The Nutritional Power of Mushrooms

nutrition power of mushrooms - thrive magazine

Mushrooms are certainly having their time in the limelight just now, with medicinal mushroom based products coming to market. Nutritionist and Thrive Expert Anne Lecomber looks at the power of mushrooms.

Mushrooms are one of the most versatile ingredients you can have in your kitchen. With about 2000 edible species of mushrooms, it may surprise you that just 35 of these are grown commercially, and a mere 20 are cultivated on an industrial scale. You would think that the combination of variety and versatility is enough to have the whole world loving mushrooms, but people tend to love them or hate them.

The Western world has largely overlooked Mushrooms until recently and is mycophobic in comparison to the Eastern world which has a long history of using them in traditional medicine. It isn’t that we don’t have mushrooms in Europe and the Americas. On the contrary, the UK alone has a wide variety of edible mushrooms that grow in various locations and seasons. Mushrooms weren’t cultivated in Europe and America until the 17th and 19th century respectively. Historically, Western culture has associated fungi with mysticism, magic and rituals. It wasn’t until the 1950s that scientists began to investigate these poorly understood fungi.

Mushrooms were once believed to be low in calories and nutrients, but we now know that they are highly nutritious, rich in vitamins and minerals, antioxidants, with a moderate fibre content depending on the species. They are the only vegan dietary source of vitamin D without fortification. People buying mushrooms as a vitamin D source need to be aware of how they have been grown as mushrooms require sunlight to convert the vitamin D precursor Ergosterol to vitamin D2. Most European mushrooms grown for retail outlets are grown in atmospherically controlled dark rooms.

Wild mushrooms sampled in the summer and early autumn can contain up to 30 times more vitamin D than their retail counterparts!

Wild mushrooms sampled in the summer and early autumn can contain up to 30 times more vitamin D than their retail counterparts which typically have less than 1 μg vitamin D per 100g. Bearing in mind 1 portion of mushrooms is about 100g, it wouldn’t be wise to rely on these types of mushrooms to get the UK daily vitamin D recommendation of 10 μg per day. Wild mushrooms, or alternatively and more conveniently, mushrooms that have been treated with UV light will have higher levels.

What is a medicinal mushroom?
It is any mushroom that contains bioactive compounds that have therapeutic uses for either use in functional foods or for pharmacological drugs. The most commonly consumed mushrooms are the button, oyster and shiitake mushrooms, and the fabulous umami tasting shiitake mushrooms happen to be medicinal. So, if you aren’t familiar with medicinal mushrooms, you could already be consuming them.

Of all the compounds shown to have therapeutic effects, polysaccharides polysaccharopeptide (PSP) and polysaccharopeptide Krestin (PSK) from the Turkey Tail mushroom are the best known commercially. They are more simply known under the group category of β-glucans. β-glucans are thought to stimulate the immune system.
PSP and PSK are potential prebiotics because of their non-digestible property. The extracted powder form could be more prone to digesting enzymes, therefore eating the whole of the mushroom is thought to be most beneficial.

Not all β-glucans are equal…
There are recommendations to increase beta-glucan intake to help reduce blood cholesterol, but these recommendations are based on those found in oats and are structurally different to the β-glucans found in mushrooms.

Top tip!

When choosing your functional food product, don’t be seduced by large polysaccharide numbers. This is meaningless. Look for the beta-glucan numbers!

Other mushrooms with potential therapeutic properties are:
• Reishi Mushroom (Ganoderma lucidum)
• Chaga Mushroom (Inonotus obliquus)
• Lion’s Mane (Hericium erinaceus)

Claims range from helping with depression and other mood disorders, and cognitive function, to combatting oxidative stress and the aging process. Most of these studies have been performed in the laboratory or in animals, and we don’t have any strong evidence to back these claims up.

Although fungi research is in its infancy, I’m excited to find out more about this underrated ingredient, especially with so many trials in the pipeline. We have barely scratched the surface. Even without the medicinal properties, they are a nutritious addition to nearly any meal, and they make a great meat substitute because of their texture and earthly taste. I hope I’ve convinced you to try as many different types of mushrooms as you can.

To remember… If you are interested in learning to forage your own wild mushrooms, please seek expert advice as you need to be able to identify them correctly as some are poisonous.

Thanks to Thrive Expert Anne Lecomber for this article as feature inside Thrive Magazine Winter 2019.
Rerfs:Vetvicka, V.; Vannucci, L.; Sima, P.; Richter, J. Beta Glucan: Supplement or Drug? From Laboratory to Clinical Trials. Molecules 2019, 24, 1251