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

Maternal dietary exposure to mycotoxin aflatoxin B1 promotes intestinal immune alterations and microbiota modifications increasing infection susceptibility in mouse offspring

Mycotoxins are secondary metabolites produced by fungi occurring in food that are toxic to animals and humans. Early-life mycotoxins exposure has been linked to diverse pathologies. However, how maternal exposure to mycotoxins impacts on the intestinal barrier function of progeny has not been explored. Here, exposure of pregnant and lactating C57Bl/6J female mice to aflatoxin B₁ (AFB₁; 400 μg/kg body weight/day; 3 times a week) in gelatine pellets, from embryonic day (E)11.5 until weaning (postnatal day 21), led to gut immunological changes in progeny. The results showed an overall increase of lymphocyte number in intestine, a reduction of expression of epithelial genes related to microbial defence, as well as a decrease in cytokine production by intestinal type 2 innate lymphoid cells (ILC2). While susceptibility to chemically induced colitis was not worsened, immune alterations were associated with changes in gut microbiota and with a higher vulnerability to infection by the protozoan Eimeria vermiformis at early-life. Together these results show that maternal dietary exposure to AFB₁ can dampen intestinal barrier homeostasis in offspring decreasing their capability to tackle intestinal pathogens. These data provide insights to understand AFB₁ potential harmfulness in early-life health in the context of intestinal infections.

Dietary aflatoxin exposure of lactating mothers of children 0-6 months in Makueni County, Kenya

The southeastern region of Kenya is prone to aflatoxin outbreaks, yet maternal and infant aflatoxin intake levels remain unclear. We determined dietary aflatoxin exposure of 170 lactating mothers breastfeeding children aged 6 months and below in a descriptive cross-sectional study involving aflatoxin analysis of maize-based cooked food samples (n = 48). Their socioeconomic characteristics, food consumption patterns and postharvest handling of maize were determined. Aflatoxins were determined using high-performance liquid chromatography and enzyme-linked immunosorbent assay. Statistical analysis was conducted using Statistical Package Software for Social Sciences (SPSS version 27) and Palisade's @Risk software. About 46% of the mothers were from low-income households, and 48.2% had not attained the basic level of education. A generally low dietary diversity was reported among 54.1% of lactating mothers. Food consumption pattern was skewed towards starchy staples. Approximately 50% never treated their maize, and at least 20% stored their maize in containers that promote aflatoxin contamination. Aflatoxin was detected in 85.4% of food samples. The mean of total aflatoxin was 97.8 μg/kg (standard deviation [SD], 57.7), while aflatoxin B1 was 9.0 μg/kg (SD, 7.7). The mean dietary intake of total aflatoxin and aflatoxin B1 was 7.6 μg/kg/b.w.t/day (SD, 7.5) and 0.6 (SD, 0.6), respectively. Dietary aflatoxin exposure of lactating mothers was high (margin of exposure < 10,000). Sociodemographic characteristics, food consumption patterns and postharvest handling of maize variably influenced dietary aflatoxin exposure of the mothers. The high prevalence and presence of aflatoxin in foods of lactating mothers are a public health concern and calls for the need to devise easy-to-use household food safety and monitoring measures in the study area.

Mycotoxin communications: Managing messages for different audiences

Mycotoxins, such as aflatoxins, fumonisins, trichothecenes, and zearalenone, are increasing in visibility as a public health threat through both acute and chronic exposure in food. USAID through its Feed the Future program has sponsored research in Nepal on mycotoxin contamination and the correlated high levels of stunting in children under age five. Communicating about mycotoxins is a complicated matter, as is communicating about any potentially serious economic or health threat that may be difficult to control. Two nominal group workshops in Nepal focused on identifying problems from multiple perspectives and developing potential communication strategies to mitigate the problem and potential concerns about it. Target audiences were identified along with their interests and effective channels to communicate with and within them. The first audience to work with is the government, as it must understand and value the problem and help generate confidence in potential regulatory and mitigation processes. Producers, educators and health professionals are the next audiences to address as they are the most closely involved with the problem. Consumer engagement is last, with a communication goal of sharing information to heighten awareness and minimize unwarranted public concern.

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.

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.

