Oysters are soft, large and flat shellfish that have been eaten by humans for thousands of years. In fact, ancient oyster shells have been found in prehistoric sites, such as caverns and caves.
Scientists have discovered oyster shells along the Georgia coast from 4,500 years ago and are researching how Native Americans sustained oyster harvests for centuries.
Oysters play an important role in the ecosystem as natural filters that remove pollutants from the water. They also provide a habitat for other sea species, such as mussels, barnacles and sea anemone.
In the culinary world, oysters are considered a delicacy. They are typically consumed raw and enjoyed because of their salty, meaty flavor. Plus, they’re touted for their nutrition profile and potential aphrodisiac effects.
There are some drawbacks to eating oysters. After all, they are filters and could contain bacteria that’s toxic to humans, causing inflammation of the stomach and other digestive complaints.
Oysters are a good source of protein, and they’re nutrient-dense, providing over 100 percent daily value for zinc, vitamin B12 and copper. They also contain omega-3 fatty acids, which are essential fats that boost heart health, support healthy joints and promote healthy cognitive function.
Additionally, oysters contain a phenolic antioxidant called 3,5-Dihydroxy-4-methoxybenzyl alcohol (DHMBA). Studies show that DHMBA works as a powerful free radical scavenger that provides antioxidant protection.
Six medium-sized raw oysters contain approximately the following:
- 57 calories
- 3 grams carbohydrates
- 6 grams protein
- 2 grams fat
- 76 milligrams zinc (509 percent DV)
- 16 micrograms vitamin B12 (272 percent DV)
- 3 milligrams copper (187 percent DV)
- 53 micrograms selenium (76 percent DV)
- 269 international units vitamin D (67 percent DV)
- 5 milligrams iron (31 percent DV)
- 0.3 milligrams manganese (15 percent DV)
- 113 milligrams phosphorus (11 percent DV)
- 39 milligrams magnesium (10 percent DV)
- 177 milligrams sodium (7 percent DV)
- 1.2 milligrams niacin (6 percent DV)
- 0.1 milligrams thiamin (6 percent DV)
- 3 milligrams vitamin C (5 percent DV)
- 131 milligrams potassium (4 percent DV)
- 38 milligrams calcium (4 percent DV)
- 0.7 milligrams vitamin E (4 percent DV)
1. Excellent Source of Zinc
Known as the best sources of zinc, three medium-sized oysters provide over 100 percent your daily recommended value. Consuming zinc regularly has a number of researched health benefits, including the mineral’s ability to fight oxidative stress, promote eye health, enhance immune function and aid nutrient absorption.
2. Provides B Vitamins
Oysters provide B vitamins, especially vitamin B12, which is an essential nutrient for healthy energy levels, memory, skin, mood and digestion. Vitamin B12 is needed to convert carbohydrates into usable glucose in the body, which is then used as a form of energy.
Vitamin B12 also helps the nervous system function properly and is needed for important cognitive processes, like learning and memory.
3. Contain Omega-3 Fatty Acids
Oysters contain omega-3 fatty acids, which are polyunsaturated fats (like DHA) that your body doesn’t make on its own but needs for several body functions. Omega 3s promote heart health by reducing high triglyceride and LDL cholesterol levels, lowering blood pressure, and preventing plaque buildup.
Omega-3 fatty acids also can help fight mental disorders, such as depression and anxiety, and they have neuroprotective effects on the brain. Additionally, these essential fats may help reduce inflammation and support healthy bones.
4. Good Source of Protein
Oysters are a decent source of protein, with about six grams in six medium-sized oysters. They contain all nine essential amino acids, which play a role in nearly every biological process, including hormone production, immune function and muscle growth.
Risks and Side Effects
Despite the impressive nutritional value of oysters, they are not exactly considered a healthy food. In fact, there are several potential concerns when consuming these shellfish, especially when raw.
A certain type of bacteria, called vibrio bacteria, are commonly found in filter shellfish like oysters. Therefore, there’s an increased risk of infection from consuming raw or undercooked oysters that contain pathogenic bacteria. Symptoms of an infection may include fever, stomach pain, nausea and vomiting, and even a dangerous blood infection.
Oysters may also have chemical contaminants, including mercury, lead and cadmium. Consuming too much of these heavy metals can be toxic to humans.
Studies also indicate that eating oysters may increase your risk of gastroenteritis, or inflammation of the stomach and intestines, which is caused by bacterial toxins and infections. Research suggests that oyster consumption may cause hyperuricemia, a condition involving elevated uric acid levels in the blood, and inflammatory conditions such as gout.
In addition to the potential health risks of eating oysters, oyster reefs, which are considered a keystone species that provides critical habitats for other sea organisms, are diminishing over time. The worldwide oyster population has dramatically declined over the last 100 years because of overexploitation, habitat degradation and climate change.
The overconsumption of these shellfish can have a negative impact on the ecosystem.
How to Prepare and Eat
Eating raw oysters is not recommended because of the risk of bacterial contamination. However, if you do eat these shellfish, the CDC provides the following safety tips:
- Cook oysters and other shellfish before eating.
- Wash your hands with soap and water before handling raw oysters.
- Avoid contaminating cooked shellfish with raw shellfish and its juices.
The safest way to prepare oysters is by boiling them for at least three minutes before consumption. They can also be baked, broiled or fried.
When shopping for oysters, purchase from a reputable company, and only choose shellfish with closed shells.
How do you use cooked oysters in recipes? They can be added to soups, stews, sauces, gumbos and casserole dishes. You can add cooked oyster meat to pasta, make oyster tacos or fry them for a crunchy addition to salads.
If you’re looking for a crunchy, salty and slightly fishy addition to recipes but want a healthier alternative to oysters, try seaweed instead. There are several types of seaweed that are packed with nutrients and can be consumed safely when eaten in small amounts.
Don’t overdo it on seaweed because it’s very high in iodine, and getting too much of this nutrient can be problematic.
Some of the best seaweed options include:
- Dulse: Dulse seaweed is commonly eaten fresh or as dry flakes. It can be added to omelets, salads and sandwiches, or prepared alone as a nutritious snack.
- Wakame: Wakame has a salty and slightly sweet flavor. It’s eaten fresh or dehydrated, often added to soups, stir-fries and salads.
- Kelp: Kelp is used in soups, pasta dishes and salads. There are also kelp sprinkles that can be added to recipes for a punch of nutrients.
- Oysters are shellfish that naturally filter pollutants from the seawater. They are considered a culinary delicacy, often eaten raw for their briny, meaty and slightly fishy flavor.
- Oysters are rich in several important nutrients, including zinc, vitamin B12, copper and selenium. They also provide omega-3 fatty acids and essential amino acids.
- Despite their nutritional value, oysters are not good for you because of their risk of bacterial contamination. They are prone to vibrio bacteria, which can be toxic to humans and cause digestive problems, inflammation and blood infection.
- If you want to eat oysters, stick to small amounts, and make sure they are fully cooked before consumption.