication, from as early as CE 800. Our data provide insights into human interactions with Amazonian ecosystems, including direct evidence for human management of animals in pre-colonial contexts, further enriching our understanding of human history in what was once considered a 'counterfeit paradise'.

Maize consumption and circulating aflatoxin levels in Mexican middle- and older-aged adults: a cross-sectional analysis.

Maize is frequently contaminated by aflatoxin B1 (AFB1), an established liver carcinogen. The objective of this study is to estimate the effect of maize and maize tortilla consumption on AFB1-lysine adduct (AFB1-lys) concentrations in middle- and older-aged adults living in south and eastern Mexico. We conducted a cross-sectional analysis in a representative sample of 915 adults aged ≥40 y living in south and eastern Mexico in 2018-2019. Maize and maize tortilla intake were estimated using a food frequency questionnaire. Intake of maize tortillas made from store-purchased masa or bought in a tortilleria, from homemade masa, and from store-bought maize flour was assessed. AFB1-lys in serum was quantified using state-of-the-art isotope-dilution liquid chromatography-mass spectrometry. We assessed the relationship between maize and maize tortilla consumption and AFB1-lys by fitting linear regression models that accounted for the complex survey design. Median maize intake was 307 g/d [quartile 1 (Q1)-quartile 3 (Q3) = 165, 554]. Maize tortillas represented 77% of total maize consumption, with a median consumption of 252 g/d (Q1-Q2 = 120, 462). After multivariable adjustment, for every 30 g of maize consumed (1 tortilla equivalent), circulating AFB1-lys incremented by 2.1% [95% confidence interval (CI): 0.9%, 3.4%]. For every maize tortilla consumed, the concentration of circulating AFB1-lys was 2.0% (95% CI: 0.6%, 3.4%) higher. The corresponding estimate for homemade masa tortilla was 2.8% (95% CI: 1.1%, 4.6%). The magnitude of the estimates for tortillas made from store-purchased masa or bought in a tortilleria and those made from store-bought maize flour was minimal. Maize and maize tortilla intake was associated with AFB1-lys concentrations. This association appears to be driven by the consumption of tortillas made from homemade masa.

Investigation of the Transfer Influence and Health Threat from the Intake of Maize and Exposure to Soil in Different Geological Formations in Akwa Ibom State, Nigeria

The consumption of maize contaminated by radionuclides may pose certain health challenges to the body. This research was conducted to investigate the possible danger radionuclides could cause. Soil and maize samples were obtained from different geological formations. They were analyzed using a Sodium Iodide-Thalium (NaI(TI)) detector. The activity concentration results from the soil samples show the highest values of 238U, 232Th and 40K as 14.74±0.26 Bqkg-1, 40.34±0.73 Bqkg-1 and 444.89±8.12 Bqkg-1 respectively which correspond to Ogwashi-Asaba, Ogwashi-Asaba and Imo shale geological formations. The findings from maize samples indicate the maximum values of 238U, 232Th and 40K as 16.46±0.25 Bqkg-1, 18.12±0.46 Bqkg-1 and 435.17±7.89 Bqkg-1 respectively which correspond to Benin, Ogwashi-Asaba and Ogwashi-Asaba geological formations. The outcome of mean transfer factor of 238U, 232Th and 40K corresponds to 0.942, 0.460 and 1.002. The absorbed dose rate ranges from 28.91 nGyh-1 to 36.08 nGyh-1. Radium equivalent varies from 49.40 Bqkg-1 to 98.75 Bqkg-1. Almost equal value (0.15×10-3) was assessed for the mean excess lifetime cancer risk. Although the activity concentration noted from maize is high, the evidence obtained shows that there is no geological formation with health risk problem as the external, internal and radioactivity hazard indices are less than unity.

Investigation of the Transfer Influence and Health Threat from the Intake of Maize and Exposure to Soil in Different Geological Formations in Akwa Ibom State, Nigeria

