Functional mushrooms have had a big moment in the wellness world, and for good reason — the research behind certain species and their impact on immune function is genuinely compelling. But with so much marketing noise around "immune-boosting" products, it helps to look at what the science actually says and which mushrooms are worth paying attention to.
Here's what we know about the best mushrooms for immune support, and how to get the most out of them.
Why Mushrooms? The Beta-Glucan Connection
The primary reason mushrooms are studied for immune health is beta-glucans — a type of polysaccharide found in the cell walls of fungi. Beta-glucans are classified as biological response modifiers, meaning they interact with the immune system in ways that help it function more effectively.
Specifically, beta-glucans bind to receptors on immune cells like macrophages and natural killer cells, helping to "prime" these cells for a more effective response. This isn't the same as "boosting" immunity in a vague, unscientific sense — it's a specific mechanism that researchers have studied extensively.
Maitake: One of the Most Studied
Maitake (Grifola frondosa) is arguably the best-researched mushroom for immune function. It contains a particularly potent beta-glucan called the D-fraction, which has been the subject of numerous studies examining its effects on immune cell activity. Some research has also investigated maitake in the context of supporting conventional cancer treatments, though this research is ongoing and should not be interpreted as medical advice.
What's clear is that maitake is a genuinely functional food — one where the health benefits go beyond basic nutrition.
Lion's Mane: Brain Health and Beyond
Lion's mane (Hericium erinaceus) is best known for its potential cognitive benefits — specifically its ability to stimulate Nerve Growth Factor (NGF), which supports the maintenance and growth of neurons. But it also contains beta-glucans and polysaccharides that contribute to immune regulation.
Research suggests lion's mane may have anti-inflammatory properties and could support gut health, which is increasingly recognized as closely connected to immune function. A significant portion of the immune system resides in the gut, making gut-supporting foods an indirect but meaningful contributor to immune health.
Shiitake: Lentinan and Immune Function
Shiitake (Lentinula edodes) contains lentinan, a specific beta-glucan that has been studied extensively — particularly in Japan, where it has been used as an adjunct therapy in certain medical contexts. Shiitake also contains eritadenine, which may support cardiovascular health, and a full spectrum of B vitamins.
Eating shiitake regularly as part of your diet is one of the most accessible ways to incorporate immune-supportive mushrooms into your life. They're delicious, widely available, and cook beautifully in a huge range of dishes.
Oyster Mushrooms: Pleuran
Oyster mushrooms contain pleuran, a beta-glucan that has been studied for its immune-modulating effects. Research has shown that pleuran may help reduce the frequency and severity of upper respiratory tract infections — a practical, everyday immune benefit.
Oyster mushrooms are also one of the easiest functional mushrooms to eat regularly because they're so versatile and mild-flavored.
How to Get the Benefits: Eating vs. Supplements
Here's an important point: you don't necessarily need to buy supplements, extracts, or powders to benefit from functional mushrooms. Simply eating them regularly as part of a varied diet provides meaningful amounts of the compounds associated with immune support.
Cooking does not destroy most of the beneficial beta-glucans in mushrooms — they're heat-stable. Sautéing, roasting, simmering in soups — all of these preparation methods are fine. However, some research suggests that the bioavailability of certain compounds may be enhanced by hot water extraction, which is why mushroom teas and broths are a traditional preparation method in East Asian medicine.
A Note on Realistic Expectations
Mushrooms support immune function as part of a healthy lifestyle — they're not a cure for any disease and should not replace medical treatment. But as a regular part of your diet, the evidence suggests they offer meaningful, real-world benefits. Think of them as one of the most delicious ways to invest in your long-term health.
Get Your Functional Mushrooms Fresh from True Mycology
We grow maitake, lion's mane, oyster mushrooms, and other specialty varieties right here on Long Island. Fresh, locally grown mushrooms harvested close to when you buy them give you the best possible nutritional profile. Find us at Long Island farmers markets and follow us on TikTok for cooking inspiration and growing updates.
Eat your mushrooms. Your immune system will thank you.