Oysters are large, flat shellfish. People can eat some types of these sea creatures, either cooked or uncooked, with many considering them a delicacy.

Oysters refer to several edible, marine, bivalve mollusks that belong to the Ostreidae family. Two common types include Pacific and Eastern oysters. They play a vital role in the ecosystem — they improve water quality by filtering pollutants out of the water and help provide suitable habitats for fish, invertebrates, and other shellfish.

Oysters have an irregularly shaped shell that contains the inner body, which is also known as the meat. While many people are aware of the reported aphrodisiac properties of oysters, they are also highly nutritious and can provide some health benefits.

This article discusses the nutritional benefits of oysters, their health benefits, and any potential risks and concerns about eating them.

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According to the Department of Agriculture, 100 grams (g) of raw Pacific oysters contain:

Oysters are nutritious and contain many vitamins and minerals that can provide health benefits. Some examples include:

  • Protein: Oysters are a high source of protein and are relatively low in calories, meaning they can help people feel fuller. Research suggests that higher-protein diets can help reduce obesity. Protein is present in every cell, while a sufficient intake is vital for keeping muscles, bones, and tissues healthy.
  • Zinc: Supports several functions in the body, such as immunity, wound healing, and growth and development. The substance also plays a role in sexual function, which may be why many individuals consider oysters an aphrodisiac.
  • Vitamin B12: A B vitamin that is important for nerve tissue health, brain function, and the production of red blood cells. When levels of this vitamin are low, people may experience nerve damage and fatigue.
  • Omega-3 fatty acids: Evidence suggests these fatty acids may play a role in heart health, brain function, and growth and development. They also possess anti-inflammatory properties and may help reduce the risk of heart conditions.
  • Iron: This mineral is vital for the proper functioning of hemoglobin in the blood. It is also important for growth, neurological development, and the production of some hormones. Further research suggests low iron levels may contribute towards sexual dissatisfaction, again indicating a possible sexual benefit.
  • Magnesium: This mineral has many functions in the body, including muscle and nerve function, regulating blood pressure, and supporting the immune system.
  • Potassium: An essential macromineral that supports key processes in the body, such as the function of the kidneys, heart, muscles, and nervous system.
  • Selenium: An essential trace mineral that plays a key role in thyroid function and metabolism. It also contains antioxidant properties, which may help protect against cancer, heart disease, and cognitive decline.

While oysters can provide many health benefits, they may also pose some potential concerns, such as:

  • Shellfish allergy: While it is more common to be allergic to crustaceans than mollusks, people can still experience allergic reactions after eating oysters. The symptoms can vary among individuals and may include vomiting, stomach pain, and shortness of breath.
  • Contaminants: Oysters, particularly if raw, can contain contaminants such as harmful bacteria. For example, they may contain Vibrio bacteria, which may cause diarrhea, vomiting, and in some cases, severe illness. Cooking them with proper techniques can kill harmful bacteria.
  • Mineral toxicity: Oysters are rich in many important minerals. While toxicity is more likely with supplements, eating too many oysters may also cause similar negative health effects if individuals consume too much zinc and selenium, according to an older study.

People can cook oysters in a variety of ways, such as steaming, boiling, frying, broiling, and baking. When ordering at a restaurant or cooking at home, it is important to ensure a person cooks them fully before consumption.

While some individuals may enjoy eating raw oysters, it can be dangerous. Eating raw or undercooked oysters can put people at risk of foodborne illness. Oysters containing bacteria typically do not look, smell, or taste different from other harmless oysters. Therefore, properly cooking them is the only way to kill the harmful bacteria.

The Centers for Disease Control and Prevention (CDC) provide the following instructions for safely cooking oysters:

  • Before cooking, discard any shellfish with open shells.
  • Boil the oysters until the shells open.
  • Either continue boiling the oysters for another 3–5 minutes or add to a hot steamer and cook for another 4–9 minutes.
  • Only eat oysters that open during cooking and throw out any that do not fully open after cooking.

Alternatively, for shucked oysters, people can also consider the following cooking methods:

  • fry oysters in oil for at least 3 minutes at 375°F (190.5°C)
  • broil 3 inches from heat for 3 minutes
  • bake at 450°F (232.2°C) for 10 minutes

People can include oysters in their diet in a variety of ways. Some options may include:

  • leek, celeriac, and oyster broth
  • oysters Rockefeller
  • oysters with pancetta
  • oysters poached in red wine sauce
  • grilled oysters with parmesan cheese
  • oyster risotto
  • oysters in beer batter
  • champagne gratin of oysters
  • oysters with spinach
  • chili-coated oysters with red onion salsa

Oysters are bivalve mollusks that are highly nutritious and may provide some health benefits. They are a good source of protein, contain omega-3 fatty acids, and are rich in minerals such as zinc, selenium, and iron.

However, raw or undercooked oysters can contain harmful bacteria that can make people seriously ill. Therefore, health experts recommending cooking oysters fully before consuming them.