The consumption of maize contaminated by radionuclides may pose certain health challenges to the body. This research was conducted to investigate the possible danger radionuclides could cause. Soil and maize samples were obtained from different geological formations. They were analyzed using a Sodium Iodide-Thalium (NaI(TI)) detector. The activity concentration results from the soil samples show the highest values of 238U, 232Th and 40K as 14.74±0.26 Bqkg-1, 40.34±0.73 Bqkg-1 and 444.89±8.12 Bqkg-1 respectively which correspond to Ogwashi-Asaba, Ogwashi-Asaba and Imo shale geological formations. The findings from maize samples indicate the maximum values of 238U, 232Th and 40K as 16.46±0.25 Bqkg-1, 18.12±0.46 Bqkg-1 and 435.17±7.89 Bqkg-1 respectively which correspond to Benin, Ogwashi-Asaba and Ogwashi-Asaba geological formations. The outcome of mean transfer factor of 238U, 232Th and 40K corresponds to 0.942, 0.460 and 1.002. The absorbed dose rate ranges from 28.91 nGyh-1 to 36.08 nGyh-1. Radium equivalent varies from 49.40 Bqkg-1 to 98.75 Bqkg-1. Almost equal value (0.15×10-3) was assessed for the mean excess lifetime cancer risk. Although the activity concentration noted from maize is high, the evidence obtained shows that there is no geological formation with health risk problem as the external, internal and radioactivity hazard indices are less than unity.

Abstract 842: Maize consumption and circulating aflatoxin B1 levels in Mexican adults

Abstract Objective: To estimate the impact of maize consumption on aflatoxin B1 [AFB1] levels, a potent carcinogen, in Mexican adults living in south and eastern Mexico. Methods: Study participants were women and men ≥40 years of age living in five high hepatocellular carcinoma burden states who participated in Mexico’s 2018 National Health and Nutrition Survey, a stratified, multi-stage, and cluster survey probability sampling household survey that is representative of the Mexican population. We estimated the consumption of maize intake in grams per day using a previously validated semi-quantitative food frequency questionnaire with a time reference of the previous seven days. We determined circulating AFB1-albumin lysine adduct [AFB1-lys] levels in serum using liquid chromatography. Guided by subject-matter knowledge we fit multivariable linear regression models that considered the survey design and included age, sex, residence, ethnicity, education, socioeconomic status, and foods known to be contaminated with aflatoxins including peanuts, rice, dried chili, milk, and cheese. Results: Among the 915 participants, median maize consumption was 307 grams per day [Q1-Q3: 165 - 554]. Maize tortillas contributed 80% of the total maize consumption. The median maize tortillas consumption was 252 grams per day [Q1-Q3: 120 - 462], approximately 8 tortillas per day. Prevalence of AFB1-lys detection was 92% and median levels were 0.127 pg/µL [Q1-Q3: 0.052 - 0.449]. After adjusting for factors that may affect aflatoxin levels, for every 100 grams of maize consumption AFB1-lys levels were 7.4% [β: 0.071, 95% CI: 0.030 - 0.112] higher. And for every tortilla consumed [30 g of maize], we observed a 2.0% [β: 0.020, 95% CI: 0.006 - 0.034] higher level of circulating AFB1-lys. Conclusion: These findings indicate that maize and maize tortillas may be an important source of AFB1 exposure in the Mexican population. Mexico requires effective public health interventions to mitigate exposure to AFB1. Citation Format: Martin Lajous, Obed Solis-Martinez, Adriana Monge, John Groopman, Katherine A. McGlynn, Martin Romero, Carolina Batis, Hector Lamadrid-Figeuroa, Horacio Riojas-Rodriguez. Maize consumption and circulating aflatoxin B1 levels in Mexican adults [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 842.

Health risk assessment of heavy metals in soils and crops in a mining area (Au-Ag-Cu-trona-oil et al.) of the Nanyang Basin, Henan Province, China

Heavy metal distribution in mining areas has always been a hot research topic due to the special environment of these areas. This study aims to explore the impact of heavy metal pollution on soils and crops in the study area, ensure the safety of local crops and the health of local residents, and provide a basis for the subsequent environmental restoration and the prevention and control of environmental pollution. Based on the analysis of the heavy metal concentrations in local soils and crops, the study investigated the spatial distribution, pollution degrees, and potential ecological risks of heavy metals in the farmland of a mining area in the southeastern Nanyang Basin, Henan province, China explored the sources of heavy metals and assessed the health risks caused by crop intake. The results of this study are as follows. The root soils of crops in the study area suffered heavy metal pollution to varying degrees. The degree of heavy metal pollution in maize fields is higher than that in wheat fields, and both types of fields suffer the most severe Cd pollution. Moreover, the root soils of different crops suffer compound pollution. The root soils in the maize fields suffer severe compound pollution at some sampling positions, whose distribution is similar to that of the mining area. Cd poses the highest potential ecological risks among all heavy metals, and the study area mainly suffers low and moderate comprehensive potential ecological risks. The principal component analysis (PCA) shows that the distribution of Zn, Cd, Pb, and As in soils of the study area is mainly affected by anthropogenic factors such as local mining activities; the distribution of Cr and Ni is primarily controlled by the local geological background; the distribution of Hg is mainly affected by local vehicle exhaust emissions, and the distribution of Cu is influenced by both human activities and the geological background. Different cereal crops in the study area are polluted with heavy metals dominated by Cd and Ni to varying degrees, especially wheat. As indicated by the health risk assessment results, the intake of maize in the study area does not pose significant human health risks; however, Cu has high risks to human health, and the compound heavy metal pollution caused by the intake of wheat in the study area poses risks to the health of both adults and children. Overall, the soils and crops in the study area suffer a high degree of heavy metal pollution, for which mining activities may be the main reason.©2023 China Geology Editorial Office.

