As winter fast approaches, consumers begin to adorn themselves with warm jackets and rejoice in the cheer of the festive period. However, a powerful sense of dread can often creep into the minds of many during this time as a torrent of coughing and spluttering commuters threaten to ruin their fun. However, there may be a hope for these would-be revellers as many nutraceuticals have shown significant promise in terms of supporting immune health — even during the dreaded flu season.
Currently, there is a huge range of functional ingredients that has been proven to promote immune health, including biotics, botanicals and vitamins. However, there’s one group of nutraceuticals that has been growing in popularity in this area in recent years, and that’s mushrooms.
Although mushrooms have been used for centuries in natural medicine, scientists have recently discovered their potential to support gut health, cognition and concentration. Further research has also highlighted the potential of functional mushrooms to boost immune health — whether that be through dietary intake or via supplements. To find out more about potential of fungal species in the immune health space, Annabel Kartal-Allen spoke to Bill Chioffi, Chief Operating Officer at Nammex.
Ergothioneine, an amino acid found primarily in mushrooms ... triggers the cell’s antioxidant defence system
Why mushrooms?
During the last decade, the nutraceutical market has exploded in popularity, with many companies aiming to be the best in their sector. This means that successful industry players have to stand out with a unique selling point (USP). Bill believes that brands in the immune health niche can do this by incorporating mushrooms into their formulations. “Mushrooms are full of unique nutrients that can contribute to our overall wellness; but, when talking about immune health specifically, a key one will always be vitamin D.”
Vitamin D
Vitamin D has been proven to benefit well-being by directly modulating the immune system, impacting crucial cell types such as T-cells, B-cells, monocytes and dendritic cells.1 It has also been found to diminish the presence of proinflammatory cytokines while encouraging the presence of anti-inflammatory ones. Furthermore, the vitamin is able to influence both innate and adaptive immunity — which are both crucial in maintaining day-to-day health.
Ergothioneine
Another nutrient commonly found in mushrooms that’s garnering more attention is ergothioneine. “This amino acid is similar to the compound some folks in the nutraceutical industry call glutathione L,” Bill says: “Glutathione is involved in various metabolic processes, with liver detoxification being a key one.”
Ergothioneine, an amino acid found primarily in mushrooms, has been proven to be a potent antioxidant while also influencing the immune system by promoting the activity of nuclear factor erythroid 2-related factor 2 (Nrf2), which triggers the cell’s antioxidant defence system.2,3 Additionally, SLC22A4, the gene that encodes the ergothioneine transporter found in humans, is regulated by the inflammatory cytokines interleukin-1 (IL-1) β and TNF-α, suggesting that the nutraceutical is part of the body’s natural cellular immune defence line-up.3 
Beta glucans
“Beta glucans can also be found in different forms in most species within the mushroom family, and a number of studies have highlighted their potential to support immune health,” continues Bill. “They do this by triggering immune cells such as natural killer cells, macrophages and neutrophils through a range of targets, including Dectin-1, TLR-2 and TLR-6 and are referred to in overall activity as “immunomodulatory.”4 Beta glucans have also been implicated in the activation of superoxide dismutase and catalase enzymes, which are additional molecules involved in the immune response.5
Ergosterol
Another active ingredient commonly found in mushrooms is ergosterol, Bill explains: “Ergosterol is naturally synthesised by almost all mushrooms and can be involved in immune regulation through its antioxidant and anti-inflammatory properties.6 However, depending on species and source, the presence of ergosterols in mushrooms may vary, so testing to measure content is important in ingredient sourcing.
Bill also stresses the importance of secondary metabolites such as triterpenoids as they have been shown to have immunomodulatory capabilities in a number of studies. For example, ganoderic acid — a triterpenoid derived from the medicinal mushroom Ganoderma lucidum — has been shown to strengthen immune function through the enhancement of Th1 cytokines while also upregulating the impact of the Natural Killer (NK) cell pathway, a signalling cascade commonly associated with the acquired immune response.7
The best fungi for the job
Although Bill believes that all mushrooms hold significant promise to support immune health, he recommends six species specifically.
