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Aflatoxins, Metabolic Disorders, and Infancy in the Global South

Abstract

Aflatoxin exposure remains a critical public health issue in many low- and middle-income countries in the Global South, particularly for infants. Produced by Aspergillus species, aflatoxins contaminate food staples under warm, humid, and poorly controlled storage conditions. Early-life (in utero and infant) exposure has been linked to metabolic disruption, epigenetic reprogramming, impaired growth, and immune dysfunction. This paper synthesizes mechanistic, epidemiological, and policy evidence; it then offers actionable policy recommendations for national governments, international agencies, and community stakeholders to mitigate aflatoxin-driven metabolic risks in infancy.

1. Introduction

Aflatoxins, especially aflatoxin B1 (AFB1), are among the most potent naturally occurring mycotoxins. Their prevalence in key food staples (e.g., maize, groundnuts) is especially high in warm, humid climates common in Sub-Saharan Africa, South Asia, and parts of Latin America. Infants in these regions are especially vulnerable due to (1) early weaning with contaminated complementary foods, (2) high reliance on breast milk that may contain aflatoxin metabolites, (3) immature detoxification mechanisms, and (4) the critical developmental window (organogenesis, epigenetic programming).

Emerging evidence suggests that aflatoxin exposure in early life is not just a carcinogenic risk but may program metabolic disease, impair growth, and weaken immune function. However, policy responses remain fragmented, and many interventions fail to prioritize infancy or do not tackle metabolic outcomes. This paper critically reviews available evidence and proposes policy strategies adapted to low-resource settings.

2. Exposure Pathways in Infancy

2.1 Maternal Transmission & Breast Milk

  • AFB1 ingested by mothers can be biotransformed into Aflatoxin M1 (AFM1), which is excreted in breast milk, exposing exclusively breastfed infants.

  • Systematic reviews indicate widespread detection of AFM1 in breast milk in African settings. aflatoxinpartnership.org

2.2 Complementary Foods & Household Storage

  • In resource-limited settings, improperly dried maize, groundnuts, or other cereals often become contaminated during household storage.

  • Informal markets and traditional weaning foods may not be regulated, leading to high aflatoxin contamination risks.

2.3 In Utero Exposure

  • Pregnant women exposed to AFB1 can transfer the toxin (or its metabolites) to the fetus, potentially altering fetal development.

  • A study in The Gambia found that maternal AFB1 exposure (measured as AFB-albumin adducts) was associated with differential DNA methylation in infants’ white blood cells, including growth- and immune-related genes (e.g., IGF1, TLR2). OUP Academic+1

2.4 Dietary Intake Later in Infancy

  • Infants begin to consume cereal-based porridges, nut-based complementary foods, and other staples that may carry high aflatoxin levels.

  • A recent study in Rwanda among children aged 6–59 months showed that urinary AFM1 (a biomarker of AFB1 exposure) was associated with malnutrition (e.g., stunting, underweight). ILRI

2.5 Milk Consumption

  • Pasteurized milk can also contain AFM1. For example, a study in Addis Ababa found that over half the pasteurized milk sampled had detectable AFM1, posing elevated risk especially in young children. ejfood.org

3. Mechanisms of Toxicity & Metabolic Disruption in Infancy

3.1 Growth Factor Disruption: IGF-1 Axis

  • Aflatoxin-albumin adducts (AF-alb) have been shown to inversely correlate with IGF-1 and IGF-binding protein 3 (IGFBP-3) in African children, affecting height and weight. PubMed+2PMC+2

  • In vitro, exposure of human hepatocytes to AFB1 reduces expression of IGF1 and IGFBP3 genes, suggesting a mechanistic link to growth impairment. PMC+1

  • This suppression of the IGF axis may contribute to stunting by impairing the liver’s capacity to produce IGF-1, thereby limiting growth potential.

3.2 Epigenetic Programming

  • Prenatal exposure to AFB1 is associated with epigenetic modifications (DNA methylation) in infants. In The Gambia, maternal exposure correlated with altered methylation at CpG sites in genes including IGF1, FGF12, and immune-regulatory genes. OUP Academic+1

  • These epigenetic changes could influence long-term regulation of growth, metabolism, and immunity.

3.3 Metabolic and Hormonal Alterations

  • Animal studies (e.g., rat models) show that perinatal AFB1 exposure leads to persistent changes in lipid metabolism, hormone levels (reproductive, thyroid), and DNA methylation of growth-related genes. MDPI

  • Such early-life perturbations could predispose individuals to insulin resistance, non-alcoholic fatty liver disease (NAFLD), and other metabolic disorders later in life.

3.4 Immune & Gut Impacts

  • Aflatoxin exposure can impair immune function by altering methylation in immune-related genes (e.g., TLR2) as seen in infant epigenetic studies. OUP Academic

  • Chronic exposure may affect gut integrity, leading to systemic inflammation and impaired nutrient absorption—mechanisms that also intersect with metabolism.

4. Epidemiological Evidence on Health Outcomes

4.1 Growth Impairment & Stunting

  • A comprehensive meta-analysis (2023) found that AFB1 exposure is significantly associated with lower height-for-age (HAZ) and weight-for-age (WAZ) z-scores, and increased odds of stunting and underweight in children. PubMed

  • However, not all studies agree: for example, a birth cohort from Dhaka, Bangladesh reported no significant association, suggesting possible exposure-threshold effects or context-dependent risk. PubMed

4.2 Birth Outcomes

  • In a Tanzanian cohort of pregnant women, almost all had detectable AFB1-lysine adducts, but the study reported no significant association with birth weight or small-for-gestational age after adjustment. PubMed

  • The finding points to complex interactions (e.g., nutritional status, co-exposures) and perhaps non-linear dose-response relationships.