Multi-Target Element-Based Screening of Maize Varieties with Low Accumulation of Heavy Metals (HMs) and Metalloids: Uptake, Transport, and Health Risks

Mitigating heavy metals (HMs) contamination and ensuring the safe production of crops is of paramount importance for sustainable agriculture development. The purpose of the current field plot study was to select maize varieties with low HMs and metalloids in their edible parts but high accumulation in other parts. The cadmium (Cd), arsenic (As), lead (Pb), and chromium (Cr) contents of 11 maize varieties were measured by atomic absorption spectrometry, and the plant growth and bioconcentration factors (BFs) were examined. Furthermore, the average daily intake (ADDi) of HMs in maize grains was calculated to assess the associated health risks. The results revealed that the growth of variety TZ23 was minimally impacted HMs and metalloids. The grains of all of the tested maize varieties contained Cr, As, and Pb contents in accordance with National Food Safety Standards (NFSSs, GB2762-2017, ≤0.1 mg·kg−1), while the Cd concentration in grains of varieties QJN1, LSCR, and JN20 were 0.084 mg·kg−1, 0.094 mg·kg−1, and 0.077 mg·kg−1, respectively, in accordance with NFSSs. The translocation factor (TF) of As, Pb and Cr in the grains of 11 maize varieties were found to be less than 1. However, the TF of grain Cd in varieties LYN9, JYN9, and QJN3 exceeded 1. For varieties HNY21, TZ23, and LYN9, the TF of Cd, As, Pb, and Cr in the stems/leaves was less than 1. Cluster analysis revealed that the grains of variety HNY21 had the lowest accumulation capacity of all four HMs. Importantly, the variety JN20 exhibited a high accumulation capacity for Pb and a low capacity for As, while both varieties SKN11 and QJN3 had high accumulation capacities for Cd and low capacities for As. Health risk (HR) indices of the different age groups displayed an overall trend of children > elderly > young adult. Among the HMs and metalloids, Cd and Cr pose the greatest health risks of maize intake. Variety QJN3 posed a significant HR due to chronic toxicity. This study provides a scientific basis for multi-element pollution control and screening of maize varieties suitable for cultivation in mining areas and the remediation of HMs-contaminated soils.

Diazotrophic Bacteria Is an Alternative Strategy for Increasing Grain Biofortification, Yield and Zinc Use Efficiency of Maize.

Biofortification of cereal crops with zinc and diazotrophic bacteria is a sustainable solution to nutrient deficiency and hidden hunger. The inoculation of staple grain crops such as maize is increased with reducing productivity losses while improving nutrition and use efficiency under climatic extremes and weathered soils of tropical savannah. Therefore, objectives of our study were to evaluate the influence of seed inoculation with diazotrophic bacteria (No inoculation–Control, Azospirillum brasilense, Bacillus subtilis, and Pseudomonas fluorescens) together with residual effect of soil Zn (absence and presence) on growth, yield, Zn nutrition, Zn use efficiencies, and intake of maize in 2019 and 2020 cropping seasons. The inoculation of B. subtilis increased hundred grain mass and yield (14.5 and 17%), while P. fluorescens under residual Zn fertilization has improved shoot and grain Zn concentration in shoot (29.5 and 30.5%). and grain (25.5 and 26.2%), while improving Zn accumulation in shoot (33.8 and 35%) and grain (37.2 and 42%) of maize. The estimated Zn intake in maize was also increased with A. brasilense inoculation and residual Zn application. The Zn use efficiencies including Zn use efficiency, agro-physiological, and utilization efficiency was increased with B. subtilis, while applied Zn recovery was increased with A. brasilense inoculations under residual Zn fertilization. Zinc use efficiency was increased by 93.3 and 397% with inoculation of B. subtilis regardless of Zn application. Therefore, inoculation with B. subtilis and P. fluorescens along residual Zn fertilization is considered the most effective and sustainable strategy for agronomic biofortification of maize under harsh tropical conditions of Brazil.

