26
Jan
Common Fungicide Adds to Growing List of Pesticides Linked to Gastrointestinal and Microbiome Damage
(Beyond Pesticides, January 26, 2023) A study published in Food Safety and Toxicology finds that the widely used fungicide azoxystrobin (AZO), used in food production and turf management, can disrupt the function of the intestinal (colonic) barrier responsible for the absorption of nutrients and defense against harmful substances. This and other similar data are important because the U.S. Environmental Protection Agency (EPA), with its required pesticide testing protocol, says that the chemical has “low acute and chronic toxicity to humans, birds, mammals, and bees,” and speaks to the need for the agency to modernize its registration requirements. [The agency does note that AZO is “is highly toxic to freshwater fish, freshwater invertebrates, and estuarine/marine fish, and very highly toxic to estuarine/marine invertebrates.]
AZO is a broad-spectrum chemical used in wheat, barley, oats, rye, soya, cotton, rice, strawberry, peas, beans, onions, and a long list of other vegetables, as well as on lawns and golf courses, on a range of fungal diseases. The intestinal (colonic) barrier prevents the internal environment from damage caused by exogenous toxins to ensure internal homeostasis, impeding incidences of systemic inflammatory response syndrome (SIRS), sepsis, and multiple organ dysfunction syndrome (MODS).
The intestines host a group of microorganisms that form the gut microbiome. These microorganisms, including bacteria, archaea, viruses, and fungi, play a crucial role in digestion, bodily function, detoxification, and immune and central nervous system regulation. Ample evidence demonstrates environmental contaminants like pesticides negatively affect gut microbes. Through the gut biome, pesticide exposure can enhance or exacerbate the adverse effects of additional environmental toxicants on the body. Studies even find low levels of pesticide exposure during pregnancy or childhood cause adverse health effects, including metabolic disorders tied to gut microbiome disruption (dysbiosis).
Although studies show how chemical exposures affect overall human health, a growing body of peer-reviewed scientific literature is now questioning how these toxic chemicals influence gut health and the subsequent occurrence of diseases. The study notes, “The results of this study will strongly support new insights that the gut microbiota can be a key target of the health effects of pesticide exposure.”
Researchers divided 36 male mice into three treatment groups of 12: the control group with deionized water, low dose of azoxystrobin (L-AZO) in deionized water, a high dose of azoxystrobin (H-AZO) in deionized water. After a week of treatment, the researchers collected microbial contents from the colons of each group for transplantation into donor mice. Researchers orally administered the collected microbiota to donor mice to determine the correlations between the presence of these biota, metabolites of gut contents, and traits associated with colonic barrier function. The results reveal AZO exposure altered the metabolic profile of microbes in the gut, inducing gut dysbiosis, leading to structural damage of the colon and colonic inflammatory response. Although the L-AZO treatment group experiences no changes in body weight compared to the control group, the H-AZO treatment group has significantly reduced body weight and weight gain.
A gut microbiome is a group of microorganisms, including bacteria, archaea, viruses, and fungi, that plays a crucial role in digestion, bodily function, detoxification, and immune and central nervous system regulation. The gut, also known as the “second brain,” shares similar structural and chemical parallels to the brain. The microbiota in the gut plays a crucial role in lifelong digestion, immune and central nervous system regulation, as well as other bodily functions.
Through the gut biome, pesticide exposure can enhance or exacerbate the adverse effects of additional environmental toxicants on the body. Since the gut microbiome shapes metabolism, it can mediate some toxic effects of environmental chemicals. However, with prolonged exposure to various environmental contaminants, critical chemical-induced changes may occur in the gut microbes, influencing adverse health outcomes.
The impacts of pesticides on the human gut microbiome represent another pesticide assault on human health. Because the biome harbors between 10 and 100 trillion symbiotic microbes, pesticide exposure has effects on some of those bacteria. The human gastrointestinal tract and its digestive processes (a.k.a., the “gut”) mediate the function of several systems. Dysfunction of the gut microbiome is associated with a host of diseases, including cardiovascular disease, some cancers, multiple sclerosis, diabetes, asthma, Crohn’s disease, Parkinson’s disease, and inflammatory bowel disease, as well as allergies, autism, depression, obesity, and other disorders or syndromes.
This study is the first to demonstrate AZO’s effect on colonic barrier function in mammals which is the first barrier of the host against exogenous (external) pollutants. AZO’s effect on the gut results in changes in the tight junctions of intestinal epithelial cells and the integrity of the intestinal barrier for protection. Additionally, AZO exposure alters the ability of gut bacteria to break down proteins, fats, carbohydrates, or other macronutrients into residual metabolites, which constitute the metabolic profile. For instance, gut bacteria break down fatty acid chains into dietary fibers, a process essential in modulating the immune system, gene expression, and cell multiplying, among others.
AZO is far from the only pesticide linked with the growing global metabolic disorder incidence rates over the past few decades. The World Health Organization (WHO), European Union (EU), and endocrine disruptor expert (deceased) Theo Colborn, Ph.D., classify over 55 to 177 chemical compounds (e.g., detergents, disinfectants, plastics, and pesticides, etc.) as endocrine disruptors associated with notorious metabolic disorders like diabetes/obesity that can span generations. However, endocrine disruption is the mechanism for several adverse health endpoints, interacting with the body’s hormone system and affecting the development, growth, reproduction, and behavior of both animals and humans.
To improve and sustain gut microbiome health, the use of toxic pesticides must end. Beyond Pesticides challenges the registration of toxic chemicals due to their impacts on soil, air, water, and health. Instead, emphasis on converting to regenerative-organic systems and using least-toxic pest control to mitigate harmful exposure to pesticides, restore soil health, and reduce carbon emissions, should be the main focus. Public policy must advance this shift rather than allow unnecessary reliance on pesticides. Moreover, purchasing organic food when possible can help curb exposure and adverse health effects. Beyond Pesticides holds that safer alternatives are available, and organic practices can protect public health and the environment. In addition to positive impacts on the human microbiome, organically grown food (e.g., milk, meat, strawberries, tomatoes, and a range of other foods) contain a much more diverse bacterial community than their chemical-intensively grown counterparts.
Learn more about soil and gut microbiota and their importance via Beyond Pesticide’s Pesticide and You Journal article, “Sustaining Life From Soil Microbiota to Gut Microbiome.” Additionally, 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 shift from pesticide dependency.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Food Safety and Toxicology
