Microbial Toxins

The Summary

Links Between Microbial Toxins and Diabetes/Obesity

Only a handful of studies published in scientific journals have examined the potential role of microbial toxins in diabetes development.

According to a review, "a final conclusion concerning the causal role of microbes in the pathogenesis [development] of type 1 diabetes has not been made." (Lammi et al. 2005).

The Details

About Microbial Toxins

Microbial toxins are produced by microorganisms (bacteria, fungi, viruses, etc.) that can be toxic and contaminate food crops, especially root vegetables (if found in soil). For example, the bacterium Streptomyces can produce bafilomycin, a toxic antibiotic and immune suppressant (Myers et al. 2003). Exposure to these toxins may damage beta cells, aggravate beta cell death and progression to diabetes (Hettiarachchi et al. 2008a). Mycotoxins are produced by fungi in particular and also contaminate food.

Also see the Factsheet on Mold from the National Institute of Environmental Health Sciences (NIEHS).

Human Studies

A study from Sweden found that prenatal exposure to various chemicals, including the mycotoxin deoxynivalenol (as well as PFAS and BPS), may contribute to the development of autoimmune diseases, including type 1 diabetes (Karthikeyan et al.  2024).

Eating root crops such as potatoes during pregnancy might be expected to increase the risk of type 1 diabetes in offspring later in life. However, potato consumption during pregnancy has been associated with a delayed later risk of type 1-related autoimmunity in children (Lamb et al. 2008).

A preliminary study from Poland found that mold and bacteria levels in the air were associated with an increased incidence of type 1 diabetes, so this research will be something to watch (Michalska et al. 2017).

Laboratory Studies

When low levels of balfilomycin is injected into mice, it impairs glucose tolerance, reduces islet size, and decreased beta cell mass (Myers et al. 2003). Repeated low level doses of balfilomycin led to lower islet size in female mice. Another microbial toxin, concanamycin, worsened glucose tolerance in female mice (Hettiarachchi et al. 2006a). 

Long-term exposure to ochratoxin A, a widespread toxin found on food or in water-damaged houses, causes higher blood glucose levels, lower insulin levels, and pancreatic damage in rats (Mor et al. 2017).

Exposure to the mycotoxins (toxins produced by fungi) deoxynivalenol and zearalenone (both of which affect cereal crops) affects the glucose metabolism in the liver of mice (Ji et al. 2017). In rats, deoxynivalenol causes immune system response and inflammation and intestinal problems as well (Payros et al. 2020). 

Microcystin-LR, produced by freshwater bacteria and algal blooms (and which can be in drinking water), also is toxic to beta cells (Zhao et al. 2017; Zhao et al. 2016). It also affects glucose and metabolism in zebrafish, an animal used to study the effects of toxic chemicals (Chen et al. 2017; Wang et al. 2020). In China, there are high levels of microcystin-LR in a certain lake, and the people living near this lake have high rates of type 2 diabetes. When mice drank the lake water, they developed insulin resistance (Zhang et al. 2018).

Mycotoxins can also adversely affect gut microbiota, gut inflammation, and gut permeability (Liew and Mohd-Redzwan, 2018), which in turn are linked to type 1 diabetes development (see the Diet and the Gut page).

Exposure During Development

When parent non-obese diabetic (NOD) mice (used in the lab as a model for type 1 diabetes), were fed balfilomycin from conception through pregnancy, their offspring had accelerated diabetes development as well as a higher frequency of diabetes. The development of the islets in the pancreas was disrupted in the exposed mice (Hettiarachchi et al. 2004).

In other mice, in utero exposure to balfilomycin disrupts the development of beta cells and encourages beta cell death (Hettiarachchi et al. 2008b).

Studies on Cells

Beta cells treated with balfilomycin alters insulin signalling in beta cells. Low levels increase insulin signalling, and higher levels lead to beta cell death. Toxins like this that interfere with insulin signalling could promote diabetes development by interfering with the growth of beta cells (Hettiarachchi et al. 2006b).

Cereulide, a toxin produced by a bacteria linked to food poisonings, is toxic to beta cells (Vangoitsenhoven et al. 2015; Virtanen et al. 2008). At low levels, it causes beta cell death, and at even lower levels, impairs beta cell function (Vangoitsenhoven et al. 2014).

Colin and his family unknowingly moved into a home infested with toxic mold in 2001. Several years later, the family's dog developed diabetes. In 2007, the family discovered and attempted to remove the mold, resulting in a high levels of mold toxins throughout the house. Six weeks later, Colin was diagnosed with type 1 diabetes. He was 7 years old. 

His mother, Andrea, believes the mycotoxins released by toxic mold triggered both cases of diabetes. Read more at www.moldrecovery.blogspot.com. Andrea has since founded www.momsaware.org to raise awareness about environment and health.


To see studies on microbial toxins and diabetes, see this collection in PubMed: Microbial toxins and diabetes/obesity.