Differences between edible and medicinal mushrooms

Mushrooms have accompanied humanity for millennia, both at the table and in the apothecary. However, the distinction between edible and medicinal mushrooms is not always evident, especially when some species transition between both categories. Worldwide, it is estimated that we know of more than 2,100 species of culinary wild mushrooms and approximately 470 species with medicinal use.

A distinction based on intended use

The first fundamental difference between edible and medicinal mushrooms does not lie so much in the species itself, but in the intention with which they are used. Edible mushrooms are harvested or cultivated primarily for their nutritional and gastronomic value, while medicinal mushrooms are used specifically for their demonstrated therapeutic properties. This differentiation, however, presents gray areas: species such as shiitake (Lentinula edodes) are appreciated both for their exquisite flavor and their effects on the immune system, and lion's mane (Hericium erinaceus) stands out not only as a culinary delicacy but also for its benefits to the cognitive and digestive systems.

Nutritional composition of mushrooms

Edible mushrooms constitute an exceptional food source. Their protein content can reach between 10% and 40% of their dry weight, far exceeding most vegetables, and they contain all the essential amino acids for the human diet. Additionally, they are rich in fiber, low in fats, and completely cholesterol-free. Their vitamin profile includes B group vitamins, C and D, being one of the few non-animal sources of vitamin D2. In this context, edible mushrooms are consumed primarily for these basic nutritional contributions.

Medicinal mushrooms, on the other hand, while maintaining a similar nutritional profile, are distinguished by presenting significantly higher concentrations of specific bioactive compounds. These compounds, such as triterpenes, high molecular weight β-glucans, heteropolysaccharides, pectins, and hemicelluloses, can constitute from 10% to 50% of their dry weight. The essential difference lies in the fact that these bioactive compounds are found in therapeutically relevant quantities in medicinal mushrooms.

The importance of β-glucans

β-glucans represent one of the most studied compounds in medicinal mycology. They are polysaccharides formed by glucose chains linked through beta-glucosidic bonds. However, not all β-glucans are equivalent. The β-glucans of medicinal mushrooms possess a specific structure: β-(1,3) bonds in their main chain with β-(1,6) branches, a characteristic that is crucial for their activity on the immune system.

This structure differs notably from the β-glucans present in cereals such as oats or barley, which present β-(1,3)/(1,4) bonds and lack the same immunomodulatory activity. Fungal β-glucans are recognized by specific receptors of innate immune cells, such as macrophages, neutrophils, and NK (natural killer) cells. By binding to receptors such as Dectin-1, TLR2/4/6/9, and the complement receptor CD11b, they activate signaling pathways such as MAPK-NFκB and Syk-PKC, which triggers a more effective immune response against pathogens.

The mechanism of action of β-glucans is particularly elegant: after their intestinal absorption, mainly in the Peyer's patches of the small intestine, they are phagocytosed by macrophages that circulate through the body to various lymphoid tissues. There, these macrophages fragment the β-glucans, and some of these fragments are captured by neutrophils, causing their "priming." This process means that neutrophils are prepared to recognize and respond quickly to threats such as viruses and bacteria.

Terpenoids and phenolic compounds – Beyond β-glucans...

Beyond β-glucans, relevant for their role in immune modulation, medicinal mushrooms are distinguished by a complex and specific matrix of bioactive compounds, whose composition and function vary notably between species. In the mushrooms we cultivate and process at Boscum (Hericium erinaceus, Ganoderma lingzhi or lucidum, Inonotus obliquus, Lentinula edodes and Grifola frondosa), this diversity includes terpenoids (especially triterpenes), phenolic compounds, fungal sterols, glycoproteins and other specialized metabolites that explain most of their differential physiological effects, which is why their quantification and standardization is key to evaluating the real efficacy of a quality medicinal extract.

In Reishi (Ganoderma lingzhi or lucidum), ganoderic acid and lucidenic acid type triterpenes are key to its adaptogenic profile: these compounds are associated with anti-inflammatory, immunomodulatory effects and regulators of the stress-immunity axis, complementing the structural action of polysaccharides. In Chaga (Inonotus obliquus), both triterpenes such as inotodiol and its high concentration of polyphenols and melanins stand out, responsible for potent antioxidant activity and its interest in contexts of cellular protection against chronic oxidative stress.

