Packed with antioxidants and vitamins, mushrooms can support your brain and immune system. Photo / 123RF
Rich in plant chemicals and antioxidants, mushrooms are a delicious, nutritious powerhouse that everyone could benefit from eating more of.
Low in calories and fat but packed with vitamins, mushrooms are a nutritional force for good and a tasty addition to any plate. Earthy, meaty and comforting, they’re among the most versatile of ingredients you could find in your fridge. Just as healthy as the ubiquitous avocado – and certainly as good on toast.
Sautéed in olive oil and served on sourdough, or stirred into a creamy risotto or ragout, mushrooms are the only non-meat that comes close to a meaty texture, courtesy of the rich umami flavour that makes them unique among plants. They’re a remarkable and varied species, coming in all shapes and sizes – from chestnut to fan-shaped oyster mushrooms – and have long been held to have healing properties, thanks to their high quota of plant chemicals.
As clinical nutritionist Eva Humphries summarises, mushrooms are especially rich in protective antioxidants.
“Supermarket mushrooms have the potential to support various aspects of human health via their antioxidant content,” says Humphries. “Specific antioxidants in mushrooms may protect the liver from toxins, the brain from stress or they can give the immune system a leg up against viruses.”
Having a few extra mushrooms on your plate each day could certainly improve your nutrition in all kinds of ways. Here’s why.
In 2021, data from a large population study in the US revealed that people consuming the most mushrooms were likely to live longer. The study said one of the reasons for this was the beneficial nutritional composition of mushrooms: they’re low in calories, saturated fats and sodium, while rich in beneficial phytochemicals, minerals and essential vitamins.
“Mushrooms contain vitamins and minerals including B vitamins, potassium, selenium, copper and zinc in varied quantities,” says Humphries. “Perhaps my favourite aspect is the presence of the hard-to-find mineral selenium. This useful nutrient is available from dried porcini mushrooms, and many wild edible mushroom species.”
One particularly uncommon quality of mushrooms is that when exposed to sunlight or UV light during their growth phase, they can produce vitamin D. However, Humphries notes that while this can be beneficial, it’s hard for consumers to know exactly how much vitamin D is present in a particular box of mushrooms, as it can vary from batch to batch.
Mushrooms have cell walls which are rich in various forms of a type of fibre called beta-glucan. The shiitake mushroom, for example, contains a beta-glucan called lentinan which has attracted considerable attention over the years for its immune-boosting properties. One of the reasons for this is because when these beta-glucans are broken down by microbes in the gut, they increase the production of a range of useful metabolites called short-chain fatty acids which can help regulate the immune system in various positive ways.
“The beta-glucans in mushrooms appear to have prebiotic effects, supporting the growth of friendly [gut] bacteria,” says Dr Daniel Commane, an associate professor at Northumbria University, who has previously conducted research on mushrooms.
Commane also points out that some of the beta-glucans present in mushrooms are very similar to sugar molecules called glucans, which are present within the many diverse fungi which are permanent residents of our gut.
Research shows that our gut fungi communicate on a constant basis with the immune system, an ongoing chatter which is facilitated by glucans. This communication is critical to maintaining immune balance, and if it breaks down, we’re at a greater risk of inflammatory diseases.
As a result, Commane says that one of the theories for why eating mushrooms could be good for your immune system, is because the various beta-glucans they contain help support this “cross-talk” between gut fungi and immune cells.
“This is very much an ongoing area of study, with evidence emerging to suggest that consuming glucans [through mushrooms] may help protect against things like cold and flu,” he says.
This is a little more speculative, but last year, a paper from the University of Reading’s nutritional sciences department highlighted some studies showing that consuming various mushrooms could hold benefits for cognitive health.
According to Ellen Smith, a researcher at Northumbria University, the strongest evidence for any health benefits is related to lion’s mane mushrooms. This is based on work on animals and in test tubes, but also a handful of small trials which have identified a reduction in anxiety and depression in some people, as well as improvements in cognitive decline in older adults.
It’s thought that mushrooms feed beneficial gut bacteria, which in turn has a positive impact on the brain. Different species of mushrooms also contain various bioactive chemicals. Widely available white button mushrooms, for example, contain bioactives called ergosterols, oyster mushrooms contain ergothioneine and lion’s mane mushrooms contain hericenones and erinacines. Each of these chemicals may be capable of exerting their own protective effects on the brain, either directly or indirectly, based on the findings of test tube studies.
