Oyster

What it is and how it is named

Oyster mushroom is the common name for Pleurotus ostreatus (family Pleurotaceae). GBIF lists it as an accepted species name. [3] A review describes Pleurotus mushrooms as widely cultivated around the world and rich in protein, fiber, amino acids, water-soluble vitamins and minerals. [4] For actual nutrient numbers, see mushroom nutrition. "Oyster mushroom" is also used loosely for related Pleurotus species, including king oyster. A result for one species does not transfer to the other.

Traditional use

Proper evidence not found: we did not read a source that describes traditional medicinal use of oyster mushroom, so we do not describe one. We searched PubMed and the reviews listed below.

What research shows

Human research is small and mostly short. All rows below are about the food itself unless stated.

Two of the trials above compare against a calorie-matched or placebo food, which is the right design, but all are small. The cognition findings are from a single research group and have not, in what we read, been repeated by another. We did not read funding statements for these trials, so we do not report them. No trial we read tested cooked oyster mushroom as a treatment for any disease, and none supports using it to treat one.

Forms and why the form matters

Fresh or cooked oyster mushroom is a food. Powders and extracts are different products. The glucose trial used a dried powder stirred into a meal, and its result should not be applied to a fresh mushroom in a stir-fry or to an extract capsule. Supplement forms are covered in mushroom supplement forms; how a food portion compares is on food portions vs supplement amounts.

Official statements

Proper evidence not found: no regulator statement on oyster mushroom as a health product appeared in the sources we read.

Lab data and chemistry

This section is for readers who want the laboratory side. It describes what has been measured in oyster mushroom, not what it does in the body. For what people trials found, see the research table above.

What the laboratory literature reports in this mushroom

Wikidata, through the LOTUS natural-products project, lists 40 compounds as "found in" Pleurotus ostreatus. [10] A presence entry means "reported in at least one study of this species", not "present in every product". The copy of the data we hold does not name the paper behind each statement, so the table gives the Wikidata entry. The identity codes are Wikidata (Q) and ChEBI numbers taken from that copy. Ergothioneine and pleuran are not in that list of 40, but papers we read measured ergothioneine (table B) and tested a beta-glucan called pleuran.

We checked these entries against the saved Wikidata file, not each paper behind them. The ChEBI numbers come from that file and were not opened on the ChEBI site.

Measured values

USDA FoodData Central, per 100 g raw edible portion. Two oyster records exist, and they disagree on some nutrients. Foundation Foods (FDC 1999627, 2021) is the newer one; SR Legacy (FDC 168580, 2018) is the older dataset. [17] [18]

USDA lists vitamin D separately for UV-exposed mushrooms of other kinds (such as button and portabella). It has no UV-exposed oyster record in our copy, so we cannot show an exposed versus unexposed pair here. The 17-fold gap between the two oyster records is in the data as published; we did not find a source explaining it.

Other measured values from papers.

Two of the beta-glucan figures can be compared. Multiplying 23.9 percent by 8 percent dry matter gives about 1.9 g per 100 g fresh (our own arithmetic), which matches USDA's 1.92 g. The trial powder's 8.1 g in 20 g is far higher, so a different assay or a different product was probably involved; the trial abstract does not say. A 2006 survey of cultivated mushrooms found 0.4 to 2.0 mg of ergothioneine per g dry weight overall; oyster, shiitake, king oyster and maitake did not differ from one another and all had more than white button. [19]

What the numbers do and do not mean

• Methods change the answer. For lovastatin in oyster, the papers we read report "not detected", about 1 mg per kg and about 600 mg per kg. The 2021 paper also found that a cheaper UV light-absorption method gave results hundreds of times higher than LC-MS, because other compounds in the mushroom interfere. [13] Treat all lovastatin figures as unsettled. We found no source showing that eating oyster mushroom lowers cholesterol or acts like a statin medicine.
• A compound in the mushroom is not a health effect. Ergothioneine is a food antioxidant, and oyster is among the richer sources in the papers we read. The older-adult trials above used the whole mushroom, and the mechanisms were not shown. [6] [7]
• Food portion versus supplement. USDA's 14 mg ergothioneine per 100 g is for eating the mushroom. We found no oyster mushroom supplement with a measured value, so we give none.
• "Beta-glucan" depends on the test. A trial powder at about 40 percent, a raw mushroom at 24 percent of dry matter and USDA's 1.92 g per 100 g fresh are different bases, not a contradiction. Pleuran in the children's trials is a purified extract, so those results do not carry over to eating the mushroom. [14] [15] [16] Mycelium-on-grain products (see fruiting body vs mycelium) can also count grain starch in a "polysaccharide" figure; we found no oyster measurement of that.
• Ranges vary by strain, growing material, harvest, drying and extraction. One study found that drying cut lovastatin by about 70 to 84 percent, so a dried product is not the same as a fresh mushroom. [20]

Pleuran and other chemistry-linked trials

Pleuran is a beta-glucan purified from P. ostreatus. One randomised, double-blind trial of 175 children with frequent respiratory infections compared a pleuran and vitamin C syrup with vitamin C alone; 36 percent of the pleuran group had no infections over the treatment period versus 21 percent on placebo. [14] A later trial of 249 children (217 completed) found 15.2 percent fewer respiratory infections over 3 months with a chewable pleuran, vitamin D and zinc product than with vitamin D and zinc alone. [15] A trial in 230 children with partly controlled asthma found asthma control better in children under 12, and fewer infections in those 12 and over. [16] These are promising but limited: most come from one research group, we read only the abstracts, and we did not read funding statements. The products were purified extracts combined with vitamins or minerals. They say nothing about cooked oyster mushroom or powders.

Safety notes from the laboratory literature

• Oyster mushroom, like other mushrooms, takes up metals from its growing material. A 2024 laboratory study that added cadmium or mercury to the growing medium found that the mushroom concentrated them. [21] This is not a measurement of shop products, but it is why growing material and testing matter; see heavy metals and contamination.
• A 2024 study of oyster mycelium found no regulated mycotoxins and reported four peptide toxins that were lower in mycelium than in fruiting bodies, which are already eaten. [22] Cooking is still advised; see cooking edible mushrooms safely.