Aflatoxin exposure in pregnant women of mixed status of human immunodeficiency virus infection and rate of gestational weight gain: a Ugandan cohort study

Level of exposure to aflatoxins during pregnancy and its association with adverse birth outcomes in Africa: a meta-analysis

BACKGROUND

Aflatoxins are various poisonous carcinogens and mutagens produced by Aspergillus species. Exposure to aflatoxins during pregnancy results in adverse birth outcomes. This meta-analysis was carried out to determine the estimates of how much aflatoxin is harmful to the pregnancy and its outcome, including birthweight, birth length, low birthweight (LBW), small for gestational age (SGA), stunting, poverty, food insecurity, income, pesticides and stillbirth, in an African context.

METHODS

Both published and unpublished studies in Africa were searched on MEDLINE, PubMed, Embase, SCOPUS, Web of Science and Google Scholar. Stata version 18.2 software was used for cleaning and analysis. The prevalence with a 95% confidence interval (CI) was estimated using the random effects model and a forest plot was used to present the findings. In addition, the heterogeneity of the study was assessed using Cochrane I2 statistics and publication bias was assessed using Egger's intercept and funnel plot.

RESULTS

This review included 28 studies with a total of 6283 pregnant women and newborns. The analysis showed the overall level of exposure to aflatoxins was 64% (95% CI 48 to 78, τ2=0.66, I2=99.34%, p=0.001). In the subgroup analysis by publication year, the highest level of exposure to aflatoxins (82% [95% CI 69 to 92]) was observed among studies published from 2020 to 2023. This study also found that exposure to aflatoxins during pregnancy had an association with prematurity, LBW, SGA and stillbirth.

CONCLUSIONS

The data analysed in this study indicated that three of every five pregnant women had exposure to aflatoxins in Africa. Moreover, pregnant women exposed to aflatoxins had a higher likelihood of having a LBW and SGA newborn. Thus governments and all stakeholders should initiate policies that mitigate the toxicity of aflatoxins in pregnant women, foetuses and newborns.

Characterization of Ugandan Endemic Aspergillus Species and Identification of Non-Aflatoxigenic Isolates for Potential Biocontrol of Aflatoxins

Acute stunting in children, liver cancer, and death often occur due to human exposure to aflatoxins in food. The severity of aflatoxin contamination depends on the type of Aspergillus fungus infecting the crops. In this study, Aspergillus species were isolated from households’ staple foods and were characterized for different aflatoxin chemotypes. The non-aflatoxigenic chemotypes were evaluated for their ability to reduce aflatoxin levels produced by aflatoxigenic A. flavus strains on maize grains. Aspergillus flavus (63%), A. tamarii (14%), and A. niger (23%) were the main species present. The A. flavus species included isolates that predominantly produced aflatoxins B1 and B2, with most isolates producing a high amount (>20 ug/µL) of aflatoxin B1 (AFB1), and a marginal proportion of them also producing G aflatoxins with a higher level of aflatoxin G1 (AFG1) than AFB1. Some non-aflatoxigenic A. tamarii demonstrated a strong ability to reduce the level of AFB1 by more than 95% when co-inoculated with aflatoxigenic A. flavus. Therefore, field evaluation of both non-aflatoxigenic A. flavus and A. tamarii would be an important step toward developing biocontrol agents for mitigating field contamination of crops with aflatoxins in Uganda.

Dietary diversity and diet quality with gestational weight gain and adverse birth outcomes, results from a prospective pregnancy cohort study in urban Tanzania

