Mushrooms: Natural Parasite Killers?

Mushrooms are a type of fungus that have been used as a food source and for medicinal purposes for centuries. Some mushrooms are carnivorous and have evolved various capabilities to capture and kill their prey, including parasites. Oyster mushrooms, for example, are known to kill and devour nematodes, a type of roundworm, by using toxins to paralyze them. In addition to their carnivorous capabilities, mushrooms have been found to exhibit antimicrobial and anti-parasitic properties, making them a potential source of therapeutic agents and medicine. Medicinal mushrooms, such as Ganoderma sp., have been studied for their potential to treat various chronic diseases, including cancer, diabetes, hypertension, and hepatitis. The compound Beta-glucan, found in mushrooms, is believed to be effective in inhibiting the adhesion of intestinal parasites, bacteria, and viruses.

Oyster mushrooms kill and eat roundworms

Oyster mushrooms are a delicious fungus that features in cuisines worldwide. However, they are deadly to roundworms. Also known as nematodes, these microscopic worms are one of the most abundant life forms on Earth. Nematodes are little animals with guts, nerves, muscles, and their own primitive form of hopes and dreams.

Oyster mushrooms are carnivorous and have been found to produce a toxin that kills and paralyzes roundworms. This toxin, called 3-octanone, is a nerve gas that is encapsulated in microscopic, lollipop-shaped structures on the mushroom's surface. When a nematode touches these structures, the gas is released, disrupting the worm's cell membranes and causing paralysis and death. The oyster mushroom then digests the worm through its mycelium, a thread-like feeding network.

This mechanism of killing and eating roundworms is unique to oyster mushrooms and differs from those used by other carnivorous fungi. Scientists had known for decades that oyster mushrooms feasted on roundworms, but they had not understood how their toxins worked. Now, researchers have finally figured out the oyster mushroom's deadly secret.

The discovery of how oyster mushrooms kill and eat roundworms could have important implications. For example, it may mean that oyster mushrooms can no longer be considered a truly vegan food. Additionally, understanding how the toxin works could help scientists develop new pesticides or anti-parasitic drugs.

Mushrooms produce compounds that are active against parasites

Mushrooms have been used medicinally for thousands of years. Ötzi the Iceman, preserved in the Italian Alps for approximately 5,300 years, was discovered with whipworm eggs in his digestive tract and a leather strap around his neck threaded with mushrooms known to kill intestinal parasites. Ancient Chinese medical texts also describe reishi as a tonic against ageing.

Today, mushrooms are still used to combat parasites. For example, coccidiosis is caused by parasites of the genus Eimeria that infect the intestinal tract of birds and is transmitted through infected faeces. Lectins, which are carbohydrate-binding proteins found in mushrooms, stimulate disease-fighting cells by binding to their sugar residues, inducing the release of potent immune-system proteins called cytokines. In a study, scientists injected lectin extracted from Fomitella fraxinea, a wood-rotting mushroom, into 18-day-old chicken embryos to activate their innate immune systems. The treatment significantly protected the chickens against coccidiosis-associated weight loss and reduced faecal shedding of live parasites.

Oyster mushrooms are another example of mushrooms that produce compounds that are active against parasites. Oyster mushrooms are carnivorous and have a particular appetite for microscopic nematodes, a type of worm. The mushrooms grow on nutrient-poor rotting wood, and they consume the nitrogen-rich worms to obtain the essential element nitrogen. The mushrooms paralyze and kill the worms with a toxin, devouring their flesh with root-like tendrils called hyphae. The toxin was found to be 3-octanone, a nerve gas encapsulated in microscopic, lollipop-shaped structures on the mushroom surface.

Medicinal mushrooms such as Ganoderma sp. are also considered to be a key source of therapeutic agents. Literature reviews suggest that Ganoderma sp. components exhibit a variety of bioactivities, including anti-tumour, immune-modulatory, antioxidant, antihypertensive, and anti-androgenic properties. To date, most of the reviews on Ganoderma sp. have focused on its anticancer, antioxidant, and immune modulation activities. However, the anti-parasitic activities of Ganoderma sp. have also been explored, with limited compounds tested and known to be active against several parasites.

Mushrooms can be used to treat coccidiosis in chickens

Coccidiosis is a parasitic disease that affects the intestinal tract of chickens, causing decreased animal production and increased mortality. The disease is caused by parasites of the genus Eimeria and Isospora, which belong to the phylum Apicomplexa. It has a complex life cycle and is of great economic significance in farming, especially in chicken farms.