“When we look at the existing limited research, there are numerous different mechanisms that might mean lion’s mane can enhance nerve growth factor [which facilitates the growth of nerve cells in the brain], exert an anti-inflammatory effect [in the brain], and modulate gut microbial composition,” says Smith. “In younger adults, emerging evidence tentatively suggests some improvements in cognitive task performances, such as quicker reaction times and some changes to mood scores. However, the evidence is still limited when it comes to determining the efficacy of lion’s mane.”
At present, it’s only possible to buy certain mushroom species like lion’s mane, from specialist growers such as Merit Mushrooms. So should you opt for one of the many widely available supplements instead?
“Medicinal mushrooms like turkey tail, lion’s mane, reishi, cordyceps and chaga have received research interest thanks to their potential health benefits,” says Eva Humphries. “With the exception of online orders for lion’s mane, these mushrooms are not readily available in supermarkets, so supplemental forms are the only option.”
While there is a whole universe of mushroom powders, coffees and gummies, flourishing on TikTok and other social media outlets, Humphries says it is important to bear in mind that there are currently no permissible health claims relating to medicinal mushroom supplements under EU regulations, because of lack of evidence. And if you’re buying supplements, it’s best to opt for a company which specifically says that they batch-test for heavy metals and toxins.
“Mushrooms naturally accumulate heavy metals such as arsenic and cadmium which are associated with negative health consequences,” says Humphries. “At present, there are no requirements to batch-test mushroom powders for heavy metals, but luckily some supplement companies do this voluntarily.”
The best ways to eat mushrooms, according to nutritionist Eva Humphries
Eva says: “Dried porcini can add a delicious savoury flavour, providing depth to these dishes. Start by soaking the dried porcini mushrooms in hot water for 20 minutes to basically make a ‘tea.’ Then drain and reserve the soaking liquid to add delicious umami flavours to your dish, either as a replacement or in addition to stock.”
Eva says: “Portobello mushrooms are barbecue heroes thanks to their meaty texture and capacity to hold cheese in their upturned caps.”
Eva says: “Seasonal varieties of fresh mushrooms such as chanterelles, morels and hen of the woods mushrooms are best cooked simply and savoured for their full flavour profile. I have a slight obsession with chanterelle mushrooms cooked in butter, sprinkled with a little bit of fresh parsley and piled on top of warm sourdough toast.”
Incorporate woodland or exotic mushroom mixes into noodle broths or stews
Eva says: “These mixes found in supermarkets are branded ‘exotic’ but most are grown in the UK either by the Livesey Brothers or Smithy Mushrooms. They contain a combination of meaty shiitake mushrooms that are incredible in noodle broths, to add more flavour to stews, or to lift a plant-based lentil ragù.”
Eva says: “Oyster mushrooms are rather porous meaning they hold flavour well. Marinating them in a mix of spices, oil and soy sauce quickly transforms them into a delicious filling for sandwiches or pita bread.”
The six most common mushrooms, their health benefits, and where to find them
1. White button mushrooms
Found in pretty much every supermarket, these mushroom staples are a great source of B vitamins and minerals.
2. Chestnut mushrooms
Also known as cremini or baby bella mushrooms, these are a widely available, light to dark brown version of the white button mushroom. Richer and nuttier in flavour, they’re packed with more vitamin B2 than most garden vegetables, and also contain antifungal and anti-inflammatory chemicals.
3. Portobello mushrooms
Less spongy and meatier in texture, you can get these flat, open-capped mushrooms from Sainsbury’s, M&S and Waitrose. They contain polysaccharides which act as useful prebiotics for the gut.
4. Shiitake mushrooms
Another supermarket staple, either in whole form or pre-dried and sliced, these mushrooms have been associated with boosting immune function and lowering cholesterol levels.
5. Oyster mushrooms
These are more limited to M&S or specialist suppliers, but they’re a popular meat substitute, rich in beneficial plant chemicals which can protect the body’s cells.
6. Porcini mushrooms
You’ll typically find them pre-packaged and dried in many supermarkets. Eating porcini mushrooms can aid digestion and even promote heart health.
Ozone, described as 'cold', is a key component of 'outside smell'.