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Cannabis poses health risks due to harmful fungi that often contaminate the plants

Cannabis, a plant often acclaimed for its potential therapeutic effects, may actually be causing some users to fall ill. A recent study reveals that cannabis use – even for medical purposes – could make some people sick due to harmful fungi that contaminate the plants.

The research was led by Kimberly Gwinn, a professor of Entomology and Plant Pathology at the University of Tennessee Institute of Agriculture

Eye-opening research

The team examined data, previous studies, and international regulations related to the cannabis and hemp industry in the United States.

Ultimately, the researchers found that the contaminants present in cannabis and hemp flowers could pose significant health risks, especially for those with compromised immune systems. 

The experts strongly advocate for a more in-depth investigation and reevaluation of the standards set for the medical use of cannabis.

Research gaps

“Hemp and cannabis are new crops, and we are in the early stages of understanding relationships with their pathogens,” noted Professor Gwinn.

“Several pathogens produce mycotoxins, compounds that negatively impact human health and are regulated in other crops.”

“In this review, we summarize the current literature on mycotoxins in hemp and cannabis products, identify research gaps in potential mycotoxin contamination in hemp and cannabis, and identify potential developments based on research in other crop systems.”

Focus of the study

For the investigation, Professor Gwinn collaborated with Maxwell Leung and Ariell Stephens from Arizona State University, and Zamir Punja from Simon Fraser University in British Columbia.

Cannabis research has mostly focused on the substance and medical uses of the plant, but with the increased legalization of cannabis for various uses, this article addresses the need for more study of potential health risks.

“Although fungi and mycotoxins are common and well-studied contaminants in many agricultural crop species, they have been generally under-studied in cannabis and hemp. This is partly because human health risk assessment methodologies used to regulate food and pharmaceuticals have yet to become standard for the emerging cannabis and hemp industries,” wrote the study authors.

“Additionally, the wide range of consumer uses of cannabis and hemp flowers, including for medical use by patients with susceptible conditions, makes it uniquely challenging to assess and manage human health risk of these contaminants.”

Cannabis risk from harmful fungi

The research sheds light on various fungi such as Aspergillus, Penicillium, Fusarium, Mucor, among others, that can infect the plants and produce harmful mycotoxins. 

The location where these plants are cultivated, whether indoor or outdoor, and the medium in which they grow, whether soil or soilless, play a crucial role in determining the type of contaminants and the associated health risks.

According to the studies examined by the researchers, some fungi can lead to infections in lung and skin tissues, with infections being more common in smoked cannabis than in edibles. 

Caution urged for some groups

Certain groups, including cancer patients using cannabis for nausea relief, organ transplant recipients, HIV patients, and those with type 1 diabetes, may be especially vulnerable. The researchers also identified risks for those involved in the harvesting of cannabis.

Given the lack of comprehensive data on the prevalence of these contaminants – along with the varying state-to-state legalization levels and regulations of cannabis products – consumers face some important unknowns. 

Implications of this risk from cannabis

The study identifies challenges in testing for pathogens using methods like culture-based assays, immuno-based technologies, and more advanced techniques. 

The experts emphasize the critical need to bridge the gap between production issues and human safety concerns in the cannabis and hemp industries.

“We wrote this article to bring these issues to the attention of the scientific, medical, and regulatory communities,” said Professor Gwinn.

“We hope to encourage further research in this area, particularly in the areas of mycotoxins in product. Better data and public access to data will allow us to fully evaluate these risks and subsequently ensure safe products for consumers.”

The full study is published in the journal Frontiers in Microbiology.

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