- Reishi: full of beta-glucans, triterpenoids and antioxidants, reishi mushrooms have been shown to modulate the activity of T-lymphocytes, specialist white blood cells (WBCs) that are involved in the adaptive immune response.8 However, scientists don’t recommend reishi supplementation for those taking certain medications — such as anticoagulants and immunosuppressants — as they have been potentially linked to liver damage in certain studies.9
- Maitake: another edible mushroom species containing a wide range of nutrients, including antioxidants, beta-glucans, vitamins B and C and potassium, maitake has been implicated as an antiviral while also offering support to immune health by modulating WBC counts.10
- Shiitake: these edible mushrooms contain a selection of nutrients, such as vitamin B5, copper, riboflavins and terpenoids.11 A study has suggested that the daily consumption of shiitake mushrooms led to the increased expression of slgA, a surface glycoprotein present in the human gut that mediates the immune response in this region. Study participants also experienced a decrease in C-reactive protein (CRP), a protein that indicates the presence of inflammation in the body at high concentrations.12
- Turkey tail: these fungi have grown significantly in popularity as an immune-modulating solution owing to their high content of quercetin and baicalein, two flavonoids which have been associated with immune health.13 Quercetin has previously been associated with boosting interferon-Y — a protein involved in immunoprotection — while reducing levels of pro-inflammatory enzymes such as LOX and COX.14
- Lion’s mane: lion’s mane mushrooms are commonly eaten by many across the globe and are also popular in supplements owing to their medicinal properties. They contain a plethora of nutrients, including niacin, beta-glucans, thiamine, ergosterol and ergothioneine. In addition to its cognitive function benefits, Lion’s mane has been shown to enhance both humoral and cell-mediated immunity, as well as macrophage-initiated phagocytosis.15
- Chaga: Although this particular species isn’t technically a mushroom, Bill acknowledges its strong potential to support immune health. “Chaga has been shown to offer support to both the passive and adaptive immune system, so it’s another one with great potential for incorporation into an immune formulation.”
The rise in popularity of alternative delivery formats is apparent
Formulating with mushrooms
There are many mushrooms that are considered to be a dietary delicacy, with varieties such as maitake and shiitake making their way into people’s diets in many countries worldwide. However, some highly nutritious mushrooms — although edible — are far from palatable. Therefore, to successfully incorporate fungal ingredients into functional foods and supplements, formulators have to find ways to incorporate their extracts into products that are both efficacious and appealing.
There are many options that nutraceutical developers can take, Bill elaborates: “Mushrooms that have an unpleasant taste or texture are often incorporated into delivery formats wherein these parameters don’t need to be considered, such as a capsule or a tablet.”
However, the rise in popularity of alternative delivery formats is apparent, as an increasing proportion of the public want tasty and unique supplement experiences. “Many brands are now putting mushrooms into cookies, cake mixes and confectionary items, as well as functional beverages and coffee. I’ve even seen ice creams fortified with mushroom extracts, which have proven to be highly successful,” Bill adds.
When considering how to incorporate a functional mushroom into a supplement or functional food/beverage, the target audience should also be a primary consideration. “You have to think about how the demographic you’re trying to cater for may respond to tastes, textures, formats and branding. It’s also worth considering how you can mask the flavour of less appealing mushroom varieties while ensuring your product contains the appropriate nutrients at the right concentrations to deliver immune-specific health benefits.”
Finally, Bill notes the importance of vigilance in the sourcing process: “It’s very important to make sure you are getting mushrooms from high quality vendors that can consistently supply your business with a product that’s both potent and pure. If you’re creating a mushroom supplement, an effective extraction process is also necessary to ensure your product contains the desirable functional ingredients found in that mushroom,” he concludes.
References
1 https://pmc.ncbi.nlm.nih.gov/articles/PMC3166406/.
2 https://pmc.ncbi.nlm.nih.gov/articles/PMC7653990/.
3 www.cambridge.org/core/journals/british-journal-of-nutrition/article/ergothioneine-an-underrecognised-dietary-micronutrient-required-for-healthy-ageing/92CED7FF201A9FB23BEAFF0D3EAD7316.
4 www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2023.1143682/full.
5 www.nature.com/articles/s41598-023-41557-9.
6 www.sciencedirect.com/science/article/pii/S1756464623002219.
7 https://pmc.ncbi.nlm.nih.gov/articles/PMC8600492/.
8 https://pubmed.ncbi.nlm.nih.gov/18048435/.
9 www.healthline.com/nutrition/reishi-mushroom-benefits#TOC_TITLE_HDR_8.
10 www.healthline.com/health/food-nutrition/maitake-mushroom.
11 www.healthline.com/nutrition/shiitake-mushrooms.
12 https://pubmed.ncbi.nlm.nih.gov/25866155/.
13 https://pmc.ncbi.nlm.nih.gov/articles/PMC6010034/
14 https://pmc.ncbi.nlm.nih.gov/articles/PMC4808895/
15 https://pubmed.ncbi.nlm.nih.gov/28266682/.