Evaluation of the impact of transgenic maize BT799 on growth, development and reproductive function of Sprague-Dawley rats in three generations

BT799 was Bacillus thuringiensis-genetic modified (GM) maize, and Sprague-Dawley (SD) rats were treated with different diet formulations containing BT799 maize grain (33% and 66%) or its non-transgenic Zhengdan 958 (ZD958, 33% and 66%). The feeding lasted for 10 (P)/14 (F1 and F2) weeks. The reproductive capacity and pathological responses were detected in each generation of rats fed with BT799 and ZD958. During the growth and development of parental rats, each group showed the same trend in body weight gain and food intake, with a few fluctuations at individual time points. No statistically significant difference was observed in reproductive data (copulation index, fertility index, and live birth rate) of rats fed with transgenic maize compared with non-transgenic maize. We observed some apparent changes in reproductive data (sperm numbers and motility) and pathological responses (organ relative weights, hematological parameters, serum chemistry parameters, and sex hormone levels) among rats fed with BT799 maize grain. However, these differences were within the laboratory's historical normal range of control SD rats and not maize grain dose-dependent. These changes were not considered to be adverse or toxic. No significant difference in macroscopic or histological adverse effects was observed between rats consuming transgenic BT799 diet and non-transgenic diet. In conclusion, the long-term intake of BT799 maize was as safe as the corresponding non-transgenic maize for three-generation SD rats.

From the Atlantic coast to the lowland forests: Stable isotope analysis of the diet of forager–horticulturists in southern Brazil

AbstractIn this study, we analyze the diet of forager–horticulturalist societies of southeast South America through different isotopic markers (δ13Ccollagen, δ13Capatite, and δ15N). The economy of these populations was based on hunting, fishing, gathering, and, to a greater or lesser extent, horticulture, showing a different emphasis on each one of these options. The samples analyzed here were recovered from different environments, including the Atlantic coast, the highlands of the Brazilian plateau, and the lowland forests of the upper valleys of the Uruguay and Paraná rivers, within a general east–west sampling transect. Most of the samples correspond to individuals recovered from the Guarani and Itararé‐Taquara archeological units. We have also included a smaller sample of foragers clustered in the so‐called Vieira Tradition, perhaps with some food production, and two individuals buried in shell mounds (“sambaquis”) of the south Brazilian Atlantic coast (“Coastal Tradition”), whose economy was strongly based on marine resources and wild plants. The results indicate that, regardless of the archeological unit in question, the individuals recovered from the seashore settlements show a diet based mostly on marine protein, with a minor contribution of other resources, except in a Guarani sample, where a significant intake of maize is observed. The individuals recovered in the highlands of the Brazilian plateau (“Itararé‐Taquara”) present the highest incidence of plant consumption of the entire sample analyzed, within a C3 monoisotopic pattern, probably strongly influenced by the consumption of the araucaria pine nut, and no isotopic signals related to maize intake. Guarani samples recovered from sites located in tropical forests in the interior of the continent show an unquestionable and systematic impact of maize on the diet, in addition to an important consumption of C3 animal proteins. The individuals assigned to the so‐called Vieira Tradition show a diet based on C3 protein and both C3 and C4 lipids and carbohydrates. The latter could be related to a small consumption of maize. These results demonstrate the multidirectionality of subsistence strategies in southeastern South America during the late Holocene.

Potentially toxic element (PTE) levels in maize, soil, and irrigation water and health risks through maize consumption in northern Ningxia, China

BackgroundIndustrial and agricultural activities result in elevated levels of potentially toxic elements (PTEs) in the local environment. PTEs can enter the human body through the food chain and pose severe health risks to inhabitants. In this study, PTE levels in maize, soil, and irrigation water were detected, and health risks through maize consumption were evaluated.MethodsMaize, soil, and irrigation water samples were collected in northern Ningxia, China. Inductively coupled plasma-optical emission spectrometry was applied to determine the contents of six PTEs. Bioaccumulation factor was used to reflect the transfer potential of a metal from soil to maize. Health risks associated with maize consumption were assessed by deterministic and probabilistic estimation. Sensitivity analysis was performed to determine variables that pose the greatest effect on health risk results.ResultsThe levels of Pb and Cr in maize exceeded the standards, while the PTE levels in soil and irrigation water did not exceed the corresponding standards. The bioaccumulation factor values of the six PTEs in maize were all lower than 1 and followed the order of Cd > Zn = As > Cr > Cu > Pb. The hazard index (0.0986) was far less than 1 for all inhabitants implying no obvious non-carcinogenic risk. The carcinogenic risk value was 3.261 × 10− 5, which was lower than the maximum acceptable level of 1 × 10− 4 suggested by United States Environmental Protection Agency (USEPA). Females were at greater risk than males, and the age group of below 20 years had the greater risk among all the groups evaluated. Approximately 0.62% of inhabitants exceeded the level for non-carcinogenic risk, while 8.23% exceeded the level for carcinogenic risk. The As concentration and daily intake of maize contributed 35.8, and 29.4% for non-carcinogenic risk results as well as 61.0 and 18.5% for carcinogenic risk results.ConclusionsMaize was contaminated by Pb and Cr, whereas the associated soil and irrigation water were not contaminated by PTEs. Inhabitants would not suffer obvious harmful health risks through maize consumption. Arsenic level and daily intake of maize were the most sensitive factors that impact health risks.

