Understanding the Risks: What are the downsides of mycoprotein?

October 5, 2025 •

5 min read

While mycoprotein is often lauded as a sustainable and nutritious protein source, it has been linked to severe adverse reactions in some consumers. This raises a critical question for many: what are the downsides of mycoprotein? Understanding these potential risks is essential for anyone considering adding this fungi-based food to their diet.

Quick Summary

Mycoprotein, derived from a fungus, can trigger adverse reactions like allergies and gastrointestinal issues. Other potential drawbacks include elevated purine levels and the presence of added ingredients in processed products.

Key Points

Allergic Reactions: Mycoprotein, derived from a fungus, can trigger allergic reactions ranging from mild rashes to severe anaphylaxis, especially in individuals with pre-existing mold sensitivities.
Gastrointestinal Distress: The high fiber content of mycoprotein can cause common side effects like nausea, vomiting, and diarrhea, particularly in people with sensitive stomachs or IBS.
Elevated Uric Acid: Due to its purine content, mycoprotein could increase serum uric acid levels, posing a risk for individuals with gout.
Potential Additives: Many mycoprotein products use additives like egg whites as binders, which can introduce additional allergens not related to the mycoprotein itself.
Transparency Concerns: Historical issues with transparent labeling have led to changes, but consumers should remain aware of mycoprotein's fungal origin.
Not for Very Young Children: The high fiber and relatively low energy value make mycoprotein-based foods unsuitable for children under three years old.

Allergic and Hypersensitivity Reactions

Perhaps the most significant and severe downside of mycoprotein is its potential to cause allergic reactions, which can range from mild to life-threatening. Mycoprotein is derived from the Fusarium venenatum fungus, a fact that has raised concerns among consumer advocacy groups like the Center for Science in the Public Interest (CSPI). Some individuals, particularly those with pre-existing mold allergies, may experience cross-reactivity to mycoprotein.

Symptoms of a mycoprotein allergy or intolerance can include:

Hives or rash
Swelling of the eyes, tongue, mouth, or throat
Tingling or itching in the mouth
Breathing difficulties or asthma attack
Anaphylaxis, a severe, potentially fatal allergic reaction

Importantly, reactions have been reported to occur on a person's first exposure, suggesting that the body may confuse mycoprotein proteins with other similar fungal allergens. Due to pressure from consumer groups, labels on products containing mycoprotein are now required to mention that it is a mold and can cause rare allergic reactions.

Gastrointestinal Issues and High Fiber Content

For many consumers, the most common side effects of mycoprotein are gastrointestinal. Symptoms such as nausea, vomiting, diarrhea, and abdominal cramps are frequently reported. One of the primary causes of these digestive issues is mycoprotein's very high fiber content. While high fiber is beneficial for most people, some individuals may have a sensitivity to certain fermentable carbohydrates, leading to digestive distress.

High Fiber Fermentation: The dietary fiber in mycoprotein, which consists of chitin and β-glucan, is easily fermented by gut bacteria. This rapid fermentation in the large intestine can produce gas and lead to discomfort, particularly in those with a sensitive digestive system or conditions like Irritable Bowel Syndrome (IBS).
Delayed Gastric Emptying: Some research indicates that the mycoprotein matrix may delay gastric emptying, which can contribute to feelings of bloating and nausea.

Concerns for Individuals with Gout

Mycoprotein contains purines, which are compounds naturally found in many foods and are broken down in the body into uric acid. For individuals with gout, a form of arthritis caused by an excess of uric acid, a high-purine diet can be problematic. While the production process for mycoprotein includes a heat treatment to reduce nucleic acid levels and thus, purines, it is not completely removed. One study noted that a high-nucleotide mycoprotein diet led to a temporary increase in serum uric acid levels. Therefore, those with a history of gout or high uric acid levels should approach mycoprotein consumption with caution.

Additives and Cross-Contamination

Many commercial mycoprotein products, such as those from the brand Quorn, are not solely made of mycoprotein. To achieve a palatable texture and flavor, they often include additional ingredients. For instance, many Quorn products use egg whites as a binder, and some contain milk or gluten. This means that individuals with sensitivities or allergies to these common ingredients must check labels carefully. The inclusion of flavorings and other artificial ingredients to improve taste and texture also impacts the product's overall nutritional purity.

