Oysters: Are They Good for You?

Oysters are a delightful bite of pure ocean flavor, or a slimy salty blob. There are many opinions on this polarizing seafood. Fans praise oysters as chewy, distinctive, and fresh-flavored.

Evidence of shellfish consumption by humans dates as far back as 164,000 years ago. Fast forward to roughly 2,000 years ago, history shows the Romans in England enjoying this salty seafood.

In America, oysters were considered a cheap food mainly enjoyed by the working class in the early 19th century. They reached their peak from 1880 - 1901 when the United States produced 160 million pounds of oyster meat per year.

Oyster production has died down considerably in the past century, due partly to habitat destruction and a drop in demand. Still, they remain a popular seafood enjoyed by connoisseurs globally.

Nutrition Information

Oysters are commonly eaten raw with a few drops of lemon juice squeezed on them. Their nutritional content is largely unaffected by any cooking or preparation methods.

Six medium sized oysters contain roughly:

  • Calories: 50
  • Protein: 6 grams
  • Fat: 1 gram
  • Carbohydrates: 5 grams
  • Fiber: 0 grams

Raw oysters are also an abundant source of several vitamins and minerals. They’re a particularly good source of vitamin B12, which research has indicated plays a big role in keeping your brain healthy. Other micronutrients include:

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Potential Health Benefits of Oysters

Oysters are low-calorie and high in micronutrients, making them a healthy food for many people. Many of the specific health benefits of oysters are tied to their abundant array of micronutrients.

Brain Health

The impressive amount of vitamin B12 makes them a natural choice for keeping your brain healthy. A deficiency in vitamin B12 has been associated with dementia, including Alzheimer’s disease. Vitamin B12 deficiency has also been linked to mental health symptoms including depressed and suicidal thoughts. 

Osteoporosis 

Oysters are a rich source of vitamin D, copper, zinc, and manganese. These micronutrients, in combination with calcium, are thought to be key to slowing or even preventing bone loss in older women due to osteoporosis. Additionally, dietary sources of these minerals are thought to be more effective than supplements.

Preventing Selenium Deficiency

Oysters are a naturally rich source of selenium. Selenium is a mineral that the body needs in very small quantities to function properly. When consumed at too high a level, selenium is toxic, however, a deficiency has been linked to cardiovascular disease, infertility, and cognitive decline.

Potential Health Risks of Oysters

While oysters are a great source of various nutrients, they’re not without risks. One especially serious concern is the risk of food poisoning from oysters.

Food Poisoning

Since oysters are most frequently eaten raw, they are especially susceptible to passing on bacterial contamination. One type of bacteria found in oysters — Vibrio vulnificus — is linked to a serious illness - even fatalities.

Unfortunately, there’s no easy way to tell if the oysters on your plate have been contaminated. Serious symptoms typically appear within 24 to 48 hours after consumption and may include fever, chills, nausea, vomiting, diarrhea, and shock.

Those most at risk for serious complications from bacterial contamination are people with cancer, diabetes, and liver disease. Those with alcoholic liver disease may be at particular risk. Anyone, including those without these diseases, should seek medical attention immediately if they develop symptoms of food poisoning after eating raw oysters.

WebMD Medical Reference Reviewed by Dan Brennan, MD on September 29, 2020

Sources

SOURCES:

Clinical cases in Mineral and Bone Metabolism: “Copper, magnesium, zinc and calcium status in osteopenic and osteoporotic post-menopausal women.”

ESHA Research, Inc., Salem, Oregon: “Oysters, eastern, farmed, raw, med.”

International Journal of Food Science and Nutrition: “Characterization of vitamin B 12 compounds from edible shellfish, clams, oysters, and mussels.”

Mayo Clinic: Vitamin B-12

National Public Radio: Who Ate the First Oyster? Cave May Hold an Answer

nih.gov: Selenium Deficiency

Clyde L. Mackenzie: History of Oystering in the United States and Canada, Featuring the Eight Greatest Oyster Estuaries

StatPearls: “Selenium Deficiency.”

The Korean Society for Bone and Mineral Research: “Should We Prescribe Calcium Supplements For Osteoporosis Prevention?”

The Journal of Nutrition: “Selenium Content of Foods”

U.S. Food and Drug Administration: The Danger of Eating Contaminated Raw Oysters

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