Once relegated to the Asian foods section of grocery stores, shiitake mushrooms have emerged a prominent contender in the produce aisle, promising to add a little extra oomph – and even some medicinal benefits – to vegetable socks, soups and noodle dishes.
Although this fungi is an excellent source of selenium and a good source of iron, protein, dietary fiber and vitamin C, shiitake mushrooms are much more revered for their combination of antioxidants and other compounds, so much so that they have been used in Asian medicine for the past 6,000 years!
Specifically, shiitake mushrooms contain a polysaccharide known as lentinan that is thought to shore up the immune system, particularly in people who have a compromised immune system due to HIV, AIDS or other immunodeficiency disorders. In addition, lentinan has also been shown to offer a protective benefit against certain cancer types by increasing the population of reticular cells (a type of immune cell that actively seeks out and ingests bacteria, cancer cells and other cell waste) and drawing T lymphocytes (another immune system heavy hitter) to prevent cancer cell proliferation.
In addition, mushrooms are also an excellent source of L-ergothioneine – containing roughly 13 mg per 3 oz serving – or about forty times the amount of top L-ergothioneine heavy hitter wheat germ. What’s the big deal about L-ergothioneine? Well, this powerful antioxidant – which is only available via dietary resources – is thought to play a key role in both energy regulation and in protecting cells from free radicals and their associated oxidative damaging (think wrinkles, skin damage, and general aging of the entire body). Even better news? L-ergothioneine remains intact in mushrooms during cooking.
But are there any drawbacks to indulging in your favorite fungi? Well, yes. It should be noted that shiitake mushrooms contain a naturally-occurring compound known as purines that can cause excess accumulation of uric acid in the body, which in turn can lead to gout or the formation of kidney stones. However, this is generally not a problem for the majority of the population and shiitake mushrooms – and other sources of purines – should only really be of concern to those already suffering from kidney problems or gout.
When selecting shiitake mushrooms (a name that can be interchanged for similar reishi and maitake mushrooms), look for those that are firm, plump and clean with no dark spots or “bruises.” Since the mushrooms are porous, they should be refrigerated in a paper bag – where they can stay fresh for about a week – and cleaned before preparation only with a damp paper towel (as opposed to being rinsed or submerged in water, which can cause them to become soggy). However, if you find that your mushrooms have become dried out during storage, placing them in a bowl of water for 30 minutes can do wonders to revive them!