Exposure to environmental pesticides alters gut microbes, increasing the urgency of biological transition
(Beyond pesticides, May 12, 2022) A report published in Environmental health finds that exposure to environmentally relevant concentrations of pesticides can alter gut microbial communities, as demonstrated by fecal samples. Finished 300 environmental contaminants and their by-products, including pesticides, are chemicals commonly found in human blood and urine samples. Abundant evidence demonstrates that environmental contaminants, including pesticides, negatively affect human mouth and gut microbes. However, faecal samples provide an accurate representation of the microbial community existing in the gut. These toxic substances can alter hormonal metabolism, which has adverse effects on health. Adverse health effects environmental contaminants include reproductive and developmental defects, diabetes, cardiovascular disease, liver disease, obesity, thyroid disorders and improper immune functioning. Although studies show how chemical exposures affect human health, more and more research is now asking how these toxic chemicals influence gut health. Therefore, studies like these highlight the importance of assessing how chemical contaminants disrupt normal bodily function through changes in the microbiome. The report notes, “Our findings underscore the need for future dietary intervention studies to understand the effects of pesticide exposure on the gut microbiome and possible health consequences.”
Researchers looked at dietary exposure to 186 common pesticide residues in faeces to determine microbiome impacts in 65 twins in the UK. The composition of the gut microbiota is associated with dietary habits, different life stages, geographic location, exercise, antibiotics, and disease states. However, the researchers investigated whether these associations could also impact pesticide residue levels in feces to indicate alterations in gut health. Using metagenomics and metabolomics, researchers measured the metabolic activity of microbes in feces and pesticides in urinary excretion to note any bodily changes.
The report reveals that all urine samples contain residues of pyrethroid or organophosphate insecticides, with 53% of urine samples containing glyphosate. People who eat more fruits and vegetables grown with chemical-intensive practices have higher concentrations of organophosphate residues. Although the excretion of urinary metabolites (degradation products of pesticides) does not correlate with gut microbial changes, there are 34 associations between pesticide residue concentration and metabolite residues in feces and health. intestinal. Excretion of glyphosate in the faeces is correlated with increased bacterial species richness, fatty acid metabolites, and phosphate concentrations in the gut. For pyrethroids, the metabolite of deltamethrin, Br2CA, has a positive association with the phytoestrogens enterodiol (dietary estrogen) and negative associations with specific amino acids in the gut.
The gut microbiome is a group of microorganisms, including bacteria, archaea, viruses, and fungi, that plays crucial roles in digestion, bodily function, detoxification, and regulation of the immune system and central nervous system . Throughout the gut biome, exposure to pesticides can increase or exacerbate the adverse effects of additional environmental toxicants on the body. Since the gut microbiome shapes metabolism, it can mitigate some toxic effects of environmental chemicals. However, with prolonged exposure to various environmental contaminants, critical chemical-induced changes can occur in gut microbes, influencing adverse health effects. Like gut microbes, soil microbes are essential to the functionality of the soil ecosystem. Toxic chemicals damage soil microbiota by decreasing and altering microbial biomass and soil microbiome composition (diversity). Pesticide use contaminates the soil and creates a bacteria-dominated ecosystem, causing “vacant ecological niches, so that organisms that were rare become abundant and vice versa.” Bacteria outcompete beneficial fungi, improving soil productivity and increasing carbon sequestration capacity. The resulting soil ecosystem is unhealthy and imbalanced, with a reduction in natural nutrient cycling and resilience. Thus, plants grown under such conditions are more vulnerable to pests and pathogens. Additionally, the effects of climate change are only exacerbating the threats to soil health, as studies show a link between global climate change and a high loss of microbial organisms in the soil ecosystem.
The findings add to the growing body of environmental studies linking pesticide exposure to metabolic distress and respective health consequences. Although previous studies suggest that exposure to pesticides in the environment disrupts the gut microbiome, this report is the first to find an association between pesticide excretion and exposure to environmentally relevant pesticide concentrations. . Although most pesticide exposures decrease microbial species richness, some chemicals, such as glyphosate, increase bacterial species richness. However, an increase in species richness is not always positive because it cannot measure the function of how these bacteria work together. Studies show that functional diversity declines faster with agricultural intensification than species richness. Functional diversity involves the interaction of species based on similarity in behavioral, morphological, physiological or resource use, as it is most closely related to ecosystem function. Additionally, an increase in species richness in the gut microbiome may allow more resistant bacteria to thrive and outcompete other beneficial bacteria, regardless of their pathogenic potential. For example, glyphosate kills human-beneficial bacterial species incorporated into probiotics while allowing harmful bacteria to persist, leading to resistance. Similarly, soils exposed to glyphosate contain a greater abundance of genes associated with antibiotic resistance and a greater number of transferable genetic material between species. Antibiotic resistance can trigger longer-lasting infections, higher medical expenses, the need for more expensive or dangerous drugs, and the inability to treat life-threatening illnesses. Nevertheless, studies show that an organic diet reduces individual exposure to pesticides, demonstrating a significant reduction in body concentration of pesticides. Therefore, organic can also protect the health of human gut microbes by reducing the number of toxic chemicals in the body.
The report concludes: “We found that people who regularly consume organic produce had higher Healthy Eating Index values, but other lifestyle choices are in all likelihood contributing factors as well. . We provide the first evidence of an association between pesticide excretion and changes in gut microbiome metabolism at environmental exposure levels in the UK population. Our results highlight the need for future dietary intervention studies to understand the impact of pesticide exposure on gut microbiome composition and function and its implications for health.
To improve and maintain microbial communities, and therefore human, animal and environmental health, the use of toxic pesticides must cease. Beyond Pesticides challenges the registration of toxic chemicals because of their impacts on soil, air, water and our health. As legal battles continue, the agricultural system should phase out the use of toxic synthetic herbicides to avoid the myriad problems they cause. Instead, Beyond Pesticides argues that safer alternatives are available and that organic practices can protect public health and the environment. In addition to the positive effects on the human microbiome, organically grown foods (i.e. milk, meat, strawberriestomatoes and a range of other foods) contain a much more diverse bacterial community than their conventional counterparts.
Additionally, buying organic foods when possible can help reduce exposure and the resulting adverse health effects. Emphasis should be placed on converting to regenerative organic systems and using the least toxic pest control to mitigate harmful exposure to pesticides. Learn more about the soil and gut microbiota and its importance via Beyond Pesticide’s Pesticides and You review. Plus, learn more about how pesticides affect human health by visiting Beyond Pesticides’ Pesticide Induced Diseases Database, which supports the clear need for strategic action to move from addiction to pesticides.
All unattributed positions and opinions in this article are those of Beyond Pesticides.
Sources: Environmental health