Historical Context: Marketing and Transparency

For many years, the marketing of mycoprotein was a point of contention. Early campaigns for Quorn, the most prominent mycoprotein brand, used phrases that suggested a close relation to mushrooms, which is botanically inaccurate. Critics argued this misled consumers about its true fungal origin and downplayed the risk of allergic reactions. A 2017 settlement required clearer labeling in the US, acknowledging that mycoprotein is a mold and has caused rare allergic reactions. This history highlights the importance of transparency regarding novel food ingredients and their potential risks.

How to Mitigate Potential Downsides

For those who wish to try mycoprotein despite the potential downsides, several strategies can help minimize risk:

Test your tolerance: Start with a very small portion to gauge how your body reacts. Wait a day before trying it again.
Read labels carefully: Always check the ingredient list for potential allergens like eggs, milk, or gluten, and be aware of the fungal origin. For additional guidance, authoritative bodies like Anaphylaxis UK provide resources.
Limit intake: If you are sensitive to high-fiber foods, moderating your portion size can help prevent digestive upset. Some individuals with IBS may need to avoid it completely.
Consult a doctor: If you have known allergies, gout, or a sensitive digestive system, speak to your physician before incorporating mycoprotein into your diet.

Mycoprotein vs. Other Protein Alternatives: A Comparison


Feature	Mycoprotein	Soy Protein	Pea Protein
Allergenic Potential	Potential for severe allergic and mold cross-reactions in sensitive individuals.	One of the most common allergens; widely recognized and labeled.	Generally considered low-allergenic; can be a good option for those sensitive to soy.
Gastrointestinal Issues	High fiber content can cause nausea, bloating, and diarrhea in sensitive individuals.	Can cause bloating and gas for some; typically dependent on processing and quantity.	Generally well-tolerated, though some may experience bloating due to fiber content.
Purine Content	Contains purines, which can increase uric acid levels for those with gout.	Contains purines; however, less concentrated than in meat.	Typically low in purines, making it a safer choice for individuals with gout.
Additives/Processing	Often uses egg whites as a binder; processed to achieve meat-like texture.	Highly processed into various forms like tofu, tempeh, or textured protein.	Can be highly processed into isolates and concentrates, but often simple in nature.
Environmental Impact	Generally very low carbon, land, and water footprint compared to animal meat.	Generally low impact; however, some concerns exist over monocropping and sustainability.	Environmentally friendly crop; requires less water and land than soy.

Conclusion: Is Mycoprotein Right for You?

Mycoprotein offers several benefits, including a low-fat, high-fiber nutritional profile and a very low environmental impact compared to meat. However, the reported allergic and gastrointestinal reactions are serious considerations, even if they are statistically rare. For most people, mycoprotein is likely a safe and healthy addition to the diet. But for those with allergies to mold, a history of gout, or a sensitive digestive system, the potential downsides may outweigh the benefits. As with any novel food, a cautious approach, careful label-reading, and awareness of your body's reactions are the best way to determine if mycoprotein is a suitable choice for your nutritional needs.

Frequently Asked Questions

Yes, some individuals can experience allergic reactions to mycoprotein, which is made from a fungus. Symptoms can include hives, swelling, breathing difficulties, and in rare cases, anaphylaxis.

Some people find mycoprotein difficult to digest due to its high fiber content. This can lead to gastrointestinal issues like nausea, bloating, diarrhea, and cramps, especially in those with pre-existing sensitivities.

Mycoprotein contains purines, which are broken down into uric acid in the body. For individuals with gout, a high-purine diet can be a concern, and mycoprotein consumption should be approached with caution.

Many commercial products containing mycoprotein are not pure fungal protein. They often include binders like egg whites, as well as flavorings and other ingredients, which should be considered by those with food allergies.

While generally safe for most, mycoprotein is not safe for everyone. Individuals with mold allergies, a history of gout, or a sensitive digestive system should be aware of the potential risks.

It is recommended to start by consuming a very small amount of mycoprotein. Observe your body for any adverse reactions, such as digestive upset or allergy symptoms, before consuming a larger portion.

Despite some health downsides, mycoprotein production has a significantly lower environmental impact in terms of carbon emissions, land use, and water consumption compared to animal-based proteins like beef and chicken.