Reduced foodborne toxin exposure is a benefit of improving dietary diversity

Fifty Years of Aflatoxin Research in Qidong, China: A Celebration of Team Science to Improve Public Health

The Qidong Liver Cancer Institute (QDLCI) and the Qidong Cancer Registry were established in 1972 with input from doctors, other medical practitioners, and non-medical investigators arriving from urban centers such as Shanghai and Nanjing. Medical teams were established to quantify the extent of primary liver cancer in Qidong, a corn-growing peninsula on the north side of the Yangtze River. High rates of liver cancer were documented and linked to several etiologic agents, including aflatoxins. Local corn, the primary dietary staple, was found to be consistently contaminated with high levels of aflatoxins, and bioassays using this corn established its carcinogenicity in ducks and rats. Observational studies noted a positive association between levels of aflatoxin in corn and incidence of liver cancer across townships. Biomarker studies measuring aflatoxin B1 and its metabolite aflatoxin M1 in biofluids reflected the exposures. Approaches to decontamination of corn from aflatoxins were also studied. In 1993, investigators from Johns Hopkins University were invited to visit the QDLCI to discuss chemoprevention studies in some townships. A series of placebo-controlled clinical trials were conducted using oltipraz (a repurposed drug), chlorophyllin (an over-the-counter drug), and beverages prepared from 3-day-old broccoli sprouts (rich in the precursor phytochemical for sulforaphane). Modulation of biomarkers of aflatoxin DNA and albumin adducts established proof of principle for the efficacy of these agents in enhancing aflatoxin detoxication. Serendipitously, by 2012, aflatoxin exposures quantified using biomarker measurements documented a many hundred-fold reduction. In turn, the Cancer Registry documents that the age-standardized incidence rate of liver cancer is now 75% lower than that seen in the 1970s. This reduction is seen in Qidongese who have never received the hepatitis B vaccination. Aflatoxin mitigation driven by economic changes switched the dietary staple of contaminated corn to rice coupled with subsequent dietary diversity leading to lower aflatoxin exposures. This 50-year effort to understand the etiology of liver cancer in Qidong provides the strongest evidence for aflatoxin mitigation as a public health strategy for reducing liver cancer burden in exposed, high-risk populations. Also highlighted are the challenges and successes of international team science to solve pressing public health issues.

Exploring Multidimensional and Within-Food Group Diversity for Diet Quality and Long-Term Health in High-Income Countries

Dietary diversity is a crucial component of healthy eating patterns because it ensures nutritional adequacy. Yet, concerns have been raised about the potential risks of its increase, which may reflect excessive consumption of unhealthy foods and higher obesity or cardiometabolic risk, particularly in high-income countries. However, the links between dietary diversity and different health outcomes remain inconclusive because of methodological differences in assessing dietary diversity. Numerous studies, mostly cross-sectional, have assessed dietary diversity using different indicators usually based only on the number of foods or food groups consumed. In this perspective, we emphasize that dietary diversity is a multidimensional concept encompassing the number of foods in the diet (food coverage) but also their relative proportions (food evenness) and the nutritional dissimilarity of foods consumed over time (food complementarity). Consequently, a comprehensive assessment of dietary diversity reflecting all its dimensions, both between and within-food groups, is needed to determine the optimal level of complementarity between and within-food groups required to improve health and diet quality. Moreover, given the prevailing context of abundant highly processed and energy-dense foods in high-income countries, promoting dietary diversity should prioritize nutrient-dense food groups. Until recently, within-food group diversity has received limited attention in research and public health recommendations. Still, it may play a role in improving diet quality and long-term health. This perspective aims to clarify the concept of dietary diversity and suggest research avenues that should be explored to better understand its associations with nutritional adequacy and health among adults in high-income countries.

Children's cognitive impairment associated with cassava cyanide in Democratic Republic of the Congo: Burden of disease

Worldwide, tens of millions of children rely on cassava as a dietary staple throughout their formative years of brain and behavioral development. Recently, it was discovered that cassava cyanide can impair children's neurocognitive development at relatively low exposures. We revisited the World Health Organization's foodborne disease burden estimate of cassava cyanide, focusing on the new health endpoint of children's cognitive impairment in Democratic Republic of the Congo (DRC). The loss of Intelligence Quotient (IQ) scores was used to measure the endpoint of cognitive impairment caused by cassava cyanide exposure, which was estimated based on the concentration-effect relationship between children's IQ scores and cyanide concentrations in flour. We estimated the burden of intellectual disability (ID) associated with cassava cyanide exposure in terms of disability-adjusted life years (DALYs). The median content of cyanide in cassava samples collected from DRC was 12.5 mg/kg, causing a median decrement to children's IQ of 2.37 points. The estimated number of children with ID associated with cassava cyanide exposure was 1,643 cases, although 1,567 of these cases (95%) were mild ID. The burden of cognitive impairment attributable to cassava cyanide in DRC alone was 13,862 DALYs per 100,000 children, or 3.01 million for all children under age 5. The results of the study, showing a significant burden of cassava cyanide-related cognitive impairment in children even at relatively low doses, can contribute to the implementation of cost-effective interventions to make cassava consumption safer for children in high-risk rural areas of DRC.

