This week I read a great blog post on mycotoxins from the Aspergillus Website. There has been considerable debate regarding the health effects of airborne mycotoxins through the years. In this post I will hit the main points related to mycotoxins indoors.

Some species of fungi have the ability to produce mycotoxins. These toxins help inhibit the growth of other microorganisms around them. Because it takes vital energy for the cells to produce mycotoxins, they are not always produced all the time (they are secondary metabolites). This point is significant because it means finding mold on the wall doesn’t necessarily mean there are mycotoxins present.

There is no doubt that mycotoxins can cause severe health effects. I’ve spent a considerable amount of time in East Africa and it seems like every trip I make, there are a significant number of deaths due to mycotoxins. These deaths, however, are not from inhaling spores in water damaged buildings. These deaths are from ingesting food contaminated with mold growth and mycotoxins. Most studies related to mycotoxins are based on ingestion studies on animals. What about inhalation studies on humans?

Regulations on human subject research (and another thing called morality) prohibit the use of thorough human tests to establish a dose-response relationship. We know that mycotoxins are not volatile and found mostly on spores, growth structures, and the substrate. All three of these can become airborne, especially when the substrate is agitated or demolished. How many milligrams of mycotoxin in the air will cause health effects? That’s the million dollar question! Anecdotally, many people have experienced symptoms at low levels of exposure. Based on lab rat tests, others suggest the levels must be extremely high before reactions occur.

In future blog posts I’ll share more information on the sampling strategies, health effects and chemistry of mycotoxins.  Until then, I suggest you read this blog post from the Aspergillus Website titled Steps to Proving Inhaled Mycotoxins are Harmful to Human Health?