Smart Fuel: Mushrooms

Assortment of mushrooms

Neither plant nor animal, the mushroom usually gets lumped in with the former but genetically it’s closer to the latter. In fact, mushrooms and people are members of the same biological superkingdom, Opisthokonta, which excludes plants; we shared a common ancestor with fungus about 600 million years ago. But while mushrooms are an odd genre of organism, that’s nothing compared to what lies beneath and supports them. The mushroom is just the fruiting body of the underground network of fungal threads known as the mycelium.

What’s so interesting about the mycelium?

It’s been called the “natural Internet,” transmitting data along its fibers using the very same neurotransmitters (serotonin, melatonin, and others) we mammals use to think thoughts. Other fungal transmitters, like psilocybin and psilocin from “magic mushrooms,” are similar enough to serotonin that they’re able to interact with our serotonin receptors and produce mystical, psychedelic experiences when we eat them.

It can break complex structures into simpler compounds. Certain mycelia have been shown to break down plastics and petroleum products, pesticides, and other contaminants into their constituent, less-toxic parts.

It’s enormous. A single mycelium network can cover thousands of acres, making it the largest single organism on Earth.

It participates in a kind of marketplace, extracting nutrients from the soil, transforming them, and using them to barter with plants for energy derived from photosynthesis. In this way, it supports the entire plant kingdom.

If you’re interested in this stuff, Paul Stamets is the go-to mycelium guy. His TED talk from a few years back is incredible, as is his book Mycelium Running: How Mushrooms Can Save the World.

Okay, okay. That’s interesting enough, but are mushrooms good to eat?

Well, if you asked representatives from the hundreds of human cultures across the globe that have utilized wild edible fungus, the answer would be yes. Humans have probably always eaten mushrooms, since mushrooms grow wild everywhere. And I do mean everywhere. The barren North African desert has edible fungi (desert truffles). Even Antarctica’s got fungi. No word on their edibility, though.

Mushrooms may not be the richest source of the better known micronutrients – your magnesiums, calciums, vitamin Cs, vitamin B12s, vitamin As – but they’re good sources of relatively rare nutrients like selenium, copper, and pantothenic acid. Fresh mushrooms also enjoy sunbathing, synthesize a good amount of vitamin D in response to it that we can utilize and absorb when we eat them. You can even buy some mushrooms from the store, lay them out on a plate in the afternoon sun for a couple hours, and they’ll synthesize vitamin D. Cool, huh?

But the real interesting properties of mushrooms lie in the compounds that don’t appear in FitDay or the USDA nutrient database. Many, perhaps most edible mushrooms contain substances with therapeutic, medicinal, or otherwise pharmacological effects. Let’s look at a few of them:


Shiitakes are denser, heavier, and higher in protein and iron than most other varieties. They’re also more expensive, but they’re probably worth it for the potentially therapeutic compounds:

L-ergothioneine is an antioxidant cytoprotectant, meaning it protects cells from oxidative damage. Some researchers think it might “represent a new vitamin” because it can only be obtained through diet. Shiitakes are by far the best source of L-ergothioneine.

Lentinan is a shiitake polysaccharide with anti-tumor and immune boosting effects. In people with depressed immune systems, lentinan can provide a needed increase.


Don’t be fooled by its near paucity of mainstream nutrients. In animal models of arthritis, the lowly white button mushroom reduces the severity. It also elicits a heightened immune response, but only when co-administered with an immune insult (lipopolysaccharide/endotoxin). Simply feeding a mouse lots of white button mushrooms without giving it a reason to require an immune response has no effect (and rightly so). Also, high consumption of button mushrooms has been inversely linked to ovarian cancer in women.


Criminis are young, nubile portobellos. Portobellos are actually just old, crotchety criminis. And both criminis and portobellos are the same species – agaricus bisporus – as the white button mushroom. So everything mentioned in the last section applies here, too. As for portobellos, they’re famous for “replacing” meat in burgers and sandwiches, but I like portobello mushrooms much better with meat. How about instead of switching out the beef patty for a portobello, we replace the buns with the portobellos?


Ah, man, nothing like a chanterelle sliced and cooked in some broth and butter. It can really make a man overlook the lack of solid research into the mushroom’s health benefits. Eh, some vitamin B12 that may or may not be inactive and preliminary in vitro indications of chemoprevention are good enough for me!


Porcini mushrooms are invaluable when cooking Italian food, so it’s okay that there’s not much solid evidence for miraculous health benefits. They do, however, help hypertensive rats manage their blood pressure and improve the metabolic abnormalities often associated with hypertension.


They appear on tree trunks, require delicate handling to avoid breaking, and may (big “may”) mimic nerve growth factor enough to stimulate the formation of new synapses. Oyster mushrooms also show anti-candida activity and contain a wealth of antioxidant compounds.

Lion’s Mane

I wrote about this already, but it tastes like lobster and could potentially improve your cognition, so I’m going to reiterate. Lion’s Mane usually comes dried and may reverse mild cognitive decline in the elderly, help people with nerve damage regenerate destroyed nerves and regain their ability to walk, and act as a nootropic in healthy people.

As you can see, every mushroom people have looked into seems to be good for us. And there are some commonalities that keep appearing: some interaction with nerve growth factor, cognitive function, immune function; a host of antioxidant compounds. Great in omelets, perfect alongside a steak, and ideal for boosting the immune system.

A few tips:

  • Cook them. Fungal cell walls are made of chitin, the same “fiber” found in insect carapaces. Chitin can be difficult to digest, but heat breaks it down, making the mushroom easier to digest and unlocking the nutrients. A sautéed mushroom also just tastes really, really good.
  • A real simple, foolproof way to cook mushrooms (any mushroom I’ve come across) is to slice them and saute in butter and/or olive oil for about five minutes, or until they begin to soften and darken. Then you add a few dashes of Worcestershire sauce, a few dashes of balsamic vinegar, some red wine, or maybe some good beef or chicken stock. Anything that you can reduce will work. Reduce that down over low heat until the sauce gets syrupy. Sprinkle sea salt and cracked black pepper to taste.
  • I suggest checking out the dried mushroom aisle of an Asian grocery. Those are great to add to soups and stews (no rehydration required), and there are just so many interesting kinds to choose.
  • And go to the local farmer’s market. There’s usually a mushroom guy there with dozens of varieties that you’d never find in a grocery store. He can tell you what they taste like, how to cook them, and what to expect from them because he most likely cultivated them. Make friends with the mushroom guy.
  • Wild edible mushrooms abound, but so do poisonous varieties. To avoid getting sick, contact your local Mycological Society; they’re also everywhere. They’ll set you up with guided shroom-hunting tours with local experts, so you know what to look for and what to avoid. You might also check for a mushroom hunting group near you.
  • If you want to grow your own, I suggest checking out the Shroomery forums. Its members focus on cultivation of psychedelic species, but they’re also very knowledgeable about edible cultivation. There’s also a good board dedicated to mushroom hunting and proper identification where you can provide photos and a description (following a template provided by the regulars) and get expert opinions on whether the mushroom you picked is deadly or delicious.

I hope this post has piqued your curiosity and your appetite. It’s long overdue that we start incorporating more mushrooms into our Primal way of eating.

What’s your favorite type of mushroom and how do you like to cook it?

TAGS:  smart fuel

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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