8 Health Benefits Of Oysters, Nutrition, And Side Effects

By Gayathri Vijay

When you think of oysters, what probably comes to your mind is eating them with a rind of a lemon. You may also want to eat them because they sound exotic. Well, that is because they are. They are the mothers of pearl, after all. Oysters are an impressive mix of essential vitamins and minerals. But what perks can oysters bring to your diet apart from the salty, zesty taste? This article discusses the health benefits and risks of eating oysters, how to add them to your diet, and who should avoid eating them. Keep reading.

What Are Oysters?

Oysters are a group of saltwater bivalve mollusks that dwell in marine or brackish environments. They are an important element of the ecology and filter contaminants from the water to provide habitat for other marine organisms.

Some types of oysters can be eaten either cooked or raw. These mollusks have a lot to offer in terms of health advantages, apart from their alleged aphrodisiac properties that help improve sexual drive.

Wondering what nutrients oysters contain? In the next section, we look at the breakdown of their minerals and vitamins.

Oyster Nutrition Facts

One serving (100g) of oysters contains (1):

Energy81kcal
Protein9.45g
Fat2.3g
Carbohydrate4.95g
Calcium8 mg
Potassium168 mg
Sodium106 mg

According to Dr. Rudolf Probst, a qualified medical doctor, 100g of oysters also provide (approx):

  • Vitamin D: 80% of RDI
  • Vitamin B1: 7% of RDI
  • Vitamin B3: 7% of RDI
  • Vitamin B12: 324% of RDI
  • Zinc: 605% of RDI
  • Copper: 223% of RDI
  • Selenium: 91% of RDI
  • Iron: 37% of RDI
  • Manganese: 18% of RDI
  • Phosphorus: 14% RDI
  • Magnesium: 12%of RDI

Oysters are also abundant in omega-3-fatty acids, which are essential for the antioxidant activity in the body.

The oysters you consume are marine-water mollusks, which contain most of the dietary nutrients you need. So, how do they benefit your health? Keep reading to know.

8 Health Benefits Of Oysters

1. May Help Reduce Body Weight

The proteins in oysters may help reduce or manage body weight. A study found that high-protein meals may promote satiety (feeling fuller), reduce energy intake, and help with weight loss. This function is majorly attributed to two hormones — cholecystokinin (CCK) and ghrelin (hunger hormone). Ghrelin, released by stomach walls, is responsible for the feeling of hunger, and its levels decrease after a meal. Similarly, CCK is produced in the upper small intestine after a meal, especially when protein-rich food is consumed. These decreased levels of ghrelin and increased levels of CCK signal the brain that enough food has been consumed and initiate satiety (2).

2. May Help Manage Blood Sugar Levels

As stated, protein-rich foods help improve satiety and reduce energy intake. This, in turn, helps manage blood sugar levels. Besides, a high-protein diet was shown to decrease the levels of hemoglobin A1c (HbA1c), a compound associated with blood sugar levels, in type-2 diabetes subjects. Moreover, these subjects also experienced weight loss and decreased blood pressure after following this diet for six months (3). However, more research is warranted in this regard.

3. May Help Improve Antioxidant Levels

Oysters have a special antioxidant called 3,5-Dihydroxy-4-methoxybenzyl alcohol (DHMBA). This phenolic compound may help reduce oxidative stress from the cellular level (4). However, research into the effects of DHMBA is still in the early stages. But the evidence so far suggests that it may help prevent cellular death due to oxidative stress (5).

Besides, another study indicates that DHMBA may also help prevent and treat liver diseases (6).

4. May Help Lower Cardiovascular Disease Risk

The omega-3fatty acids in oysters help reduce triglyceride levels in the blood. In fact, the FDA has approved two prescription omega-3 fatty acid agents to reduce triglyceride levels (7). A study also found that intake of oysters may help reduce cholesterol and total cholesterol levels besides increasing HDL (good cholesterol) levels (8). This improved lipid profile helps reduce cardiovascular disease risk.

Dr. Rudolf says, “They (oysters) are rich in omega-3 fatty acids, which are healthy cholesterol. They reduce the chances of plaque accumulation in the blood vessels and improve cardiovascular health. They also have vitamin E, which protects against heart disease.”

5. May Improve Sexual Drive And Treat Dysfunction In Men

Raw oysters are believed to have aphrodisiac (a food that helps improve sexual desire) potential. However, there is little scientific evidence to back this claim (9). Besides, zinc deficiency was found to reduce testosterone levels in men and may lead to erectile dysfunction. In a study, supplementation of zinc (rich in oysters) was found to increase testosterone levels in elderly men and improve libido (sexual desire) (10). Moreover, zinc therapy was also shown to improve sexual competence in male rats (11).

6. May Aid In Embryonic Growth

Omega-3-fatty acids are essential in determining the length of gestation in pregnant women and are the critical building blocks of the fetal brain and retina (12). In addition, they also may help improve fetal health, increase birth weight, and prolong the gestational period in cases where the mother might not fulfill the pregnancy for various reasons (13). However, more studies are needed in this regard to draw more definitive conclusions.

Note: Seafood is high in metals like mercury, and therefore, pregnant women usually avoid eating them and opt for supplements.

7. May Strengthen Bones

Oysters are rich in calcium, which is essential for maintaining bone health. Besides, their vitamin D content promotes calcium absorption into the bloodstream (14).

Bone density reduces as you grow older. It could also lead to osteoporosis and may cause frequent fractures (15). Oysters, added to a well-balanced diet, can help fortify your bones.

“Oysters are a rich source of vitamin D, copper, zinc, and manganese. These micronutrients, in combination with calcium, are thought to be the key to slowing or even preventing bone loss in older women due to osteoporosis,” says Nadia Charif, Health and Fitness Adviser, Coffeeble.

8. May Improve Immunity

Dr. Marie Ruggles, MS, RD, CN, CDE, says, “Zinc is an essential mineral for immune system support, especially antiviral activity. The generous amount of zinc from oysters will help block pathogens entering your cells, even if a virus has entered your body. Zinc also helps prevent viruses from replicating; this is very important since it is the replication that leads to illness.”

How can you reap these benefits of oysters? How frequently should you consume them? