For the last 30 years Paul Stamets has collected, cultivated, studied and written about mushrooms. He’s the founder of Fungi Perfecti, a company that sells a variety of mushroom-related products, including kits for growing edible mushrooms. He’s also written several books, including Growing Gourmet and Medicinal Mushrooms, and Mycelium Running: How Mushrooms Can Help Save the World.
Yep, you read that right: Stamets’ new book tells us how mushrooms can help save the world. If that idea sounds like a stretch, prepare to have your mind expanded. Stamets has done extensive research on the practical ways people can use mushrooms to heal ourselves and protect the planet. That includes studying mushrooms’ nutritional properties (many types are a great source of Vitamin D, among other vital nutrients), and their potential for developing new medicines (some species show promising antibacterial and antiviral properties) and cleaning up the environment (fungi can be used to help clean up oil spills and other types of soil and water contamination).
Stamets took the time to answer our questions about the health and environmental benefits of mushrooms. Here’s what he had to say about the fantastic world of fungi.
Mushrooms, Mycelium and the Planet
Your latest book is called Mycelium Running. First, what is mycelium exactly?
Mycelium is a network of fungal cells threaded together to form long, forking chains, creating a complex fabric of cells permeating virtually all land masses of Earth, from the tundra to the tropical rainforests.
How is mycelium related to mushrooms?
Mycelium is threadlike, but bundles up to form the structure of the mushroom, what we call the “fruiting body.” First the mycelium needs to dominate a territory, and only then does it pull its nutritional resources together to begin the construction of a mushroom.
You've written a lot about mushrooms being used for bioremediation, or naturally breaking down toxic compounds in the water and soil. What are some of the ways that mushrooms have been used to clean up polluted sites?
The mycelium of mushrooms are unique in their wood-decomposing enzymes, especially cellulases (which break down cellulose) and lignases (which break down lignin). Cellulose is the fibrous part of woody plants while lignin is the blocklike structure which the cellulose encases. These powerful enzymes are molecular disassemblars of not only plants, but complex chemicals.
There are dozens of examples of how mushrooms can be used for bioremediation, what we call “mycoremediation.” Mycelium of oyster mushrooms (Pleurotus ostreatus) can eat petroleum products, denaturing them, and the mycelium converts the hydrocarbons into cellular carbohydrates. Examples include using mycelium to break down oil, dioxins (and PCBs), as well as nerve gas toxins.
What happens to the mushrooms after you've used them to clean up toxins? Are they safe to eat or do they need to be disposed of carefully?
To the best of our knowledge — and I must emphasize that more studies are needed — it appears the mushrooms coming from oil-contaminated soils are edible. However, a major problem is that with oil spills, heavy metals and other toxins also co-occur, so it is safer to let the mushrooms rot and return into the soil food web rather than cooking them for dinner.
You're also working on a project where people are using mushrooms for water filtration. What can you tell us about that?
Mycelium can be grown on woodchips and placed into burlap sacks to filter water run-off, which can contain petroleum products, heavy metals and toxic bacteria. Mycelium Running describes these methods in great detail.
We are involved in several projects here in Mason County, Wash., connecting the Soil Conservation District; the Public Works Department, which chips wood from storm-damaged branches and trees; and the Health Department, which has a mandate to protect the watersheds and estuaries. We are seeking partners to conduct experiments nationally this next year.
You write that one of the ways that mushrooms might save us is by treating viruses. Is it really possible that antiviral properties in mushrooms might be used to treat viruses such as bird flu?
Yes, my work on novel antiviral and antibacterials from mushrooms has produced some surprising results: results which are reproducible, species-specific and out-performing in some instances, the pure control antiviral drugs when run in parallel. Thus far, these are in-vitro tests — some of the best modern tests science has developed to discover possible new medicines.
But, as we all know, in-vitro tests must be confirmed in-vivo, in animals (humans) before we know for sure. It’s especially interesting that these mushrooms show antibacterial as well as antiviral properties because to treat some diseases you need both. For instance, many if not most of the victims from the flu pandemic of 1918, died from bacterial pneumonia subsequent to the viral scarring of their lungs.
Viruses not only challenge the immune system, but they reduce your defenses, making you more susceptible to other diseases. Moreover, mushrooms have immuno-modulating and anti-inflammatory properties that can help the immune system respond without going haywire. This area of research is very dynamic, currently, and we have high hopes for identifying a consortium of new fungal based active ingredients in 2009. At this point in time, it appears the beneficial compounds work synergistically. Mushrooms proffer a composite menu of benefits helping you stave off diseases.
In your book you give a long list of diseases that mycomedicines might be used for, including not only influenza, but also HIV and cancer. If we find an amazing new medicinal use for mushrooms what happens next? Are there issues with overharvesting valuable wild mushrooms?