Effects of Prenatal Exposure to Aflatoxin B1: A Review

Aflatoxins are mycotoxins produced as secondary fungal metabolites. Among them, aflatoxin B1 (AFB1) stands out due to its genotoxic and mutagenic potential, being a potent initiator of carcinogenesis. In this review, the outcomes from the published literature in the past 10 years on the effects of AFB1 pathophysiological mechanisms on embryological and fetal development are discussed. In several animal species, including humans, AFB1 has a teratogenic effect_, resulting in bone malformations, visceral anomalies, lesions in several organs, and behavioral and reproductive changes, in addition to low birth weight. The mutagenic capacity of AFB1 in prenatal life is greater than in adults, indicating that when exposure occurs in the womb, the risk of the development of neoplasms is higher. Studies conducted in humans indicate that the exposure to this mycotoxin during pregnancy is associated with low birth weight, decreased head circumference, and DNA hypermethylation. However, as the actual impacts on humans are still unclear, the importance of this issue cannot be overemphasized and studies on the matter are essential.

Aflatoxin exposure and child nutrition: measuring anthropometric and long-bone growth over time in Nepal

BACKGROUND

Naturally occurring aflatoxins may contribute to poor growth and nutritional statuses in children.

OBJECTIVES

We analyzed the relationship between contemporary and lagged aflatoxin exposure and 1) length-for-age z-score (LAZ); and 2) length, knee-heel length, stunting, weight-for-age z-score (WAZ), and weight-for-length z-score (WLZ).

METHODS

We conducted a longitudinal birth cohort study involving 1675 mother-infant dyads in rural Nepal. Participants were repeatedly visited from pregnancy to 2 years of age (2015-2019). One blood sample was collected during pregnancy and 4 samples were collected from the children at 3, 6, 12, and 18-22 months of age to measure concentrations of aflatoxin B1 (AFB1)-lysine adduct. Multivariate linear fixed-effects and logistic models with generalized estimating equations were used to identify associations between child growth and aflatoxin exposure.

RESULTS

AFB1-lysine adducts were detected in the majority of children (at 3 months, 80.5%; at 6 months, 75.3%; at 12 months, 81.1%; and at 18-22 months, 85.1%) and in 94.3% of pregnant women. Changes in contemporary ln child AFB1-lysine adduct concentrations were significantly associated with changes in LAZ (β, -0.05; 95% CI, -0.09 to -0.02; P = 0.003), length (β, -0.19; 95% CI, -0.29 to -0.10; P < 0.001), knee-heel length (β, -0.09; 95% CI, -0.13 to -0.05; P < 0.001), and WAZ (β, -0.04; 95% CI, -0.07 to -0.005; P = 0.022). Serum aflatoxin concentrations were associated with stunting (OR, 1.18; 95% CI, 1.05-1.32; P = 0.005). Similar results were found in the models using changes in contemporary ln AFB1 adjusted for changes in child weight, with significant associations with changes in WLZ (β, -0.07; 95% CI, -0.10 to -0.03; P < 0.001). Changes in time-lagged ln AFB1 (unadjusted and adjusted for changes in child weight) were associated with changes in length and knee-heel length.

CONCLUSIONS

Our results add to the growing body of evidence confirming chronic aflatoxin exposure and suggest that exposure is significantly correlated with various negative growth outcomes, which may vary by child weight status. This trial was registered at clinicaltrials.gov as NCT03312049.

Evaluation of acute and chronic exposure to aflatoxin B1 in indigenous women of the Huasteca Potosina, Mexico

Aflatoxin B₁ (AFB₁) is one of the most studied mycotoxins due to its high occurrence in food and its hepatotoxic, immunosuppressive, carcinogenic, childhood growth, genotoxic, mutagenic, and teratogenic effects in humans and animals. Exposure to AFB₁ is reported to be both, acute and chronic; the main exposure pathway to AFB₁ is through the intake of contaminated food. In Mexico, although the reports of several studies addressing the problem of aflatoxins in maize and other foods, the evidence has been centered on exposure to AFB₁ and to the quantification of the Aflatoxins themselves, but there is null evidence about genotoxic effects of aflatoxins in vulnerable populations. Therefore, this study focused on assessing chronic AFB₁ exposure through the AFB₁-lys biomarker adduct and acute exposure through total AFB₁-DNA adducts in women from a rural indigenous community in the Huasteca Potosina (Mexico). A hundred percent of the studied population presented total AFB₁-DNA and AFB₁-lys adducts in concentrations of 1.08 (0.48-1.34) μmol of adduct/mol of DNA and 2.33 (1.08-102.6) pg/mg of albumin respectively (median (min-max)). Thus, continuous monitoring and important changes in regulations are desired and recommended. The results in this study provide enough evidence to support the toxic effects that the exposure to AFB₁ represents, as well as the population risk that it poses, and in the same sense, the current need to create an intervention program that directly influences the control of the sources of exposure in order to reduce it.