Functional analyses of single nucleotide polymorphic variants of the DNA glycosylase NEIL1 in sub-Saharan African populations

Nei-like glycosylase 1 (NEIL1) is a DNA repair enzyme that initiates the base excision repair (BER) pathway to cleanse the human genome of damage. The substrate specificity of NEIL1 includes several common base modifications formed under oxidative stress conditions, as well as the imidazole ring open adducts that are induced by alkylating agents following initial modification at N7 guanine. An example of the latter is the persistent and mutagenic 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxyaflatoxin B1 (AFB1-FapyGua) adduct, resulting from the alkylating agent aflatoxin B1 (AFB1) exo-8-9-epoxide. Naturally occurring single nucleotide polymorphic (SNP) variants of NEIL1 are hypothesized to be associated with an increased risk for development of early-onset hepatocellular carcinoma (HCC), especially in environments with high exposures to aflatoxins and chronic inflammation from viral infections and alcohol consumption. Given that AFB1 exposures and hepatitis B viral (HBV) infections represent a major problem in the developing countries of sub-Saharan Africa, it is pertinent to study SNP NEIL1 variants that are present in this geographic region. In this investigation, we characterized the three most common NEIL1 variants found in this region: P321A, R323G, and I182M. Biochemical analyses were conducted to determine the proficiencies of these variants in initiating the repair of DNA lesions. Our data show that damage recognition and excision activities of P321A and R323G were near that of wild-type (WT) NEIL1 for both thymine glycol (ThyGly) and AFB1-FapyGua. The substrate specificities of these variants with respect to various oxidatively-induced base lesions were also similar to that of WT. In contrast, the I182M variant was unstable, such that it precipitated under a variety of conditions and underwent rapid inactivation at a biologically relevant temperature, with partial stabilization being observed in the presence of undamaged DNA. This study provides insight regarding the potential increased risk for early-onset HCC in human populations carrying the NEIL1 I182M variant.

Mycotoxins Exposure of Lactating Women and Its Relationship with Dietary and Pre/Post-Harvest Practices in Rural Ethiopia

Mycotoxins can be transferred to breast milk during lactation. Hence, the presence of multiple mycotoxins (aflatoxins B1, B2, G1, G2, and M1, alpha and beta zearalanol, deoxynivalenol, fumonisins B1, B2, B3, and hydrolyzed B1, nivalenol, ochratoxin A, ochratoxin alpha, and zearalenone) in breast milk samples was assessed in our study. Furthermore, the relationship between total fumonisins and pre/post-harvest and the women's dietary practices was examined. Liquid chromatography coupled with tandem mass spectrometry was used to analyze the 16 mycotoxins. An adjusted censored regression model was fitted to identify predictors of mycotoxins, i.e., total fumonisins. We detected only fumonisin B2 (15% of the samples) and fumonisin B3 (9% of the samples) while fumonisin B1 and nivalenol were detected only in a single breast milk sample. No association between total fumonisins and pre/post-harvest and dietary practices was found (p < 0.05). The overall exposure to mycotoxins was low in the studied women, although fumonisins contamination was not negligible. Moreover, the recorded total fumonisins was not associated with any of the pre/post-harvest and dietary practices. Therefore, to better identify predictors of fumonisin contamination in breast milk, longitudinal studies with food samples in addition to breast milk samples and with larger sample sizes are needed for the future.

Mycotoxins were not associated with environmental enteropathy in a cohort of Tanzanian children

Enteropathy is a pathophysiological condition characterized by decreased intestinal barrier function and absorption. Past studies have hypothesized that mycotoxins might impair children's growth by causing intestinal enteropathy, including interactions between mycotoxins and pathogens. We investigated the association of two mycotoxins, aflatoxin B1 (AFB1 ) and fumonisin B1 (FB1 ), independently and in conjunction with microbial pathogens, with fecal biomarkers of environmental enteropathy in children. As part of a larger MAL-ED study, 196 children were recruited in Haydom, Tanzania, and followed for the first 36 months of life. The gut inflammation biomarkers myeloperoxidase (MPO), neopterin (NEO), and alpha-1-antitrypsin (A1AT) were analyzed in stool samples at 24 months; with mean concentrations 5332.5 ng/L MPO, 807.2 nmol/L NEO, and 0.18 mg/g A1AT. Forty-eight children were measured for AFB1 -lys, with a mean of 5.30 (95% CI: 3.93-6.66) pg/mg albumin; and 87 were measured for FB1 , with a mean of 1.25 (95% CI: 0.72-1.76) ng/ml urine. Although the pathogens adenovirus and Campylobacter were associated with A1AT (p = 0.049) and NEO (p = 0.004), respectively, no association was observed between aflatoxin (MPO, p = 0.30; NEO, p = 0.08; A1AT, p = 0.24) or fumonisin (MPO, p = 0.38; NEO, p = 0.65; A1AT, p = 0.20) exposure and any gut inflammation biomarkers; nor were interactive effects found between mycotoxins and pathogens in contributing to intestinal enteropathy in this cohort. Although further studies are needed to confirm these results, it is possible that mycotoxins contribute to child growth impairment via mechanisms other than disrupting children's intestinal function.

