Oysters are bivalves living in estuaries where the fresh water of rivers meets the salt water of the ocean. As filter feeders, oysters attach themselves to smooth hard surfaces and filter nutrients from the water they take in. Some oyster middens, or shell piles, in North America are thousands of years old, and these mollusks have been an important part of the human diet throughout history. Oysters can be prepared in many ways, raw or cooked, to make high-protein, high-nutrition seafood dishes.
Quality Protein Source
Oysters are an excellent source of protein and a number of other nutrients. They are low-calorie, almost fat-free, high in vitamins and minerals and, according to the University of Washington, much easier to digest than meat. A hundred grams of oyster has 8.4 grams of protein but only 66 calories and 1.8 grams of fat, while 100 grams of cooked steak piles on more than 400 calories and nearly 35 grams of fat with its 22.2 grams of protein.
Other Nutrients
Oysters supply the macronutrients and many of the micronutrients essential to a healthy diet. In addition to their high protein content, oysters provide carbohydrates and a bit of unsaturated fat. Three and a half ounces of raw oysters have all the required daily vitamin B-12 and zinc, 65 percent of daily niacin and 35 percent of daily iron. Eating oysters is a good way to get copper, manganese, calcium, potassium, phosphorus, vitamin A and iodine.
Safe Protein
People with immune system disorders and diseases that affect the liver, blood or stomach should not eat raw oysters. Check with your health care provider to determine your level of risk from raw seafood. There are bacteria native to the coastal waters where oyster beds form that can adversely affect some people. These bacteria, Vibrio vulnificus, can be killed by cooking the oysters. The Mississippi Department of Marine Resources says to cook oysters to a temperature of 140 F for four to six minutes to kill pathogens. The protein in the oysters will survive and so will you. However, cooking will not do anything to alter marine pollutants that may have been ingested by an oyster, so always buy raw oysters from a reliable source.
Oyster Protein Adhesive
Oyster protein has potential value that goes beyond nutrition. Oysters glue themselves to a surface and remain fixed there for life. The glue holds them against currents and predators and is a powerful adhesive. Researchers from Purdue University studied the glue oysters produce to determine its composition, and discovered that it contains five times the protein of an oyster's shell. The glue is 90 percent calcium carbonate, but this chalky substance would not create a cement-like bond. The rest of the glue is protein, and the mix of the protein and the chalk seems to create the tough bond. These findings may be helpful in the quest to find a post-surgical glue that would eliminate the need for staples or sutures. Understanding the oyster protein glue might also lead to the development of an environmentally safe way to protect boat hulls from encrustations of barnacles and mussels.
References
- Purdue University News Service; Purdue Researcher Cracks Open Secret of Oysters' Ability to Stick Together; September 2010
- University of Washington News You Can Use: Purchasing and Preparing Oysters: Nutritious and Delicious
- University of Florida Extension; Florida Food Fare; Oysters; Jean Meadows, et al.
- Auburn University Marine Extension and Research Center; Aquacultured Oysters; Brian Perkins; August 1997
- Mississippi Department of Marine Resources; Gone Oystering; November 2001
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