Modeling the Potential of Household-Level Maize Processing to Reduce the Burden of Zinc Deficiency Among Women of Childbearing Age in Malawi

Abstract Objectives Dietary phytate is a potent inhibitor of zinc absorption. Phytate levels of cereals can be reduced by basic household processing techniques such as soaking, germinating, and fermenting. The objective of this study was to model the potential of such techniques to reduce the burden of zinc deficiency in Malawi, where high-phytate maize is a dietary staple. Methods Using nationally representative household consumption data and food composition tables, we estimated daily phytate and zinc intakes for individuals in Malawi. We then applied a mathematical model of zinc absorption based on total dietary zinc and phytate to calculate the apparent absorbed zinc for each individual. Using the Cut-Point method described by the Institute of Medicine, we determined the proportion of each physiological group with absorbed zinc below their mean requirements. We then simulated the reduction in dietary phytate resulting from maize processing and estimated the new burdens of zinc deficiency. We estimated the impact at various coverage levels and compared the results against an alternative model using zinc-biofortified maize. Results Nationally, 34% of females age 14–18 and 23% of females over age 18 were at risk of zinc deficiency. Only 13% of women of childbearing age met the zinc requirement for pregnancy, while less than 4% met the requirement for breastfeeding. The burden of zinc deficiency was highest in the South where maize intake was highest. The simulation of phytate reduction from household processing found that with 40% coverage, the proportion of at-risk females age 14–18 fell below 23%, while the proportion over age 18 fell to 14%. The potential benefits were greatest in the South, where the proportion of women at risk was reduced by over a third. Biofortification also reduced zinc deficiency, however the modeled impact of processing was greater than biofortification for all regions and subgroups. Conclusions Household food processing techniques may be an important strategy to reduce the burden of zinc deficiency among vulnerable women in Malawi. These techniques are low-cost and not widely practiced at present. Behavior change interventions to promote them must consider culture, gender norms, and drivers of food preference. Food-based approaches such as these should be given greater attention in nutrition and health policy and programming. Funding Sources None.

Influence of Customized Supplement on Voluntary Feed Intake and Nutrient Metabolism in Crossbred Calves

The present study was carried out to ascertain the effect of dietary inclusion of a customised supplement to farmers’ based diet on voluntary feed intake and nutrient metabolism in crossbred calves. In order to carry out the experiment, fifteen crossbred calves (18 months old; 166.53±4.93 kg mean BW) were randomly allocated to 3 groups (5 calves in each group) as CON, Treat and SBR, in a CRD for 30 days. The calves in CON (control) group were fed on cereal straw based diet with concentrate mixture as per the farmers’ practices, whereas, the calves in Treat were fed according to CON with additional customized supplement @ 0.25% of BW. The calves in SBR group were fed standard diet as per Kearl (1982). The intake (gd-1) of DM and OM was significantly Pandlt;0.01 higher in SBR than Treat and CON groups, while DM and OM intake as % of BW in Treat group has an intermediate position between SBR and CON groups. The concentrate intake (gd-1) was significantly Pandlt;0.001 higher in SBR followed by Treat and CON group, respectively. However, intake of wheat straw and green maize was found to be identical Pandlt;0.05 among all the groups. The digestibility coefficient of DM, OM, CP, NDF and ADF was significantly Pandlt;0.05)higher in Treat and SBR groups than CON. The N-retention as per cent of intake and absorbed-N was significantly Pandlt;0.001 higher in Treat and SBR groups than CON. The Ca and P retention gd-1 was significantly Pandlt;0.001 higher in SBR group followed by Treat and CON groups. The intake gd-1 and density % of DCP and TDN were significantly Pandlt;0.001 higher in SBR group followed by Treat and CON groups. Thus, it can be concluded that supplementation of the customised supplement (@ 0.25% of BW) to CON diet significantly improved the voluntary feed intake and nutrient metabolism in crossbred calves.