Medicinal mushrooms, specifically the Ganoderma sp. variety, have been found to exhibit anti-parasitic properties. Literature reviews suggest that Ganoderma sp. components exhibit a variety of bioactivities, including anti-tumour, immune-modulatory, antioxidant, antihypertensive, and anti-androgenic properties. In addition, Ganoderma sp. is widely used for the remedy of various chronic diseases such as cancers, diabetes, hypertension, and hepatitis.

Mushrooms and their extracts have gained interest in medicine and as dietary supplements due to their immune-enhancing and antitumor properties. Studies have shown that mushroom and herb polysaccharides can have positive effects on the immune responses of chickens infected with Eimeria tenella, a parasite that causes coccidiosis. In one study, chickens infected with Eimeria tenella were fed mushroom and herb polysaccharide extracts, and their immune responses were compared to a group that was immunized with a vaccine. The results showed that the extracts had a positive effect on the chickens' cellular and humoural immunity, and the groups fed with the extracts had lower cecal oocyst output and lesion scores than the group immunized with the vaccine only.

However, it is important to note that mushrooms should be used cautiously as they may harbour toxic levels of metals (such as arsenic, lead, cadmium, and mercury) and radioactive contamination.

Mushrooms have been used medicinally for thousands of years

The use of mushrooms as medicine is deeply rooted in cultural history. For example, the alchemist Tao Hongjing, from the 5th century, described several medicinal mushrooms, including ling zhi (Ganoderma lucidum) and zhu ling (Dendropolyporus umbellatus), some of which were reportedly used by Shennong many centuries earlier. In traditional Chinese medicine, Phellinus spp. (also known as "Sanghuang" in Chinese) have been extensively studied for their health-promoting effects. According to Chang (2001), medicinal mushrooms have been used as a dietary supplement or medicinal food in China for over 2000 years.

Mushrooms are nature's miniature pharmaceutical factories, rich in a vast array of novel constituents. They are a valuable source of bioactive compounds and are extensively used as functional foods. The medicinal properties of mushrooms have been confirmed through intensive research conducted worldwide. Literature reviews suggest that Ganoderma sp. components exhibit a variety of bioactivities, including anti-tumour, immune-modulatory, antioxidant, antihypertensive, and anti-androgenic properties. They are widely used for the remedy of various chronic diseases such as cancers, diabetes, hypertension, and hepatitis.

However, it is important to critically evaluate claims about the miraculous properties of medicinal mushrooms. While they have been used for thousands of years, there is limited scientific evidence supporting the use of mushroom extracts in the treatment of diseases. Major investments in objective clinical trials are needed to develop this natural pharmacopeia further.

Mushrooms are a source of vitamin D

Mushrooms are a good source of vitamin D. Vitamin D is an essential nutrient for people of all ages, and food sources of vitamin D or supplements are considered the safest way to meet vitamin D needs. Mushrooms are the only significant source of vitamin D in the produce department, as no other fruits and vegetables contain enough of the nutrient to be considered beneficial.

The two main dietary forms of vitamin D are D2, found in fungi and yeast, and D3, found in animals. The most common form of vitamin D in mushrooms is D2, with lesser amounts of vitamins D3 and D4. Vitamin D3 is the most common form in animal foods. Sun-dried and UV radiation-exposed mushrooms are a potentially important source of dietary vitamin D (as vitamin D2). Vitamin D-enhanced mushrooms are the only non-animal food product with substantial amounts of bioavailable vitamin D and are, therefore, a primary source of dietary vitamin D for vegans and vegetarians.

When commonly consumed mushroom species are exposed to a source of ultraviolet (UV) radiation, such as sunlight or a UV lamp, they can generate nutritionally relevant amounts of vitamin D. The concentration of vitamin D2 generated depends on the type and orientation of the mushrooms, whether they are sliced or whole, the distance from the lamp housing, the size of the mushroom, and the total number of pulses received. For example, in button mushrooms, three pulses (1 second) of UV radiation generated 11.9 μg D2/g DM, and nine pulses (3 seconds) generated 20 μg D2/g DM. The maximum concentration of vitamin D2 (27 μg/g DM) was reached after 12 pulses (4 seconds).

Although the levels of vitamin D2 in UV-exposed mushrooms may decrease with storage and cooking, if they are consumed before the ‘best-before’ date, the vitamin D2 level is likely to remain above 10 μg/100 g fresh weight. This is higher than the level in most vitamin D-containing foods and similar to the daily requirement of vitamin D recommended internationally. Some wild mushrooms are excellent sources of vitamin D2 due to their exposure to UV light. Morels are a type of wild mushroom. However, many commercially grown mushrooms are grown in the dark and contain very little D2.

Frequently asked questions