Aflatoxin Contamination of Maize, Groundnut, and Sorghum Grown in Burkina Faso, Mali, and Niger and Aflatoxin Exposure Assessment

Aflatoxin contamination of staple crops by Aspergillus flavus and closely related fungi is common across the Sahel region of Africa. Aflatoxins in maize, groundnut, and sorghum collected at harvest or from farmers' stores within two weeks of harvest from Burkina Faso, Mali, and Niger were quantified. Thereafter, aflatoxin exposure values were assessed using per capita consumption rates of those crops. Mean aflatoxin concentrations in maize were high, 128, 517, and 659 µg/kg in Mali, Burkina Faso, and Niger, respectively. The estimated probable daily intake (PDI) of aflatoxins from maize ranged from 6 to 69, 29 to 432, and 310 to 2100 ng/kg bw/day in Mali, Burkina Faso, and Niger, respectively. Similarly, mean aflatoxin concentrations in sorghum were high, 76 and 259 µg/kg in Mali and Niger, respectively, with an estimated PDI of 2-133 and 706-2221. For groundnut, mean aflatoxin concentrations were 115, 277, and 628 µg/kg in Mali, Burkina Faso, and Niger, respectively. Aflatoxin exposure values were high with an estimated 9, 28, and 126 liver cancer cases/100,000 persons/year in Mali, Burkina Faso, and Niger, respectively. Several samples were extremely unsafe, exceeding manyfold regulatory levels of diverse countries (up to 2000 times more). Urgent attention is needed across the Sahel for integrated aflatoxin management for public health protection, food and nutrition security, and access to trade opportunities.

Mycotoxin Regulatory Status in Africa: A Decade of Weak Institutional Efforts

Food safety problems are a major hindrance to achieving food security, trade, and healthy living in Africa. Fungi and their secondary metabolites, known as mycotoxins, represent an important concern in this regard. Attempts such as agricultural, storage, and processing practices, and creation of awareness to tackle the menace of fungi and mycotoxins have yielded measurable outcomes especially in developed countries, where there are comprehensive mycotoxin legislations and enforcement schemes. Conversely, most African countries do not have mycotoxin regulatory limits and even when available, are only applied for international trade. Factors such as food insecurity, public ignorance, climate change, poor infrastructure, poor research funding, incorrect prioritization of resources, and nonchalant attitudes that exist among governmental organisations and other stakeholders further complicate the situation. In the present review, we discuss the status of mycotoxin regulation in Africa, with emphasis on the impact of weak mycotoxin legislations and enforcement on African trade, agriculture, and health. Furthermore, we discuss the factors limiting the establishment and control of mycotoxins in the region.

Urinary Aflatoxin M1 Concentration and Its Determinants in School-Age Children in Southern Ethiopia

Aflatoxins are mycotoxins that can contaminate grains, legumes, and oil seeds. These toxic compounds are an especially serious problem in tropical and sub-tropical climates. The objective of this study was to raise awareness of aflatoxin exposure among primary school children in Shebedino woreda, southern Ethiopia, by measuring urinary aflatoxin M1 (AFM1). The study employed a cross-sectional design and systematic random sampling of children from eight schools in the district. The mean ± SD age of the children was 9.0 ± 1.8 years. Most (84.6%) households were food insecure with 17.9% severely food insecure. Urinary AFM1 was detected in more than 93% of the children. The median [IQR] concentration of AFM1/Creat was 480 [203, 1085] pg/mg. Based on a multiple regression analysis: DDS, consumption of haricot bean or milk, source of drinking water, maternal education, and household food insecurity access scale scores were significantly associated with urinary AFM1/Creat. In conclusion, a high prevalence of urinary AFM1 was observed in this study. However, the relation between AFM1 and dietary intake was analyzed based on self-reported dietary data; hence, all of the staple foods as well as animal feeds in the study area should be assessed for aflatoxin contamination.

Dietary determinants of aflatoxin B1-lysine adduct among infants in Nepal

BACKGROUND

Aflatoxins are mycotoxins produced by naturally occurring fungi on food, and aflatoxin B₁ (AFB₁) is carcinogenic, immunotoxic and hepatotoxic. This study assesses the relationship between AFB₁ in Nepali infants at 12 months of age and their diet at 9 and 12 months of age.

METHODS

The study used data collected from 1329 infants enrolled in the AflaCohort Study. Aflatoxin exposure was assessed at 12 months using serum AFB₁-lysine pg/mg albumin biomarker measured using high performance liquid chromatography-fluorescent detection. Dietary data were collected using food frequency questionnaire. We conducted ordinary least squares and quantile regression analyses with backward elimination to assess lagged (9-month diet and 12-month AFB₁) and contemporaneous (12-month diet and 12-month AFB₁) associations.