Association between aflatoxin-albumin adduct levels and tortilla consumption in Guatemalan adults.

Aflatoxin B1 (AFB1) is a known human hepatocarcinogen and a recent study reported elevated AFB1 levels, measured by serum albumin biomarkers, among Guatemalan adults. While AFB1 can contaminate a variety of foodstuffs, including maize, Guatemala's main dietary staple, the relationship of maize intake to serum AFB1-albumin adducts levels in Guatemala has not been previously examined. As a result, a cross-sectional study was conducted among 461 Guatemalan adults living in five geographically distinct departments of the country. Participants provided a serum sample and completed a semi-quantitative food frequency questionnaire and a sociodemographic questionnaire. Multiple linear regression analysis was used to estimate the least square means (LSQ) and 95% confidence intervals (95% CI) of log-transformed AFB1-albumin adducts by quintiles of maize consumption in crude and adjusted models. Additionally, analyses of tortilla consumption and levels of maize processing were conducted. The median maize intake was 344.3 g per day [Interquartile Range (IQR): 252.2, 500.8], and the median serum AFB1-albumin adduct level was 8.4 pg/mg albumin (IQR: 3.8, 22.3). In adjusted analyses, there was no association between overall maize consumption and serum AFB1-albumin levels. However, there was a statistically significant association between tortilla consumption and AFB1-albumin levels (ptrend = 0.01). The LSM of AFB1-albumin was higher in the highest quintile of tortilla consumption compared to the lowest quintile [LSM:9.03 95%CI: 7.03,11.70 vs 6.23, 95%CI: 4.95,8.17, respectively]. These findings indicate that tortilla may be an important source of AFB1 exposure in the Guatemalan population. Therefore, efforts to control or mitigate AFB1 levels in contaminated maize used for tortillas may reduce overall exposure in this population.

The effectiveness of regulatory maximum levels for fumonisin mycotoxins in commercial and subsistence maize crops in South Africa

The fumonisins are carcinogenic mycotoxins that have been implicated in various adverse human health effects. Recently, the Codex Alimentarius Commission set maximum levels (MLs) for fumonisin mycotoxins at 4000 μg/kg for raw maize and 2000 μg/kg for maize flour and maize meal and these have been incorporated into South African health regulations. The MLs are intended to be health protective such that fumonisin exposures will be below the provisional maximum tolerable daily intake (PMTDI) of fumonisin of 2 μg/kg body weight/day set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). South Africa has an extensive commercial maize farming industry as well as a large subsistence farming population reliant on home-grown maize. The available data on fumonisin contamination levels indicates that these MLs are readily met by the commercial crop. However, the situation in subsistence farming areas such as in the Eastern Cape Province region is of concern. The daily consumption of large amounts of highly fumonisin-contaminated home-grown maize is of relevance mainly due to rudimentary milling, which is not subject to the reduction in mycotoxin contamination associated with commercial milling. Analysis of historical fumonisin data from the Eastern Cape region indicates that approximately 12.8% of raw maize and 25% of the rural locally produced flour would not meet the respective MLs of 4000 μg/kg ML and 2000 μg/kg. Further analysis shows that given the high maize intake levels of this population, only prohibitively low MLs for raw maize of around 100–300 μg/kg would be health protective for different age groups in this area. Based on this analysis, the lowering of fumonisin exposure in subsistence farmers requires an integrated approach and cannot be achieved purely by regulatory means.

Post-harvest interventions decrease aflatoxin and fumonisin contamination in maize and subsequent dietary exposure in Tanzanian infants: a cluster randomised-controlled trial

A cluster randomised controlled trial was performed in three agro-ecological zones of Tanzania to evaluate the effectiveness of locally available post-harvest mitigation strategies in preventing and reducing aflatoxin and fumonisin contamination in maize. A total of 300 children, each from one household, were randomly selected from 30 villages (intervention: n=15). The mitigation strategies focused on hand sorting (prior to storage and use), drying maize on mat/raised platforms, proper sun drying, application of storage insecticides and de-hulling before milling. Maize sample was collected from each household at harvest (baseline) and six months after harvest. Maize intake by each child, estimated using the 24 h dietary recall technique and its body weight measured using standard procedures were taken at six months after harvest. Aflatoxins and fumonisins in the maize samples were determined using HPLC. Follow-up (six month after harvest) data were available for 261 of the 300 households (intervention: n=136). Mean concentration of aflatoxins, or fumonisins was significantly (P<0.05) lower in the intervention than in the control group: intervention effects: μg/kg (95% confidence interval (CI)) -4.9 (-7.3,-2.5), and -405, (-647,-162), respectively. The difference corresponds to 83 and 70% for aflatoxins, and fumonisins, respectively. At the end of the intervention, aflatoxin and fumonisin estimated mean intakes were lower in the intervention than in the control group by 78 and 65%, respectively. Six months after harvest, prevalence of underweight in the intervention group was 6.7% lower (P=0.014) than in the control group. Mean weight-for-age Z-score difference between the groups was 0.57 (95% CI; 0.16,-0.98;P=0.007). Post-harvest practices are effective in preventing and reducing aflatoxin and fumonisin contamination in maize and subsequent dietary exposure to infants. The interventions may be applied in these and other communities with similar environmental conditions or agricultural practices that favour production of aflatoxin and fumonisins in food crops. The trial was registered atClinicalTrials.gov identifier: NCT02438774.

