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Impact assessment of organic vs. conventional farming on the thyroid
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O objetivo principal deste trabalho é avaliar e comparar qual o potencial impacto negativo da agricultura convencional e da agricultura orgânica na tiroide. As práticas de agricultura convencional utilizam agroquímicos sintéticos – muitos dos quais são disruptores endócrinos, como pesticidas – para maximizar a produtividade, enquanto as práticas de agricultura orgânica utilizam alternativas naturais para favorecer a sustentabilidade ambiental e proteger a saúde humana. Contudo, alguns estudos sugerem que os produtos de agricultura orgânica poderão apresentar contaminação residual por agroquímicos – nomeadamente pesticidas – e contribuir para a disseminação de genes de resistência a antibióticos no ambiente. A disrupção da tiroide é uma preocupação global, abrangendo algumas das patologias endócrinas mundialmente mais comuns. Estudos anteriores estabeleceram conexões entre a exposição a contaminantes de agricultura convencional com perturbações da tiroide, mas pouco se sabe sobre os efeitos da exposição a contaminantes de agricultura orgânica na tiroide. Selecionaram-se ratinhos selvagens Mus musculus como espécie bioindicadora, capturados (i) numa área agrícola convencional, (ii) numa área agrícola orgânica e (iii) em duas áreas sem práticas agrícolas (grupo de referência). Analisaram-se dados de medições histomorfométricas e histomorfológicas da tiroide, observando-se alterações na tiroide de ratinhos expostos a agricultura convencional e a agricultura orgânica, mais pronunciadas nos primeiros. Verificaram-se indícios de hipotiroidismo nos ratinhos expostos, traduzidos por uma menor espessura do epitélio e reduções relevantes na área e volume das células epiteliais comparativamente aos ratinhos não-expostos. As alterações histomorfológicas observadas nos ratinhos expostos incluíram menor esfericidade folicular, epitélio irregular, aumento de esfoliação para o coloide e aumento de inflamação do tecido tiroideu. Machos e fêmeas apresentaram as mesmas alterações da tiroide nos respetivos grupos, com pequenas diferenças em determinados parâmetros. Estes resultados sugerem que, embora a agricultura orgânica possa ser uma melhor alternativa à agricultura convencional, ela não é completamente isenta de riscos para a saúde. A exposição aos contaminantes da agricultura orgânica pode causar disrupção da tiroide, embora com efeitos menos pronunciados. No geral, os resultados obtidos suportam a necessidade de transição dos sistemas agrícolas convencionais atuais para sistemas agrícolas orgânicos.
ABSTRACT: The main objective of this work is assessing and comparing the potential negative impact of conventional farming and organic farming on the thyroid. Conventional farming practices deploy synthetic agrochemicals – many of which are endocrine-disrupting chemicals, like pesticides – to maximize crop yields, while organic farming practices rely on natural alternatives to promote environmental sustainability and protect human health. However, some studies suggest that organic farming yield may still contain residual contamination with agrochemicals – namely pesticides –, while contributing to the spread of antibiotic resistance genes in the environment. Thyroid disruption is a global concern, causing some of the most common endocrine pathologies worldwide. Previous studies have linked exposure to conventional farming contaminants with thyroid disruption, but little is known about the effects of exposure to organic farming contaminants on the thyroid. Wild mice Mus musculus were selected as bioindicator species, captured in (i) a conventional farming area, (ii) an organic farming area, and (iii) two areas without agricultural practices (reference group). Histomorphometric and histomorphological measurements of the thyroid were analyzed, revealing alterations in conventional farming- and organic farming-exposed mice. Evidence of hypothyroidism was observed in exposed mice, expressed as reduced epithelial thickness and relevant decreases in the area and volume of epithelial cells compared to non-exposed mice. Histomorphologic alterations in exposed mice included reduced follicular sphericity, irregularly-delimited epithelium, increased exfoliation into the colloid, and increased inflammation of thyroid tissue. Both male and female mice exhibited similar thyroid alterations within their groups, with only minor differences in some parameters. These results suggest that, while organic farming might be a better alternative to conventional farming, it is not completely free of health hazards. Exposure to organic farming contaminants can cause thyroid disruption, though with less pronounced effects. Overall, the results of this study support the need for a transition from current conventional farming systems towards organic farming systems.
ABSTRACT: The main objective of this work is assessing and comparing the potential negative impact of conventional farming and organic farming on the thyroid. Conventional farming practices deploy synthetic agrochemicals – many of which are endocrine-disrupting chemicals, like pesticides – to maximize crop yields, while organic farming practices rely on natural alternatives to promote environmental sustainability and protect human health. However, some studies suggest that organic farming yield may still contain residual contamination with agrochemicals – namely pesticides –, while contributing to the spread of antibiotic resistance genes in the environment. Thyroid disruption is a global concern, causing some of the most common endocrine pathologies worldwide. Previous studies have linked exposure to conventional farming contaminants with thyroid disruption, but little is known about the effects of exposure to organic farming contaminants on the thyroid. Wild mice Mus musculus were selected as bioindicator species, captured in (i) a conventional farming area, (ii) an organic farming area, and (iii) two areas without agricultural practices (reference group). Histomorphometric and histomorphological measurements of the thyroid were analyzed, revealing alterations in conventional farming- and organic farming-exposed mice. Evidence of hypothyroidism was observed in exposed mice, expressed as reduced epithelial thickness and relevant decreases in the area and volume of epithelial cells compared to non-exposed mice. Histomorphologic alterations in exposed mice included reduced follicular sphericity, irregularly-delimited epithelium, increased exfoliation into the colloid, and increased inflammation of thyroid tissue. Both male and female mice exhibited similar thyroid alterations within their groups, with only minor differences in some parameters. These results suggest that, while organic farming might be a better alternative to conventional farming, it is not completely free of health hazards. Exposure to organic farming contaminants can cause thyroid disruption, though with less pronounced effects. Overall, the results of this study support the need for a transition from current conventional farming systems towards organic farming systems.
Descrição
Dissertação de Mestrado, Ciências Biomédicas, 30 de janeiro de 2026, Universidade dos Açores.
Palavras-chave
Organic agriculture Organic fertilizers Conventional agriculture Agrochemicals Pesticides Chronic exposure Mus musculus Endocrine disruption Hypothyroidism
Contexto Educativo
Citação
COELHO, Nádia Maria Pereira. (2025). Impact assessment of organic vs.
conventional farming on the thyroid. Ponta Delgada: Universidade dos Açores, 2025, 71 p. Dissertação de Mestrado em Ciências Biomédicas. Disponível em http://hdl.handle.net/10400.3/9009