RESULTS

Eighty-one percent of children at 12 months had detectable levels of serum AFB₁-lysine (geometric mean: 0.79 pg/mg albumin, 95% CI: 0.74-0.83). The levels ranged from 0.4 to 85 pg/mg albumin. Dietary diversity at 9 and 12 months were not associated with serum AFB₁-lysine levels. Consumption of fish and groundnuts at both 9 and 12 months and infant formula and cauliflower at 9 months were associated with higher serum AFB₁-lysine while consumption of bananas and mangoes at 12 months were negatively associated with serum AFB₁-lysine (p < 0.05).

CONCLUSIONS

High prevalence of detectable AFB₁-lysine among infants, and possible links to their dietary patterns argues for more urgent research into which foods in children's diets are most contaminated, and into optimal entry points in the food chain that would allow for effective actions to minimize exposure.

Lactic Acid Bacteria from African Fermented Cereal-Based Products: Potential Biological Control Agents for Mycotoxins in Kenya

Cereals play an important role in global food security. Data from the UN Food and Agriculture Organization projects increased consumption of cereals from 2.6 billion tonnes in 2017 to approximately 2.9 billion tonnes by 2027. However, cereals are prone to contamination by toxigenic fungi, which lead to mycotoxicosis. The current methods for mycotoxin control involve the use of chemical preservatives. However, there are concerns about the use of chemicals in food preservation due to their effects on the health, nutritional quality, and organoleptic properties of food. Therefore, alternative methods are needed that are affordable and simple to use. The fermentation technique is based on the use of microorganisms mainly to impart desirable sensory properties and shelf-life extension. The lactic acid bacteria (LAB) are generally regarded as safe (GRAS) due to their long history of application in food fermentation systems and ability to produce antimicrobial compounds (hydroxyl fatty acids, organic acids, phenyllactic acid, hydrogen peroxide, bacteriocins, and carbon dioxide) with a broad range of antifungal activity. Hence, LAB can inhibit the growth of mycotoxin-producing fungi, thereby preventing the production of mycotoxins. Fermentation is also an efficient technique for improving nutrient bioavailability and other functional properties of cereal-based products. This review seeks to provide evidence of the potential of LAB from African fermented cereal-based products as potential biological agents against mycotoxin-producing fungi.

Multiple mycotoxin exposure during pregnancy and risks of adverse birth outcomes: a prospective cohort study in rural Ethiopia

INTRODUCTION

Mycotoxin exposure during pregnancy has been associated with adverse birth outcomes in low- and middle-income countries. The evidence, however, is inconsistent and mainly limited to the assessment of a single mycotoxin. We assessed biomarkers of exposure to multiple mycotoxins during pregnancy and their associations with adverse birth outcomes in rural Ethiopia.

METHODS

We analyzed data from 579 pregnant women between 8 and 24 weeks of completed gestation enrolled in a prospective cohort study. Serum mycotoxin concentrations were determined using liquid chromatography coupled with tandem mass spectrometry. Multivariable linear probability models, adjusted for potential confounding factors and multiple comparisons, were fitted to assess the associations between mycotoxin exposure and small for gestational age and preterm birth. We applied principal component analysis to reduce the dimensionality of biomarker data from several taxonomic mycotoxin groups.

RESULTS

All pregnant women were co-exposed to at least five mycotoxins, and one pregnant woman was co-exposed to 27 mycotoxins. Fumonisins (FB), i.e., FB₂, FB₃, FB₁, and tenuazonic acid were the most frequently identified mycotoxins in 98.8, 95.3, 93.3, and 81.4% of the samples respectively. Deoxynivalenol was detected in 38.7%, nivalenol in 50.1%, ochratoxin α in 67.9%, and zearalenone in 50.9% of the serum samples. After adjustment, we found no statistically significant (all P ≥ 0.05) associations between mycotoxin exposures and birth outcomes.

CONCLUSIONS

Despite our study providing no evidence for relationships between mycotoxin biomarkers and adverse birth outcomes, our findings do indicate an extensive presence of multiple mycotoxin exposure among pregnant women. Public health policies and nutrition-sensitive interventions must ensure exposure to mycotoxins is reduced in rural Ethiopia.

Ethical considerations in the design and conduct of a cluster-randomised mycotoxin mitigation trial in Tanzania

Aflatoxins are fungal metabolites that commonly contaminate staple food crops in tropical regions. Acute aflatoxin consumption in very high concentration causes aflatoxicosis and acute liver failure, while chronic, moderate levels of intake cause hepatocellular carcinoma. The effects of frequent moderate- to high-level exposure during infancy, however, is less clearly understood. Half a billion people in low- and middle-income countries continue to be exposed to aflatoxins through dietary consumption, in part because of lack of enforcement of regulatory limits and few feasible long-term mitigation options in these settings. Several epidemiologic studies have shown an association between aflatoxin exposure in infants and young children and growth failure, but strong experimental evidence is lacking. The Mycotoxin Mitigation Trial conducted in Tanzania was a cluster-randomised trial to assess the effect of a reduced aflatoxin diet on linear growth. Prior to the design and implementation of this trial, a group of multi-disciplinary and multi-national scientists reviewed literature in biomedical, public health, environmental health ethics. In this paper we outline the most salient ethical questions and dilemmas in the potential conduct of such a study and describe the ethical precedents and principles that informed our decision-making processes and ultimate study protocol.