Our research on the antiviral properties of mushrooms shows that the mycelium is a better source than the mushrooms themselves. Hence, new mycomedicines are best grown in laboratories, under strict conditions. This will assure purity. However, all strains come from nature, and we need to screen as many wild strains as possible to find the most potent ones and to ultimately find the gene sequences responsible for their expression.
I am concerned about the over-harvesting of wild mushrooms, particularly rare species in increasingly threatened ecosystems. I have a library of strains, many obtained from now-destroyed habitats, in the hope that these will prove valuable.
Cooking and Eating
You've done a lot of work with the nutritional content of mushrooms. Should we all be growing mushrooms in our backyards?
Many beneficial, nutritional and immune enhancing properties are gained through the eating of cooked mushrooms. In Mycelium Running, I outline methods of growing mushroom species in your backyard, customized to the health needs of your family.
Is there any one type of mushroom that you think we should all be eating more of?
I think a combination of these mushrooms offer exceptional benefits: shiitake, maitake, enoki, oyster, nameko and lion's mane, but, only when they have been thoroughly cooked. Raw mushrooms offer little to negligible nutritional benefit since many of the nutrients are locked into the tough chitin-like cells which are the building blocks of the mushroom.
We're very interested in food sources of Vitamin D, because there’s a lot of new research suggesting we all need more of this nutrient. (For example, you can get it from eggs.) Studies have found that some types of mushrooms are a surprisingly good source of Vitamin D when they're exposed to UV light — either sunlight or artificial light. What can you tell us about your research in this area?
What is interesting about my research is the evidence that not only can normal, summer sunlight spike production of Vitamin D in fresh mushrooms, but that sun-exposure for dried mushrooms also provides a significant amount of Vitamin D, even if those mushrooms were picked months earlier during the fall or spring seasons, or grown indoors. One test with indoor-grown shiitake mushrooms, which had approximately 40 IUs of Vitamin D per 100 grams, spiked to more than 30,000 IUs after two days of summer sun exposure. But, after three days of about six hours of exposure per day, the accumulated Vitamin D begins to decline.
So, the take home lesson here is to take your stash of dried mushrooms and lay them out on a table in full sun for two days during the summer. (Interestingly, much more Vitamin D is produced when the mushrooms are dried with the gills facing up into the sun, rather than the cap). Repackage them for use later in the year. I like storing dried mushrooms in the freezer if you have room, or in Masonlike jars on a dark shelf, if you don’t have enough freezer space. Not only can these mushrooms provide you Vitamin D during the winter months, but they are delicious, nutritious, and offer a vegan-friendly source of this essential nutrient.
I've seen "Vitamin-D Enhanced" mushrooms for sale at the grocery store, which have been treated with artificial light. What do you think about those?
I think “Vitamin-D Enhanced” organically grown mushrooms are a good idea.
Most of us are worried about not getting enough Vitamin D, but mushrooms contain so much of this nutrient that in your book, you caution people about overdoing it. Is that something people should be thinking about when they eat mushrooms?
Most fresh mushrooms are about 90 percent water. If eating 3 to 4 ounces of fresh sunstroked mushrooms, my research shows that you would get about 4,000 IUs of Vitamin D2 in a meal. Dr. Andrew Weil and others now recommend around 1,000 IUs per day, or 7,000 per week. Having 10 grams of dried mushrooms (approximately 100 grams of moist mushrooms) twice a week would then give you about 8,000 IUs, very close to the recommended amount. Bear in mind that Vitamin D2 only stays in your bloodstream for two to three days. Realistically, I do not think you are in danger of overdosing on Vitamin D enhanced mushrooms if you eat them twice a week.
Most Useful Mushrooms
If you had to pick a single species that was the most useful, which would it be?
As an antiviral and antibacterial: Agarikon (Fomitopsis officinalis).
For food and environmental medicine: Oyster mushrooms (Pleurotus ostreatus).
What’s the most delicious mushroom you’ve run across?
Candy Caps (Lactarius fragilis) taste like maple syrup!
Is it difficult to grow your own mushrooms?
No, it’s just like riding a bike — once you know how to do it, mushroom cultivation is easy. However, some species are easier than others. Oysters, shiitake, pioppino, nameko, maitake, reishi and turkey tail are all easy to grow. Others are not. Fortunately we have a large cast of fungal characters to draw from.
What's one thing you think everyone should know about mushrooms?
Mushrooms and their mycelium guard the ecosystem, connect food chains, and are one of the primary pillars of the food web — recycling nutrients and playing a critical role in keeping the forests and fields healthy. Mushrooms and their mycelium are quiet allies that are essential for our healthy existence. They are enigmatic, have a sense of humor, and socially as well as spiritually, bond together all that admire them. They have much to teach us.
Looking for more information on mushrooms? You can find more about growing mushrooms here. Also, check out our article on hunting wild mushrooms and this list of mushroom field guides.
Megan E. Phelps is a freelance writer based in Kansas. She enjoys reading and writing about all things related to sustainable living including homesteading skills, green building and renewable energy. You can find her on Google+.