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8 Surprising Negative Health Effects of Mold + Prevention

Written by Puya Yazdi, MD | Last updated:
Medically reviewed by
SelfDecode Science Team | Written by Puya Yazdi, MD | Last updated:

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Mold exposure has been linked to headaches, allergies, irritation, and all kinds of other health problems. Learn more about the negative effects of mold here.

What is Mold?

Molds are fungi. They can grow inside houses or other buildings, and some researchers and doctors believe that exposure to mold can cause health problems. The harmful effects of mold can be caused by exposure to mold directly, mold odor, mold byproducts, or dampness.

Harmful Effects of Mold

Headaches, fatigue, allergies or other unexplained symptoms are sometimes associated with the amount of time spent in a specific building or room. Some call this “Sick Building Syndrome,” and some researchers have attributed it to mold exposure [1, 2].

1) Respiratory Damage

Breathing mold or mold-derived byproducts into your lungs can be harmful in a variety of ways.

A meta-analysis showed that building dampness and mold increase the incidence of respiratory infections and asthma by 30 – 50% [3].

A similar study on residential home dampness and mold showed an 8 – 20% increase in the incidence of respiratory infections and bronchitis [4].

In children, exposure to indoor mold was associated with up to 50% more coughing. Moreover, stronger effects were seen for asthma in more crowded households [5].

A study on infants showed lung iron overload and lung bleeding disorders were significantly more abundant if they lived in homes with higher levels of fungi in the air and surfaces [6].

In buildings with water damage, respiratory illness was significantly associated with the presence of fungi and fungal metabolites [7].

Mold odor at home or work was associated with reduced lung function, especially in women [8].


Exposure to dampness and mold is associated with a significantly increased incidence of asthma [9, 10].

Asthmatic children living in mold-contaminated homes had a higher proportion of blood neutrophils compared to people who were not exposed to mold [10].

In patients with asthma, exposure to mold odor is associated with significantly reduced lung function [11].

In people who are allergic to mold, asthma is more common and much more severe [12].

2) Lower Quality of Life

The presence of visible mold in the home was associated with a worse quality of life, as measured by taking more sick days – both physical and mental [13].

Also, in patients with asthma, exposure to workplace dampness and mold was associated with a reduced quality of life [14].

3) Kidneys and Liver

Mold produces toxic byproducts including aflatoxin, ochratoxin, orellanine, and zearalenone.

  • Orellanine is capable of inducing serious kidney harm to the point of kidney failure in humans and animals [15, 16].
  • Aflatoxins, ochratoxins, and zearalenone have been identified as potential cancer-causing agents [17, 18, 19].
  • Aflatoxins and zearalenone may cause liver damage [19, 20].
  • Ochratoxins can strain the kidneys and the immune system [19].

4) Eye, Nose, Throat, and Skin Inflammation

A questionnaire study was performed with 36,541 randomized parents. It found that moldy homes were associated with inflammation in the eyes, nose, throat, and skin [21].

A study was done measuring reported symptoms and indoor air quality by teachers in New York State [22].

Reported mold or mold odors were associated with a 70% increase in reporting one of the following symptoms [22]:

  • Sinus problems
  • Headache
  • Allergies/congestion
  • Throat irritation

In another school study, mold or water damage was associated with respiratory infections, eye irritation, nasal congestion, and sore throat [23].

5) Headaches and Fatigue

In a questionnaire study of 36,541 parents, moldy homes were associated with headache and fatigue in the people who lived in them [21].

6) A Link to Autoimmunity?

In one study with 209 people, abnormally high levels of antibodies were found (ANA and antibodies against myelin) in people exposed to mold. The researchers who made this observation argued that mold may, therefore, be associated with lupus and multiple sclerosis [24]. However, this study had poor design and selection bias.

One Swedish study of 7500 participants found that people were up to twice as likely to have eczema in buildings with mold odor, condensation, and high humidity [25].

Another American study of 8400 people also found that people were close to twice as likely to have eczema in building with a musty odor [26].

Saccharomyces cerevisiae is a common species of yeast sometimes called baker’s or brewer’s yeast. While not a mold, it is a fungus. One study argues that S. cerevisiae presents the closest evidence we have linking fungi to autoimmune disease [27].

A growing number of studies have detected high levels of anti-S. cerevisiae autoantibodies (ASCAs) mainly in patients with Crohn’s, but also antiphospholipid syndrome, systemic lupus erythematosus, type 1 diabetes mellitus, and rheumatoid arthritis [28].

Antibodies against S. cerevisiae were found in 60–70% of patients with Crohn’s disease, and 10-15% in ulcerative colitis compared to 0-5% in healthy people [29].

Some researchers believe that a protein in yeast is similar to proteins in our body, and the immune system can get “confused” and start attacking its own, similar proteins [28].

A Link to Alzheimer’s?

One study laid out 7 case reports of people who had Alzheimer’s or Alzheimer’s-like symptoms, which they believed may have been associated with various strains of mold found in their houses [30].

However, there is no well-documented link between Alzheimer’s disease and mold. This is simply the early speculation of a single author.

Susceptibility to Fungal Infections

Exposure to fungi or spores can lead to systemic fungal infection, also known as mycosis [31].

This is more common in people with compromised immune systems, for example, systemic lupus erythematosus, who are more likely to get certain fungi infections [32].

One study showed an increased incidence of mycosis in alcoholic liver disease patients, which was further associated with increased mortality [33].

The use of antibiotics, pregnancy, diabetes, and HIV/AIDSare linked to vaginal yeast infections, whereas clothing and personal hygiene do not appear to have an effect [34].

Both athlete’s foot and toenail fungus are more prevalent with increasing age, male gender, and type 2 diabetes [35].


If your home or office has taken on water or flooded, remediation should be rapid and complete. Everything should be thoroughly dried and may need to be removed if mold is already present [36]. Mold can develop within 48 hours of taking on water [37].

When in doubt, call a professional cleaning service. If you believe that mold exposure has caused health problems for you or someone close to you, seek medical attention.

Do You Suspect Mold?

It’s very hard to pinpoint whether a certain health issue started as a result of mold or another underlying factor or health condition. There are other possibilities, such as air pollution, VOCs, carbon dioxide, environmental chemicals, radon, tobacco smoke, and airborne infections that could also cause someone to be sick.

If you suspect that mold plays a role in your health issues, talk to your doctor about this possibility. They will help you rule out other underlying factors and identify whether mold is the culprit.

About the Author

Puya Yazdi

Puya Yazdi

Dr. Puya Yazdi is a physician-scientist with 14+ years of experience in clinical medicine, life sciences, biotechnology, and nutraceuticals.
As a physician-scientist with expertise in genomics, biotechnology, and nutraceuticals, he has made it his mission to bring precision medicine to the bedside and help transform healthcare in the 21st century. He received his undergraduate education at the University of California at Irvine, a Medical Doctorate from the University of Southern California, and was a Resident Physician at Stanford University. He then proceeded to serve as a Clinical Fellow of The California Institute of Regenerative Medicine at The University of California at Irvine, where he conducted research of stem cells, epigenetics, and genomics. He was also a Medical Director for Cyvex Nutrition before serving as president of Systomic Health, a biotechnology consulting agency, where he served as an expert on genomics and other high-throughput technologies. His previous clients include Allergan, Caladrius Biosciences, and Omega Protein. He has a history of peer-reviewed publications, intellectual property discoveries (patents, etc.), clinical trial design, and a thorough knowledge of the regulatory landscape in biotechnology. He is leading our entire scientific and medical team in order to ensure accuracy and scientific validity of our content and products.

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