Spatiotemporal assessment of post-harvest mycotoxin contamination in rural North Indian food systems

The spatiotemporal trends in aflatoxin B1 (AFB1), fumonisin B1 (FB1), and deoxynivalenol (DON) accumulation were analyzed in a range of food commodities (maize, groundnut, pearl millet, rice, and wheat) in village settings in Unnao, Uttar Pradesh, India. Samples (n = 1549) were collected across six communities and six time points spanning a calendar year and were analyzed for mycotoxins using enzyme-linked immunosorbent assays. AFB1 and FB1 were common across surveyed villages, with moderate to high detection rates (45-75%) observed across commodities. AFB1 levels in maize and groundnuts and FB1 levels in maize and pearl millet frequently exceeded regulatory threshold levels of 15 μg/kg (AFB1) and 2 μg/g (FB1). DON was analyzed in wheat, with 3% of samples yielding detectable levels and none exceeding 1 μg/g. In rice, AFB1 levels were highest in the bran and husk and lower in the kernel. Commodity type significantly influenced AFB1 detection status, while commodity type, season, and visual quality influenced samples' legal status. Storage characteristics and household socioeconomic status indicators did not have significant effects on contamination. No significant effects of any variables on FB1 detection or legal status were observed. Data on mycotoxin contamination, combined with data on local dietary intake, were used to estimate spatiotemporal mycotoxin exposure profiles. Estimated seasonal per capita exposure levels for AFB1 (5.4-39.3 ng/kg body weight/day) and FB1 (~0-2.4 μg/kg body weight/day) exceeded provisional maximum tolerable daily intake levels (1 ng/kg body weight/day for AFB1 and 2 μg/kg body weight/day for FB1) in some seasons and locations. This study demonstrates substantial dietary mycotoxin exposure risk in Unnao food systems and serves as an evidentiary foundation for participatory food safety intervention in the region.

Cost-effectiveness of a wetting method intervention to reduce cassava cyanide-related cognitive impairment in children

Cassava cyanide-related neurocognitive impairment may persist for years in Central African children who rely on cassava as a dietary staple. In the Democratic Republic of the Congo, a cassava processing method, the 'wetting method', reduced cyanide in cassava, prevented konzo, and proved a cost-effective intervention to improve children's cognitive development. Scaling up use of the wetting method may help prevent neurocognitive impairment in millions of at-risk children in sub-Saharan Africa.

Mycotoxins Affecting Animals, Foods, Humans, and Plants: Types, Occurrence, Toxicities, Action Mechanisms, Prevention, and Detoxification Strategies-A Revisit

Mycotoxins are produced by fungi and are known to be toxic to humans and animals. Common mycotoxins include aflatoxins, ochratoxins, zearalenone, patulin, sterigmatocystin, citrinin, ergot alkaloids, deoxynivalenol, fumonisins, trichothecenes, Alternaria toxins, tremorgenic mycotoxins, fusarins, 3-nitropropionic acid, cyclochlorotine, sporidesmin, etc. These mycotoxins can pose several health risks to both animals and humans, including death. As several mycotoxins simultaneously occur in nature, especially in foods and feeds, the detoxification and/or total removal of mycotoxins remains challenging. Moreover, given that the volume of scientific literature regarding mycotoxins is steadily on the rise, there is need for continuous synthesis of the body of knowledge. To supplement existing information, knowledge of mycotoxins affecting animals, foods, humans, and plants, with more focus on types, toxicity, and prevention measures, including strategies employed in detoxification and removal, were revisited in this work. Our synthesis revealed that mycotoxin decontamination, control, and detoxification strategies cut across pre-and post-harvest preventive measures. In particular, pre-harvest measures can include good agricultural practices, fertilization/irrigation, crop rotation, using resistant varieties of crops, avoiding insect damage, early harvesting, maintaining adequate humidity, and removing debris from the preceding harvests. On the other hand, post-harvest measures can include processing, chemical, biological, and physical measures. Additionally, chemical-based methods and other emerging strategies for mycotoxin detoxification can involve the usage of chitosan, ozone, nanoparticles, and plant extracts.

Modelling bioactivities of combinations of whole extracts of edibles with a simplified theoretical framework reveals the statistical role of molecular diversity and system complexity in their mode of action and their nearly certain safety

Network pharmacology and polypharmacology are emerging as novel drug discovery paradigms. The many discovery, safety and regulatory issues they raise may become tractable with polypharmacological combinations of natural compounds found in whole extracts of edible and mixes thereof. The primary goal of this work is to get general insights underlying the innocuity and the emergence of beneficial and toxic activities of combinations of many compounds in general and of edibles in particular. A simplified model of compounds’ interactions with an organism and of their desired and undesired effects is constructed by considering the departure from equilibrium of interconnected biological features. This model allows to compute the scaling of the probability of significant effects relative to nutritional diversity, organism complexity and synergy resulting from mixing compounds and edibles. It allows also to characterize massive indirect perturbation mode of action drugs as a potential novel multi-compound-multi-target pharmaceutical class, coined Ediceuticals when based on edibles. Their mode of action may readily target differentially organisms’ system robustness as such based on differential complexity for discovering nearly certainly safe novel antimicrobials, antiviral and anti-cancer treatments. This very general model provides also a theoretical framework to several pharmaceutical and nutritional observations. In particular, it characterizes two classes of undesirable effects of drugs, and may question the interpretation of undesirable effects in healthy subjects. It also formalizes nutritional diversity as such as a novel statistical supra-chemical parameter that may contribute to guide nutritional health intervention. Finally, it is to be noted that a similar formalism may be further applicable to model whole ecosystems in general.