Healthy maternal diets during pregnancy are an important protective factor for pregnancy‐related outcomes, including gestational weight gain (GWG) and birth outcomes. We prospectively examined the associations of maternal dietary diversity and diet quality, using Minimum Dietary Diversity for Women (MDD‐W) and Prime Diet Quality Score (PDQS), with GWG and birth outcomes among women enrolled in a trial in Tanzania (n = 1190). MDD‐W and PDQS were derived from a baseline food frequency questionnaire. Women were monthly followed until delivery, during which weight was measured. GWG was classified based on the 2009 Institute of Medicine guidelines. Adverse birth outcomes were classified as low birth weight (LBW), small for gestational age, large for gestational age, and preterm birth. 46.2% participants had MDD‐W ≥ 5. Mean score of PDQS was 23.3. Maternal intakes of nuts, poultry, and eggs were low, whereas intakes of sugar‐sweetened beverages and refined grains were high. MDD‐W was not associated with GWG or birth outcomes. For PDQS, compared to the lowest tertile, women in the highest tertile had lower risk of inappropriate GWG (risk ratio [RR] = 0.93, 95% confidence interval [CI]: 0.87–1.00). Women in the middle tertile group of PDQS (RR = 0.72, 95% CI: 0.51–1.00) had lower risk of preterm birth. After excluding women with prior complications, higher PDQS was associated with lower risk of LBW (middle tertile: RR = 0.55, 95% CI: 0.31–0.99, highest tertile: RR = 0.52, 95% CI: 0.29–0.94; continuous per SD: RR = 0.77, 95% CI: 0.60–0.99). Our findings support continuing efforts to improve maternal diet quality for optimal GWG and infant outcomes among Tanzanian women.

•

Maternal diets are a key modifiable determinant of gestational weight gain (GWG) and birth outcomes.

•

We observed suboptimal intakes of healthy proteins and fats and high intakes of refined grains and sugar‐containing foods among well‐nourished pregnant women in urban Tanzania.

•

This study found that higher‐quality maternal diets were associated with lower risks of inappropriate GWG, low birth weight, and preterm birth.

•

This study supports the importance of high maternal diet quality and continuing efforts to promote well‐balanced maternal diets with avoiding both under‐ and over‐nutrition for optimal pregnancy outcomes among Tanzanian populations.

Aflatoxin Biosynthesis, Genetic Regulation, Toxicity, and Control Strategies: A Review

Aflatoxins (AFs) are highly toxic and cancer-causing compounds, predominantly synthesized by the Aspergillus species. AFs biosynthesis is a lengthy process that requires as minimum as 30 genes grouped inside 75 kilobytes (kB) of gene clusters, which are regulated by specific transcription factors, including aflR, aflS, and some general transcription factors. This paper summarizes the status of research on characterizing structural and regulatory genes associated with AF production and their roles in aflatoxigenic fungi, particularly Aspergillus flavus and A. parasiticus, and enhances the current understanding of AFs that adversely affect humans and animals with a great emphasis on toxicity and preventive methods.

Mycotoxins in Ethiopia: A Review on Prevalence, Economic and Health Impacts

Mycotoxigenic fungi and their toxins are a global concern, causing huge economic and health impacts in developing countries such as Ethiopia, where the mycotoxin control system is inadequate. This work aimed to review the occurrences of agriculturally essential fungi such as Aspergillus, Fusarium, and Penicillium and their major mycotoxins in Ethiopian food/feedstuffs. The incidents of crucial toxins, including aflatoxins (B1, B2, G1, G2, M1), fumonisins (B1, B2), zearalenone, deoxynivalenol, and ochratoxin A, were studied. The impacts of chronic aflatoxin exposure on liver cancer risks, synergy with chronic hepatitis B infection, and possible links with Ethiopian childhood malnutrition were thoroughly examined. In addition, health risks of other potential mycotoxin exposure are also discussed, and the impacts of unsafe level of mycotoxin contaminations on economically essential export products and livestock productions were assessed. Feasible mycotoxin mitigation strategies such as biocontrol methods and binding agents (bentonite) were recommended because they are relatively cheap for low-income farmers and widely available in Ethiopia, respectively. Moreover, Ethiopian mycotoxin regulations, storage practice, adulteration practice, mycotoxin tests, and knowledge gaps among value chain actors were highlighted. Finally, sustained public awareness was suggested, along with technical and human capacity developments in the food control sector.