It is well established that exposure to mold increases the risk for respiratory disorders [1], but could it also impact brain health and the risk for cognitive decline? While there have been no conclusive epidemiological studies linking mold exposure to dementia, there is evidence from case studies to suggest that mold exposure may contribute to cognitive impairment in a subset of susceptible people [2].
It has been difficult to establish whether there is a direct link because not every person who is exposed to mold will experience cognitive symptoms. Instead, it appears that there is only a small subset of people who will be affected. Unfortunately, there is currently no way to identify this vulnerable subset before they show symptoms. No specific type of mold or level of exposure has been associated with increased risk for cognitive symptoms [3]. Several possibilities have been put forth to try to explain how mold exposure could affect cognition, which may provide some insight into why some people are at higher risk.
Exposure to mycotoxins: Some types of mold are capable of producing toxic substances called mycotoxins. Studies in animals have shown that some of these toxins can get into the brain and cause damage by interfering with metabolism and inducing inflammation [4]. It is possible that it is exposure to the mycotoxins rather than the mold itself that leads to cognitive symptoms, which may explain why only a subset of people develop cognitive symptoms following mold exposure.
Inflammation: Mold spores act as irritants, which can trigger the body to mount an immune response. This can lead to inflammation throughout the body. Inflammation in the brain can impair cognitive function, and in the case of chronic inflammation, this can lead to long-lasting cognitive impairment. It has been suggested that differences in the response to mold exposure may be related to the way the immune system responds in a given person [5]. From this perspective, the people who develop brain inflammation following mold exposure are the ones most likely to experience cognitive decline. People who experience inflammation and delirium following mold exposure appear to be at the highest risk for long-lasting cognitive impairment [2].
Stress: Chronic exposure to mold is typically associated with stressful conditions, such as low socioeconomic status, or water damage to one’s home or workplace [4]. Stress can also cause inflammation. Therefore, some of the negative health effects from mold exposure, including cognitive effects, could arise from the body’s response to stressful conditions, rather than the mold itself.
WHAT YOU CAN DO
There are currently no tests available to accurately predict who will experience negative effects to their brain health following mold exposure. Many different strains of mold are capable of producing mycotoxins, but the presence of one or more of these strains does not guarantee that mycotoxins are also present, or that someone who comes in contact with the mold has been exposed to mycotoxins [4]. Tests measuring mycotoxin levels in the blood and urine have been developed, however, they do not convey the level of mycotoxins or associated inflammation in the brain, which may explain why these tests have not been useful for predicting mold-related cognitive impairment [6]. New tests that assess the immune response to mold are being developed, but need further validation [7].
The two major routes of exposure to mold and mycotoxins are through the environment, such as buildings, and the food supply.
Food: It is important to avoid eating food that shows visible signs of mold growth. The FDA regulates the level of mycotoxins in the commercial food supply, so the greatest risk comes from locally grown food that is not subject to inspection [8].
Buildings: Mold grows best in areas that are warm and damp, and is most common in buildings that contain leaks or have high humidity, carpeting, and poor ventilation. The CDC has issued guidelines for how to avoid mold in the home, such as repairing leaks, keeping humidity levels low, and improving ventilation systems [9]. Once mold is present, the CDC recommends removing any carpet that has gotten wet, and thoroughly cleaning contaminated surfaces with a bleach solution (1 cup of bleach in 1 gallon of water) while maintaining proper ventilation, such as by opening a window.
It is important to treat all mold as potentially harmful to brain health by taking precautions to avoid it and seeking medical attention if symptoms develop following exposure.
Betsy Mills, PhD, is a member of the ADDF's Aging and Alzheimer's Prevention program. She critically evaluates the scientific evidence regarding prospective therapies to promote brain health and/or prevent Alzheimer's disease, and contributes to CognitiveVitality.org. Dr. Mills came to the ADDF from the University of Michigan, where she served as the grant writing manager for a clinical laboratory specializing in neuroautoimmune diseases. She also completed a Postdoctoral fellowship at the University of Michigan, where she worked to uncover genes that could promote retina regeneration. She earned her doctorate in neuroscience at Johns Hopkins University School of Medicine, where she studied the role of glial cells in the optic nerve, and their contribution to neurodegeneration in glaucoma. She obtained her bachelor's degree in biology from the College of the Holy Cross. Dr. Mills has a strong passion for community outreach, and has served as program presenter with the Michigan Great Lakes Chapter of the Alzheimer's Association to promote dementia awareness.
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