Estimates of dietary quality in infants and young children (6-23 mo): Evidence from demographic and health surveys of 49 low- and middle-income countries

OBJECTIVE

Dietary diversity in early life can prevent all forms of malnutrition and can establish a healthier dietary pattern for later life. However, multicountry national estimates are lacking. The aim of this study was to estimate the proportion of infants and young children (IYC) meeting the minimum dietary diversity (MMD), minimum meal frequency (MMF), and minimum acceptable diet (MAD).

METHODS

We calculated the proportion of IYC (6-23 mo of age) meeting the updated MDD, MMF, and MAD for 49 low- and middle-income countries. We calculated the proportion of IYC meeting the MDD by region, rural/urban residence, and wealth quintile. The proportion of stunting cases that would have been averted if 90% of the IYC met their MDD was estimated.

RESULTS

The proportion of IYC meeting MDD, MMF, and MAD was very low. Only 4 of 49 countries had >50% of IYC meeting MDD. The lowest MDD was for the sub-Saharan African region (18%) and the highest was for the Latin America and Caribbean (54%) region. Stark inequalities exist between countries, rural/urban residence, and wealth quintiles. A significant proportion (>11 million) of stunting cases could have been averted if ≥90% of IYC had met the MDD. MDD proportions increased with higher gross national income purchasing power parity, maternal literacy, and food supply diversity (P < 0.05).

CONCLUSIONS

Closing the gap in dietary inequalities between and within countries is urgently needed to prevent wider, long-term socioeconomic and health inequalities. Diet-quality targets should be set and monitored routinely to promote dietary diversity and prevent all forms of malnutrition.

Burden of disease associated with dietary exposure to carcinogenic aflatoxins in Portugal using human biomonitoring approach

Human biomonitoring is an important tool to assess human exposure to chemicals, contributing to describe trends of exposure over time and to identify population groups that could be under risk. Aflatoxins are genotoxic and carcinogenic food contaminants causing hepatocellular carcinoma, the third leading cause of cancer deaths worldwide. In Portugal, scarce data are available regarding exposure to aflatoxins and no previous study used human biomonitoring data to comprehensively characterize the associated burden of disease. 24 h urine and first-morning urine paired samples were collected by 94 participants and were analyzed by liquid chromatography-tandem mass spectrometry for the quantitative determination of aflatoxins (B₁, B₂, G₁, G₂ and M₁). Deterministic and probabilistic models were developed to assess the Portuguese exposure to aflatoxins and to estimate the health impact of this exposure, estimating the attributed Disability-Adjusted Life Years (DALYs). Aflatoxins were detected in a maximum of 13% (AFB₁), 16% (AFB₂), 1% (AFG₁), 2% (AFG₂) and 19% (AFM₁) of the urine samples. Data obtained through the probabilistic approach revealed an estimated mean probable daily intake of 13.43 ng/kg body weight per day resulting in 0.13 extra cases of hepatocellular carcinoma, corresponding to mean annual DALYs of 172.8 for the Portuguese population (10291027 inhabitants). The present study generated for the first time and within a human biomonitoring study, reliable and crucial data to characterize the burden associated to the exposure to aflatoxins of the Portuguese population. The obtained results constitute an imperative support to risk managers in the establishment of preventive policy measures that contribute to ensure public health protection.

Dietary determinants of aflatoxin B1-lysine adduct in pregnant women consuming a rice-dominated diet in Nepal

Background

Aflatoxins are found in diverse foods widely consumed worldwide. This study investigated the association between aflatoxin exposure and (a) consumption of specific foods, (b) dietary diversity (DD), and (c) seasonality.

Methods

Women enrolled in the AflaCohort Study in Banke, Nepal (n = 1648) were asked how often they ate certain food items in the past 7 days and 24 h. Serum aflatoxin B₁-lysine (AFB₁-lys) adduct levels, measured during pregnancy, were determined using high-performance liquid chromatography. Multivariable ordinary least squares and quantile regression models were used to examine incremental increases in AFB₁-lys adduct levels per frequency of food consumption and the relationship between DD, seasonality, and increases in AFB₁-lys adduct.

