Are Oysters Good for You? Benefits and Dangers

Beneficial to ecosystems and humans, oysters also provide an array of health benefits. What oysters lack in calories they make up for in their nutritional content, which includes vitamin B12, zinc, and a unique antioxidant.

Oysters are saltwater bivalve mollusks that live in marine habitats such as bays and oceans.

They’re a vital part of the ecosystem, filtering pollutants out of the water and providing habitats for other species, such as barnacles and mussels.

There are many different types of oysters — and their briny, flavorful meat is considered a delicacy around the world.

Though well known for their supposed aphrodisiac qualities, these mollusks have a lot to offer in terms of health benefits.

This article reviews the impressive health benefits — but also risks — of eating oysters and explains the best ways to prepare them.

Oyster nutrition facts

Oysters have a hard, irregularly shaped shell that protects a gray, plump inner body.

This inner body — known as the meat — is highly nutritious.

In fact, a 3.5-ounce (100-gram) serving of cooked wild eastern oysters provides the following nutrients (1):

• Calories: 79
• Protein: 9 grams
• Carbs: 4 grams
• Fat: 3 grams
• Zinc: 555% of the Daily Value (DV)
• Vitamin B12: 538% of the DV
• Copper: 493% of the DV
• Selenium: 56% of the DV
• Iron: 40% of the DV
• Manganese: 20% of the DV
• Phosphorus: 12% of the DV
• Vitamin E: 9% of the DV
• Riboflavin: 9% of the DV
• Calcium: 7% of the DV

Oysters are low in calories yet loaded with nutrients, including protein, healthy fats, vitamins, and minerals.

For example, a 3.5-ounce (100-gram) serving provides more than 100% of the DV for vitamin B12, zinc, and copper, plus a good amount of selenium, iron, and manganese (1).

These tasty mollusks are also a good source of omega-3 fatty acids, a family of polyunsaturated fats that play important roles in your body, including regulating inflammation, supporting heart and brain health, and protecting against type 2 diabetes (2, 3).

Oysters are packed with essential nutrients such as protein, vitamins, minerals, and omega-3 fatty acids. They’re particularly high in vitamin B12, zinc, and copper.

An excellent source of important nutrients

Oysters are packed with nutrients. They’re especially high in the following vitamins and minerals:

• Vitamin B12. This vitamin is critical for nervous system maintenance, metabolism, and blood cell formation. Many people, especially older adults, may have a vitamin B12 deficiency (4).
• Zinc. This mineral plays a vital role in immune health, metabolism, and cell growth. A 3.5-ounce (100-gram) serving of oysters provides more than 500% of the DV (1, 5).
• Selenium. This mineral helps maintain proper thyroid function and metabolism (6).
• Iron. Your body needs iron to make hemoglobin and myoglobin, proteins that carry oxygen throughout your body. Many people don’t get enough iron through their diet (7, 8).

In addition to their other various roles in health, many of these nutrients offer antioxidant protection.

For example, selenium is a powerful antioxidant that helps protect your body from oxidative stress, an imbalance that occurs when excessive amounts of free radicals are produced (6).

Oxidative stress has been linked to an array of chronic conditions, such as cancer, heart disease, and mental decline (9).

Zinc and vitamins B12 and D have antioxidant effects as well, boosting the protective benefits of oysters even higher (10, 11, 12).

Research shows that people who eat diets rich in antioxidants may have a lower risk of heart disease, type 2 diabetes, certain cancers, and all-cause mortality (13, 14).

Oysters are rich in zinc, iron, selenium, and vitamin B12. Some of these nutrients have antioxidant properties and may help promote overall health.

A high quality protein source

Oysters are an excellent source of high quality protein, with a 3.5-ounce (100-gram) serving packing in 9 grams of this filling nutrient (1).

They’re also a complete protein source, meaning they contain all nine essential amino acids your body needs (1).

Adding protein sources to meals and snacks can help promote feelings of fullness and encourage weight loss. Protein-rich foods stabilize hunger by increasing levels of fullness-promoting hormones like cholecystokinin (15).

High protein diets have been proven effective in boosting weight loss and may lead to greater weight loss than low fat or high carb diets (15, 16, 17).

Following a high protein diet may also be beneficial for people with diabetes.

For example, one review of 13 studies concluded that high protein diets could reduce insulin resistance — a condition that impacts the body’s ability to regulate blood sugar levels effectively — in people with type 2 diabetes. However, further studies are needed to support this (18, 19).

What’s more, high protein diets may reduce heart disease risk factors in people with type 2 diabetes.

A review of 18 studies in people with type 2 diabetes found that high protein diets significantly lowered triglyceride levels. High triglyceride levels are a major risk factor for heart disease (20).

High protein diets that include oysters may promote weight loss, improve insulin sensitivity, and reduce heart disease risk factors in people with type 2 diabetes.

Contain a unique antioxidant

Aside from being packed with beneficial nutrients such as vitamins, oysters contain a recently discovered, unique antioxidant called 3,5-Dihydroxy-4-methoxybenzyl alcohol (DHMBA) (21).

