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Nutrition Information for Oysters


Updated July 15, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Person eating an oyster from an oyster shell
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Oysters are bivalve (having two shells) mollusks that are related to clams, mussels, and scallops. They're an excellent source of zinc, which your body needs for hundreds of different biochemical processes to occur.

A serving of oysters is also a good source of calcium, potassium, iron, magnesium, and vitamin B-12.

One serving is equal to six medium raw oysters or three ounces of canned oysters:

  • 43 to 58 calories
  • 4.8 to 6.0 grams protein
  • 1.44 to 2.10 grams fat
  • 38 to 50 milligrams calcium
  • 3.87 to 5.7 milligrams iron
  • 15 to 46 milligrams magnesium
  • 131 to 195 milligrams potassium
  • 33 to 77 milligrams zinc
  • 7.35 to 16.3 micrograms vitamin B12

Selecting and Serving Oysters

Choose fresh oysters that have been harvested and processed according to safety guidelines -- look for a tag on containers or sacks of oysters. Throw away any oysters that have broken shells, and tap any open shells with your finger. A live oyster should close its shell when you tap it. If it doesn't close, then throw it away.

Fresh oysters should be refrigerated at 40 degrees Fahrenheit or lower until you serve them or use them in a recipe. When you cook fresh oysters, the shells should open up. Discard any oysters that remain closed.

They may be served raw, usually sitting on one shell, or smoked, baked, or as the featured ingredient in oyster stew. Oysters are harvested from both Pacific and Atlantic waters.

Healthy Recipes and Tips

Raw Oyster Safety

Generally, raw oysters are safe to eat, but just as with the consumption of any raw fish or seafood, there is a possibility for food-borne illness. Raw oysters may be contaminated with Vibrio vulnificus, which is a bacteria related to cholera. Oysters harvested in warm water are more likely to be infected than oysters harvested from colder water.

Eating raw oysters also puts you at risk for contracting hepatitis A.

A healthy person who ingests the bacteria may suffer from abdominal pain, vomiting, and diarrhea. The infection can be serious in a person who has liver disease or is immunocompromised, because the bacteria can get into the bloodstream and cause septicemia, which is fatal about 50 percent of the time.

If you've been told not the consume raw oysters, you must avoid them. The only way to kill the bacteria is through cooking. There are myths that adding lots of hot sauce or drinking alcohol while you eat raw oysters will kill the bacteria, but those rumors are not true.


Centers for Disease Control and Prevention. "Vibrio Vulnificus." Accessed February 13, 2012. http://www.cdc.gov/nczved/divisions/dfbmd/diseases/vibriov/.

United States Department of Agriculture, National Nutrient Database for Standard Reference Release 24. "Nutrient data for 15170, Mollusks, oyster, eastern, canned." Accessed February 13, 2012. http://ndb.nal.usda.gov/ndb/foods/show/4609.

United States Department of Agriculture, National Nutrient Database for Standard Reference Release 24. "Nutrient data for 15167, Mollusks, oyster, eastern, wild, raw." Accessed February 13, 2012. http://ndb.nal.usda.gov/ndb/foods/show/4606.

United States Food and Drug Administration. "Fresh and Frozen Seafood: Selecting and Serving it Safely." Accessed February 13, 2012. http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm077331.htm.

United States Food and Drug Administration. "Letter to Health Professionals Regarding the Risk of Vibrio vulnificus Septicemia Associated with the Consumption of Raw Oysters." Accessed February 13, 2012. http://www.fda.gov/Food/ResourcesForYou/HealthCareProfessionals/ucm122277.htm.

United States Food and Drug Administration. "Raw Oyster Myths." Accessed February 13, 2012. http://www.fda.gov/Food/ResourcesForYou/HealthEducators/ucm085385.htm.

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