Results

Roughly 94% of women were exposed to aflatoxin (geometric mean 1.37 pg/mg). Women in the 30th, 50th, and 70th quantiles of aflatoxin exposure who reported one more occasion of maize consumption in the past week showed increases in AFB₁-lys adduct levels: 0.094, 0.112, and 0.109 pg/mg (p < 0.05, all). Women in the 30th, 50th, 70th, and 90th quantiles of exposure who reported one more occasion of groundnut consumption in the past week also showed increases in AFB₁-lys adduct levels: 0.058 (p < 0.001), 0.085 (p < 0.01), 0.133 (p < 0.001), and 0.133 (p < 0.001) pg/mg. Winter month recruitment was positively associated with AFB₁-lys adduct levels at all quantiles of aflatoxin exposure (range: 0.313–1.101 pg/mg, p < 0.001). DD was not predictive of aflatoxin exposure.

Conclusions

Our findings justify integrated approaches to aflatoxin reduction, including regulatory, agricultural, and food safety interventions across the value chain and at the household level.

Mechanisms underlying aflatoxin-associated mutagenesis - Implications in carcinogenesis

Chronic dietary exposure to aflatoxin B1 (AFB1), concomitant with hepatitis B infection is associated with a significant increased risk for hepatocellular carcinomas (HCCs) in people living in Southeast Asia and sub-Saharan Africa. Human exposures to AFB1 occur through the consumption of foods that are contaminated with pervasive molds, including Aspergillus flavus. Even though dietary exposures to aflatoxins constitute the second largest global environmental risk factor for cancer development, there are still significant questions concerning the molecular mechanisms driving carcinogenesis and what factors may modulate an individual's risk for HCC. The objective of this review is to summarize key discoveries that established the association of chronic inflammation (most commonly associated with hepatitis B viral (HBV) infection) and environmental exposures to aflatoxin with increased HCC risk. Special emphasis will be given to recent investigations that have: 1) refined the aflatoxin-associated mutagenic signature, 2) expanded the DNA repair mechanisms that limit mutagenesis via adduct removal prior to replication-induced mutagenesis, 3) implicated a specific DNA polymerase in the error-prone bypass and resulting mutagenesis, and 4) identified human polymorphic variants that may modulate individual susceptibility to aflatoxin-induced cancers. Collectively, these investigations revealed that specific sequence contexts are differentially resistant against, or prone to, aflatoxin-induced mutagenesis and that these associations are remarkably similar between in vitro and in vivo analyses. These recent investigations also established DNA polymerase ζ as the major polymerase that confers the G to T transversion signature. Additionally, although the nucleotide excision repair (NER) pathway has been previously shown to repair aflatoxin-induced DNA adducts, recent murine data demonstrated that NEIL1-initiated base excision repair was significantly more important than NER relative to the removal of the highly mutagenic AFB1-Fapy-dG adducts. These data suggest that inactivating polymorphic variants of NEIL1 could be a potential driver of HCCs in aflatoxin-exposed populations.

Qidong: a crucible for studies on liver cancer etiology and prevention

Qidong (Jiangsu, China) has been of interest to cancer epidemiologists and biologists because, until recently, it was an endemic area for liver cancer, having amongst the highest incidence rates in the world. The establishment of the Qidong Cancer Registry together with the Qidong Liver Cancer Institute in 1972 has charted the patterns of liver cancer incidence and mortality in a stable population throughout a period of enormous economic, social, and environmental changes as well as of improvements in health care delivery. Updated incidence trends in Qidong are described. Notably, the China age-standardized incidence rate for liver cancer has dropped by over 50% in the past several decades. Molecular epidemiologic and genomic deep sequencing studies have affirmed that infection with hepatitis B virus as well as dietary exposure to aflatoxins through contamination of dietary staples such as corn, and to microcystins – blue-green algal toxins found in ditch and pond water – were likely important etiologic factors that account for the high incidence of liver cancer in this region. Public health initiatives to facilitate universal vaccination of newborns against HBV and to improve drinking water sources in this rural area, as well as economic and social mandates serendipitously facilitating dietary diversity, have led to precipitous declines in exposures to these etiologic factors, concomitantly driving substantive declines in the liver cancer incidence seen now in Qidong. In this regard, Qidong serves as a template for the global impact that a package of intervention strategies may exert on cancer burden.

Mycotoxin management in a developing country context: A critical review of strategies aimed at decreasing dietary exposure to mycotoxins in Zimbabwe

Mycotoxins are unavoidable environmental contaminants, which are found throughout the food chain, particularly in cereals. Mycotoxin management is not effective in developing countries, such as Zimbabwe, due to resource constraints, yet human health risk is evident. Various practical mitigation strategies that can be employed to decrease human dietary exposure to mycotoxins as a means of preliminary steps towards risk management are discussed. These strategies were stratified into two categories. First, crop/commodity-centred strategies, mainly the pre-harvest actions of cultivar selection, bio-control, as well as good agricultural practices (GAP), and the post-harvest actions including timeous harvesting, appropriate drying and storage technologies, are elaborated making use of hazard analysis critical control points (HACCP) principles. The role of legislation is also explored as a crop/commodity centred mitigation strategy. Second, human-centred strategies anchored on dietary diversity and the use of socio-cultural approaches as a direct means of reducing mycotoxin exposure are discussed. Finally, an integrated science-based mycotoxin management strategy, encompassing targeted legislation on mycotoxins, consumer education and information sharing, human and institutional capacity building, training and financing, is suggested in addition to GAP, as a means of reducing human health risk associated with mycotoxin exposure in Zimbabwe.HighlightsFarm-to-fork HACCP-based mycotoxin managementHuman-centred mycotoxin management approaches are keyAgronomy, technology and legislation critical in reducing mycotoxin exposure.

