Oyster Mushrooms: What Are They?

Oyster mushrooms are one of the most sought-after edible mushrooms worldwide. Not only do they taste delicious, but they have a range of potential health benefits too. These fungi are also aesthetically pleasing, adding to their overall appeal.

Here’s all you need to know about oyster mushrooms, including their nutritional and therapeutic value and how to prepare them.

What Are Oyster Mushrooms?

Oyster mushrooms are becoming increasingly popular, and cultivation has increased rapidly in recent years. More and more people are becoming aware of the benefits of mushrooms in general, and oysters are an excellent choice. They are tasty, attractive, and relatively easy to grow.

Therefore, it is perhaps unsurprising that oyster mushrooms are the third most farmed fungus, after white mushrooms and shiitake. In fact, they account for approximately 14% of all mushroom production worldwide.

There are many different oyster mushroom species, all of which belong to the genus Pleurotus. While there are some significant differences between species, all oyster mushrooms share some standard features.

One of these fungi’s most distinctive traits is their shape. Their smooth caps resemble oyster shells or little fans that grow in clusters on rotting wood. They have decurrent gills, meaning their gills run from their caps into their stipes (stalks). Meanwhile, the stipes themselves are much stubbier than those of many other mushrooms and may be completely absent.

Despite these similarities, oyster mushroom species vary in their color, where they grow, and when they are in season. We have listed some of the most common types below. 

Types of Oyster Mushrooms

There are many different oyster mushroom species, and some are much easier to find than others. The most common oyster mushroom types that consumers are likely to encounter include:

• Gray oyster (P. ostreatus)
• Golden oyster (P. citrinopileatus)
• Pink oyster (P. djamor)
• Phoenix oyster (P. pulmonarius)
• King oyster (P. eryngii)

Gray oyster mushrooms are by far the most common and can be found in most large grocery stores. They also grow prevalently in the wild and are relatively easy to recognize. However, they do have some poisonous look-alikes, so careful identification is essential before consumption.

The other types of oyster mushrooms are more challenging to locate but are steadily becoming more widely available.

Many people now opt to grow these more unusual varieties at home. Oyster mushrooms are reasonably straightforward to cultivate, and they are one of the most popular options for mushroom grow kits.

Oyster Mushrooms Benefits

Oyster mushrooms are best-known as a culinary species. However, they also contain various bioactive compounds that could significantly influence our health.

Like most fungi, oyster mushrooms are rich in complex carbohydrates called beta-glucan polysaccharides, which support immune and digestive health. In fact, they have twice the beta-glucan content of white mushrooms.

They also contain antioxidant phenolic compounds and a cholesterol-lowering chemical called mevinolin (lovastatin), among others.

According to a 2015 review, the potential health benefits of oyster mushrooms include:

• Immunomodulatory
• Antioxidant
• Anti-cancer
• Anti-inflammatory
• Antimicrobial
• Cholesterol-lowering

However, there is more evidence to support some of these claims than others.

Research indicates that oyster mushrooms have beneficial effects on glucose and fat metabolism.

One of the best-studied areas is oyster mushrooms’ influence on cardiometabolic health. A 2020 review included eight clinical trials lasting 7–365 days. The results indicated that oyster mushrooms have beneficial effects on glucose and fat metabolism. Some studies also demonstrated reductions in blood pressure.

The review’s authors suggested that these effects are due to the mushrooms’ beta-glucan and mevinolin content. They also proposed that biologically active peptides (proteins) formed during digestion could inhibit angiotensin-converting enzyme (ACE). ACE is an enzyme involved in blood pressure regulation, and ACE inhibitors are a common treatment for hypertension.

Unfortunately, although these results are promising, the quality of the reviewed evidence was low. Therefore, further research is warranted.

How to Use Oyster Mushrooms

It is possible to prepare oyster mushrooms in the same way as any other edible fungus. However, they have a delicate flavor and tend to cook down to almost nothing. Therefore, many people prefer to combine them with other mushrooms in their dishes.

Some of the most common uses of oyster mushrooms include:

• Pan-frying in butter and serving on toast or as a side dish
• Stir-frying with other mushrooms or vegetables and serving with rice or noodles
• Adding to mushroom sauce or soup
• Chopping into an omelet or savory pancake

Before cooking, wipe the mushrooms with a damp cloth to remove any dirt and cut off the tough stems. Then cut them into large, even-sized chunks before adding to your recipe of choice.

Oyster Mushroom Nutrition

Oyster mushrooms are widely considered a functional food due to their potential health benefits. They also have a great nutritional profile, making them a wonderful addition to any healthy diet.

Like all mushrooms, they are low in calories and fat but packed with protein and dietary fiber. They also contain vitamins A and D, B vitamins, and a range of essential minerals.

Below is a summary of oyster mushrooms’ calories and nutritional content. All values are per 100g of raw mushrooms:

• Calories: 33 kcal
• Carbohydrate (by difference): 6.09g
• Protein: 3.31g
• Fiber: 2.3g
• Fat: 0.41g

Summary on Oyster Mushrooms

Oyster mushrooms make a healthy, tasty, and versatile addition to any meal. There are many different varieties, although gray oyster mushrooms are by far the most common. They are recognizable by their clusters of gray, shell-like caps and can be found in most large stores.

These fungi are low-calorie, low-fat, and packed with nutritional compounds. But oyster mushrooms’ benefits do not end there. Scientists believe that they could help to improve our health and wellbeing by supporting immunity and digestive health, reducing cholesterol, and more.