DHMBA is a phenolic compound that exhibits powerful antioxidant effects.

In fact, a test-tube study showed that it was 15 times more powerful in protecting against oxidative stress than Trolox, a synthetic form of vitamin E commonly used to prevent damage caused by oxidative stress (21).

Though more research in humans is needed, some test-tube studies indicate that DHMBA from oysters may be of particular benefit to liver health.

For example, one test-tube study demonstrated that it protected human liver cells from damage and cell death caused by induced oxidative stress (22).

Another older test-tube study found that DHMBA reduced oxidation of LDL (bad) cholesterol. Oxidation of cholesterol is a chemical reaction linked to the buildup of plaque in your arteries, known as atherosclerosis. It is a major risk factor for heart disease (23, 24).

Though these results are promising, more research is needed to determine whether DHMBA would be effective in protecting against oxidative stress in humans.

DHMBA is a powerful antioxidant found in oysters. It may help prevent oxidative damage and could support liver and heart health. Still, research is currently limited to test-tube studies.

Potential concerns

Though it’s clear that oysters offer impressive health benefits, some potential concerns exist — especially when consuming them raw.

May contain bacteria

Eating raw oyster meat poses a greater risk of bacterial infection.

Vibrio bacteria — including Vibrio vulnificus and Vibrio parahaemolyticus — can be concentrated in filter-feeding shellfish. Eating these shellfish raw can increase your risk of exposure (25).

Infections by these bacteria can lead to symptoms like diarrhea, vomiting, fever, and even more serious conditions such as septicemia — a serious blood infection that can lead to death (25).

According to the Centers for Disease Control and Prevention (CDC), 100 of the 80,000 people who get sick from Vibrio bacteria in the United States every year die from the infection (26).

Other contaminants

Oysters can also carry Norwalk-type viruses and enteroviruses that can pose health risks (27).

Additionally, these mollusks may contain chemical contaminants, including heavy metals such as lead, cadmium, and mercury (28).

Because of these potential health risks, children, people with compromised immune systems, and people who are pregnant or breastfeeding should avoid eating raw seafood (29, 30, 31).

Those who choose to eat raw oysters should be aware of these potential risks. At this time, there is no way to ensure that raw oysters are safe to consume, despite rigorous monitoring by both state and federal authorities.

This is why major health organizations like the Food and Drug Administration (FDA) and the CDC recommend that oysters only be eaten cooked (31, 32).

Other risks

Oysters contain an exceptionally high amount of zinc. While this mineral is important for health, consuming too much can be harmful.

Though zinc toxicity is most often associated with supplements, eating too many oysters too often can lead to negative health effects, such as reduced levels of the minerals copper and iron, which zinc competes with for absorption (33).

Additionally, those who are allergic to seafood or shellfish should avoid eating them.

Raw oysters can carry potentially harmful bacteria and viruses. Health organizations recommend eating cooked oysters rather than raw to avoid dangerous infections.

How to cook and enjoy

Because they can pose a health risk, eat raw oysters with caution. Always buy them from a reputable establishment — though this doesn’t guarantee safety (34).

Eating them cooked is much safer since cooking destroys harmful bacteria (31).

The CDC recommends cooking shucked oysters using the following methods (32):

• boiling them for 3 minutes or longer
• frying them in oil at 375°F (190°C) for at least 3 minutes
• broiling them 3 inches from heat for 3 minutes
• baking them at 450°F (230°C) for 10 minutes

Here are some safety tips to consider when shopping for oysters:

• Choose only oysters with closed shells. Discard those with open shells.
• According to the CDC and the FDA, oysters that don’t open during cooking should be discarded as well (31, 32).
• Don’t cook too many at once in a single pot, such as when boiling, as overcrowding can lead to some being undercooked.

Here are some delicious and easy ways to add oysters to your diet:

• Add cooked oyster meat to pasta dishes.
• Coat whole oysters in breadcrumbs and broil.
• Serve them cooked in their shells, topped with fresh herbs.
• Add them to seafood soups and stews.
• Fry panko-encrusted oyster meat in coconut oil.
• Steam them and top with lemon juice and butter.
• Coat oyster halves in a marinade of your choice and roast them on the grill.

To avoid potentially harmful bacteria, consume oysters thoroughly cooked rather than raw. Choose those with closed shells and discard any that don’t open fully during cooking.

The bottom line

Oysters are highly nutritious shellfish that offer a wide array of health benefits.

They’re packed with high quality protein, vitamins, minerals, and antioxidants — all of which benefit health.

Still, raw oysters can contain potentially harmful bacteria. To avoid getting sick, enjoy oysters cooked instead.

If you’re a seafood lover, try adding these tasty, nutrient-dense mollusks to your diet.

Just one thing

Try this today: In addition to oysters, there are many other nutritious shellfish available to consider adding to your diet. Check out this article for a list of a few other types of shellfish, along with the potential benefits and downsides of each.