The need to revisit ochratoxin A risk in light of diabetes, obesity, and chronic kidney disease prevalence

Ochratoxin A (OTA) is a mycotoxin, or fungal toxin, that contaminates multiple foodstuffs worldwide. Affected commodities include oats, wheat, maize, barley, raisins and other dried vine fruits, wine, beer, coffee, and cocoa. Although OTA has been shown to cause kidney disease, including kidney cancer, in multiple animal species, the impact of dietary OTA on human health from a global perspective has been less clear. Several epidemiological studies suggest an association between OTA exposure and human kidney disease, but evidence of causality has been limited. Nonetheless, because OTA is common in so many foodstuffs and may play a role in kidney disease, we consider it important to improve the body of evidence surrounding OTA's adverse effects to humans, as well as human dietary exposures in different parts of the world. This is especially true in the light of increasing type 2 diabetes and obesity prevalence worldwide; both conditions frequently lead to chronic kidney disease (CKD), and may synergize with dietary OTA exposure to increase CKD risk.

Evaluation of the efficacy, acceptability and palatability of calcium montmorillonite clay used to reduce aflatoxin B1 dietary exposure in a crossover study in Kenya

Acute aflatoxin exposure can cause death and disease (aflatoxicosis) in humans. Aflatoxicosis fatality rates have been documented to be as high as 40% in Kenya. The inclusion in the diet of calcium silicate 100 (ACCS100), a calcium montmorillonite clay, may reduce aflatoxin bioavailability, thus potentially decreasing the risk of aflatoxicosis. We investigated the efficacy, acceptability and palatability of ACCS100 in a population in Kenya with recurring aflatoxicosis outbreaks. Healthy adult participants were enrolled in this double-blinded, crossover clinical trial in 2014. Following informed consent, participants (n = 50) were randomised to receive either ACCS100 (3 g day^-1) or placebo (3 g day^-1) for 7 days. Treatments were switched following a 5-day washout period. Urine samples were collected daily and assessed for urinary aflatoxin M1 (AFM₁). Blood samples were collected at the beginning and end of the trial and assessed for aflatoxin B1-lysine adducts from serum albumin (AFB₁-lys). AFM₁ concentrations in urine were significantly reduced while taking ACCS100 compared with calcium carbonate placebo (β = 0.49, 95% confidence limit = 0.32-0.75). The 20-day interval included both the placebo and ACCS100 treatments as well as a washout period. There were no statistically significant differences in reported taste, aftertaste, appearance, colour or texture by treatment. There were no statistically significant differences in self-reported adverse events by treatment. Most participants would be willing to take ACCS100 (98%) and give it to their children (98%). ACCS100 was effective, acceptable and palatable. More work is needed to test ACCS100 among vulnerable populations and to determine if it remains effective at the levels of aflatoxin exposure that induce aflatoxicosis.

DNA polymerase ζ limits chromosomal damage and promotes cell survival following aflatoxin exposure

Routine dietary consumption of foods that contain aflatoxins is the second leading cause of environmental carcinogenesis worldwide. Aflatoxin-driven mutagenesis is initiated through metabolic activation of aflatoxin B₁ (AFB₁) to its epoxide form that reacts with N7 guanine in DNA. The resulting AFB₁-N7-dG adduct undergoes either spontaneous depurination or imidazole-ring opening yielding formamidopyrimidine AFB₁ (AFB₁-Fapy-dG). Because this latter adduct is known to persist in human tissues and contributes to the high frequency G-to-T mutation signature associated with many hepatocellular carcinomas, we sought to establish the identity of the polymerase(s) involved in processing this lesion. Although our previous biochemical analyses demonstrated the ability of polymerase ζ (pol ζ) to incorporate an A opposite AFB₁-Fapy-dG and extend from this mismatch, biological evidence supporting a unique role for this polymerase in cellular tolerance following aflatoxin exposure has not been established. Following challenge with AFB₁, survival of mouse cells deficient in pol ζ (Rev3L^-/-) was significantly reduced relative to Rev3L^+/- cells or Rev3L^-/- cells complemented through expression of the wild-type human REV3L. Furthermore, cell-cycle progression of Rev3L^-/- mouse embryo fibroblasts was arrested in late S/G2 following AFB₁ exposure. These Rev3L^-/- cells showed an increase in replication-dependent formation of γ-H2AX foci, micronuclei, and chromosomal aberrations (chromatid breaks and radials) relative to Rev3L^+/- cells. These data suggest that pol ζ is essential for processing AFB₁-induced DNA adducts and that, in its absence, cells do not have an efficient backup polymerase or a repair/tolerance mechanism facilitating survival.