Existe tendencia estacional en las anomalías del tubo neural en Guatemala?

Antecedentes: Las anomalías del tubo neural son muy frecuentes en Guatemala. Una mayor frecuencia se observa en el altiplano guatemalteco, con mayor concentración de población indígena y con mayor depauperación económica. Observaciones de especialistas indican que en el primer semestre del año son mucho más frecuentes que en el segundo. Estas observaciones señalan que algo existe en el ambiente, probablemente en el ambiente alimentario, relacionado con el consumo de maíz, base dietética del guatemalteco. En el grano de este cereal, existen fumomisinas (micotoxinas producidas por hongos) en gran cantidad, que tienen un efecto inhibidor de la captación celular de ácido fólico, micronutriente íntimamente relacionado con el cierre temprano del tubo neural. Objetivo: Demostrar si es cierto que existe mayor frecuencia de anomalías del tubo neural en Guatemala en el primer semestre del año que en el segundo, principalmente en los denominados meses de verano. Sugerir hipótesis futuras que expliquen este comportamiento epidemiológico. Metodología: Estudio descriptivo-analítico retrospectivo en la Unidad de Espina Bífida del Hospital General San Juan de Dios y en las 8 áreas geoeconómicas de Guatemala, analizando una sola variable: La fecha de nacimiento de niños y niñas que presentaron anomalías del tubo neural de diferente tipo. Resultados: Se demuestra que en efecto las anomalías del tubo neural son más frecuentes en el primer semestre del año que en el segundo. Principalmente en los meses de marzo-abril. Y que ocurren con menos frecuencia en el segundo semestre. Estos datos se podrían vincular con el consumo dietético de maíz, grano que también tiene diferencias estacionales en cuanto a su producción, almacenamiento, preparación y consumo. Conclusiones: Los hallazgos encontrados sugieren que las anomalías del tubo neural son más frecuentes en el período estacional conocido como verano en Guatemala. Lo que hace suponer que algo existe en el ambiente, principalmente en el consumo de maíz, que diversas investigaciones señalan que contiene concentraciones elevadas de fumonisinas, micotoxinas producidas por hongos y que son potentes inhibidores de la captación celular de ácido fólico.

Provitamin A-biofortified maize consumption increases serum xanthophylls and 13C-natural abundance of retinol in Zambian children.

Plants that undergo C4 photosynthesis, such as maize, are enriched in the stable isotope of carbon (13C) compared with other dietary plants and foods. Consumption of maize that has been biofortified to contain elevated levels of provitamin A carotenoids (orange maize) increased the abundance of 13C in serum retinol of Mongolian gerbils. We evaluated this method in humans to determine if it has potential for further use in intervention effectiveness studies. A random subset of samples from a two-month randomized controlled feeding trial of rural three- to five-year old Zambian children were used to determine the impact of orange maize intake on serum carotenoid concentrations ( n = 88) and 13C-natural abundance in serum retinol ( n = 77). Concentrations of β-cryptoxanthin (a xanthophyll provitamin A carotenoid) and the dihydroxy xanthophylls lutein and zeaxanthin, which do not have vitamin A activity, were elevated in children consuming orange maize compared with those consuming a white maize control ( P < 0.001), while β-carotene was not different ( P > 0.3). Furthermore, 13C natural abundance was higher after two months' intervention in the orange maize group compared with the white maize group ( P = 0.049). Predictions made from equations developed in the aforementioned gerbil study estimated that maize provided 11% (2-21%, 95% confidence interval) of the recent dietary vitamin A to these children. These results demonstrate that orange maize is efficacious at providing retinol to the vitamin A pool in children through provitamin A carotenoids, as monitored by the change in 13C enrichment, which was not reflected in serum β-carotene concentrations. Further effectiveness studies in countries who have adopted orange maize should consider determining differences in retinol 13C-enrichment among target groups in addition to profiling serum xanthophyll carotenoids with specific emphasis on zeaxanthin. Impact statement Maize biofortified with provitamin A carotenoids (orange) has been released in some African markets. Responsive and sensitive methods to evaluate dissemination effectiveness are needed. This study investigated methods to evaluate effectiveness of orange maize consumption using serum from Zambian children fed orange maize for two months. Many varieties of orange maize contain higher amounts of the xanthophyll carotenoids in addition to β-carotene compared with typical varieties. This study uniquely showed higher concentrations of the maize xanthophylls lutein, zeaxanthin, and β-cryptoxanthin in children who consumed orange maize compared with white. Furthermore, maize is a C4 plant and is therefore naturally enriched with 13C. Higher 13C was detected in the serum retinol of the orange maize consumers with no change in serum β-carotene concentration suggesting preferential bioconversion to retinol. The combined analyses of serum zeaxanthin specifically and 13C-natural abundance of retinol could prove useful in effectiveness studies between orange maize adopters and non-adopters.