5. Public Health & Policy Implications

5.1 Burden & Inequity

  • Infants in low-resource settings bear a disproportionate burden of aflatoxin exposure with potential lifelong metabolic consequences.

  • The convergence of poverty, weak regulation, poor storage practices, and climate vulnerability exacerbates risk.

5.2 Long-Term Health Costs

  • Early-life exposure may contribute to the developmental origins of metabolic disease (e.g., insulin resistance, metabolic syndrome), with implications for healthcare systems already constrained in many LMICs.

5.3 Regulatory Gaps

  • Many countries lack strong enforcement of aflatoxin limits in complementary foods, cereal staples, and milk.

  • Monitoring systems for aflatoxin exposure in mothers and infants are weak or absent.

6. Policy Recommendations

  1. Surveillance & Biomonitoring

    • Implement routine testing of AFB1 in staple foods, weaning flours, and breast milk.

    • Track biomarkers (e.g., AF-albumin, AFM1) in maternal and infant cohorts.

  2. Regulation & Standards

    • Enforce strict maximum permissible levels of AFB1 in infant foods.

    • Regulate AFM1 in milk, especially in regions with high dairy consumption.

  3. Storage & Agricultural Interventions

    • Promote use of hermetic storage (e.g., PICS bags), solar drying, and moisture meters among smallholder farmers.

    • Support development and adoption of aflatoxin-resistant crop varieties.

  4. Early-Life Interventions

    • Integrate aflatoxin risk reduction into maternal and child nutrition programs.

    • Educate caregivers on sorting, discarding moldy grains, and safe food preparation.

  5. Research & Innovation

    • Fund longitudinal cohorts to study metabolic outcomes in infants exposed to aflatoxin.

    • Invest in detection technologies (point-of-care aflatoxin tests, rapid assay kits).

    • Explore epigenetic and multi-omics profiling to understand programming effects.

  6. Policy Collaboration & Regional Harmonization

    • Encourage regional regulatory alignment (e.g., African Union, ASEAN) on toxin limits and food safety.

    • Mobilize international funding to support climate-resilient and aflatoxin-safe food systems.

7. Conclusion

Aflatoxin exposure in infancy is not only a carcinogenic risk but potentially a driver of metabolic and developmental disorders. The evidence—from growth-factor disruption, epigenetic programming, to epidemiological associations—supports a strong case for prioritizing infants in aflatoxin mitigation policies. Addressing this challenge requires an integrated approach: regulatory reform, agricultural innovation, surveillance, and community-level interventions. Protecting infants from aflatoxin is both a public health imperative and a moral duty.

References

  1. Castelino, J. M., Routledge, M. N., Wilson, S., Dunne, D. W., Mwatha, J. K., Gachuhi, K., … Gong, Y.-Y. (2014). Aflatoxin exposure is inversely associated with IGF1 and IGFBP3 levels in vitro and in Kenyan children. Molecular Nutrition & Food Research, 59(3), 574–581. PMC+1

  2. Hernández-Vargas, H., Castelino, J., Silver, M. J., Domínguez-Salas, P., Cros, M.-P., Durand, G., … Gong, Y.-Y., & Routledge, M. N. (2015). Exposure to aflatoxin B1 in utero is associated with DNA methylation in white blood cells of Gambian infants. International Journal of Epidemiology, 44(4), 1238–1248. OUP Academic+1

  3. Shirima, C. P., Kimanya, M. E., Routledge, M. N., Srey, C., Wild, C. P., & Gong, Y.-Y. (2015). Evidence of early childhood exposure to aflatoxin in Tanzania. In IARC Monographs volume 105: Some naturally occurring substances. International Agency for Research on Cancer. IARC Publications

  4. Matabishi, M. A., Mutua, F., Lindahl, J. F., Hahirwa, I., Umugwaneza, M., Musafili, A., & Munyanshongore, C. (2025). Aflatoxin B1 exposure and its association with nutritional status of children receiving cereal-based supplementary foods at health centers in Rwanda. African Journal of Food, Agriculture, Nutrition and Development. ILRI

  5. Tadesse, H., Tamene, A., & Dessie, G. (2024). Aflatoxin M1 exposure and health risk assessment in children and adults due to pasteurized milk consumption in Addis Ababa, Ethiopia. European Journal of Agriculture and Food Sciences, 6(2). ejfood.org

  6. Ismail, A., et al. (2023). A systematic review with meta-analysis of the relation of aflatoxin B1 to growth impairment in infants/children. (Meta-analysis). PubMed

  7. Shirima, C. P., Kimanya, M. E., & Gong, Y.-Y. (2019). Aflatoxin exposure in utero and birth and growth outcomes in Tanzania. Maternal & Child Nutrition. PubMed

  8. Yuan, L., & Wang, J. (2021). Early-life Aflatoxin B1 exposure in rats: alterations in lipids, hormones, and DNA methylation. International Journal of Environmental Research and Public Health, 18(2), 589. MDPI

  9. The Aflatoxin Partnership. (2021). The aflatoxin situation in Africa: Systematic literature review. Report. aflatoxinpartnership.org

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