Lion's Mane (Hericium erinaceus) presents a different profile: in addition to immunoactive polysaccharides, it contains specific phenolic compounds and terpenoids (such as hericenones and erinacines) that have been studied for their ability to stimulate neurotrophic factors and support nervous system health, which clearly differentiates it from mushrooms with a predominantly immune focus.

In Shiitake (Lentinula edodes) and Maitake (Grifola frondosa), along with well-characterized β-glucan fractions, fungal sterols, phenolic compounds and glycoproteins contribute to hypolipidemic, immunomodulatory and antioxidant effects, reinforcing the importance of considering the extract as a bioactive whole and not as a sum of isolated compounds.

Representative examples: from plate to pharmacy

Reishi, known as the "mushroom of immortality" in traditional Chinese medicine, perfectly exemplifies the concept of medicinal mushroom. Rich in triterpenoids, polysaccharides, nucleotides, steroids and alkaloids, its traditional use encompasses the treatment of high cholesterol, hypertension, chronic fatigue, stress, anxiety, diabetes and insomnia. Its polysaccharides are capable of increasing survival in animal models with carcinoma, acting as an adjuvant to chemotherapy treatment.

Lentinan, a β-glucan isolated from shiitake, represents one of the most exhaustively studied compounds. Its specific molecular structure consists of five glucose units linked in β-(1,3) bonds with two glucose branches in β-(1,6). In Japan, lentinan has been approved for more than 20 years for intravenous use as a complement to chemotherapy. This compound has demonstrated significant immunomodulatory effects by activating the secretion of cytokines such as interferon gamma.

Cordyceps (Ophiocordyceps sinensis) deserves special mention for containing cordycepin, an adenosine analog that interferes with DNA synthesis, limiting the growth of microorganisms and exerting anti-inflammatory and antitumor effects.

The importance of concentration and extracts

A crucial difference between the food and medicinal use of mushrooms lies in the concentration of bioactive compounds and the form of administration. To obtain significant therapeutic effects from a mushroom like shiitake, it would be necessary to consume quantities far greater than those usual in cooking. For this reason, medicinal mushrooms are usually administered in the form of concentrated extracts or food supplements, where extraction techniques allow the concentration of active compounds at therapeutically relevant levels.

Differences between powder and medicinal mushroom extracts

Medicinal mushroom powders have low bioavailability due to chitin that traps the active compounds. Simple extracts (aqueous or alcoholic) capture only part of the bioactive compounds. Dual hydroalcoholic extraction combines both methods, releasing both beta-glucans and triterpenes. The concentration ratio and laboratory analyses certify the quality of the final extract.

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Medicinal mushroom extracts use specific methods such as hot water extraction or alkaline solutions to isolate polysaccharides with greater biological activity. Analysis of specialized cultivated species shows β-glucan contents close to 50% of dry weight, levels impossible to achieve through conventional food consumption.

A continuous spectrum rather than a dichotomy

The distinction between edible and medicinal mushrooms does not represent a sharp division, but rather a continuous spectrum. All edible mushrooms contain bioactive compounds to some extent, and many medicinal mushrooms are perfectly edible and tasty. The fundamental difference lies in the concentration of bioactive compounds, the intended use and the form of preparation. A common mushroom provides excellent nutrition; a concentrated reishi extract offers therapy. Between both extremes exists a wide range of species that nourish while healing, reminding us that the separation between food and medicine has always been more cultural than biological.

Contemporary research continues to reveal the potential of these extraordinary organisms. While edible mushrooms will continue to enrich our tables with proteins, vitamins and minerals, medicinal mushrooms are consolidating as a promising source of bioactive molecules with therapeutic applications supported by growing scientific evidence. Understanding their differences allows us to better take advantage of both their nutritional benefits and their healing properties.

References

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13. Cover image: Kew Garden - State of the World's Plants and Fungi 2023