Risk of Exposure to Multiple Mycotoxins from Maize-Based Complementary Foods in Tanzania.

This study estimated exposure to multiple mycotoxins in 249 infants aged between 6 and 12 months in three agro-ecological zones of Tanzania. Maize-based complementary food intakes were estimated using two 24 h dietary recalls. Using @Risk software, probabilistic exposure assessment was conducted by modeling maize intake data (kg/kg body weight/day) with previously determined multiple mycotoxin (except for ochratoxin A (OTA) and zearalenone (ZEA), present in only a few samples) contamination data (μg/kg) in maize. Maize intakes ranged from 0.13 to 185 g/child/day (average = 59 ± 36 g/child/day). The estimated mean exposures were higher for aflatoxins (6-fold), fumonisins (3-fold), and deoxynivalenol (2-fold) than health-based guidance values of 0.017 ng/kg body weight/day, 2 μg/kg body weight/day, and 1 μg/kg body weight/day, respectively. The population at risk of exposures above the limits of health concern ranged from 12% for HT-2 toxin through 35% for deoxynivalenol to 100% for aflatoxins. The exposure varied among the agro-ecological zones. Strategies targeting multiple mycotoxins in maize are urgently needed to minimize exposures in Tanzania.

Short-Term Daily Consumption of Provitamin A Carotenoid–Biofortified Maize Has Limited Impact on Breast Milk Retinol Concentrations in Zambian Women Enrolled in a Randomized Controlled Feeding Trial

Background: Provitamin A carotenoid–biofortified maize is a conventionally bred staple crop designed to help prevent vitamin A deficiency. Lactating women are a potential target group, because regularly eating biofortified maize may increase vitamin A in breast milk—a critical source of vitamin A for breastfeeding infants.Objective: We assessed whether daily consumption of biofortified orange maize would increase the retinol concentration in the breast milk of Zambian women.Methods: Lactating women (n = 149) were randomly assigned to receive orange maize delivering 600 μg retinol equivalents (REs)/d as carotenoid plus placebo (OM), low-carotenoid white maize plus 600 μg REs/d as retinyl palmitate (VA), or white maize plus placebo (WM). Boiled maize (287 g dry weight/d) was served as 2 meals/d, 6 d/wk for 3 wk. We measured initial and final breast milk plasma retinol and β-carotene concentrations, and plasma inflammatory protein concentrations.Results: Groups were comparable at enrollment, with an overall geometric mean milk retinol concentration of 0.95 μmol/L (95% CI: 0.86, 1.05 μmol/L); 56% of samples had milk retinol <1.05 μmol/L. Median capsule and maize intake was 97% and 258 g dry weight/d, respectively. Final milk β-carotene did not vary across groups (P = 0.76). Geometric mean (95% CI) milk retinol concentration tended to be higher in the OM [1.15 μmol/L (0.96, 1.39 μmol/L)] and VA [1.17 μmol/L (0.99, 1.38 μmol/L)] groups than in the WM group [0.91 μmol/L (0.72, 1.14 μmol/L); P = 0.13], and the proportion of women with milk retinol <1.05 μmol/L was 52.1%, 42.9%, and 36.7% in the WM, OM, and VA groups, respectively (P-trend = 0.16).Conclusions: Daily biofortified maize consumption did not increase mean milk retinol concentration in lactating Zambian women; however, there was a plausible downward trend in the risk of low milk retinol across intervention groups. This trial was registered at clinicaltrials.gov as NCT01922713.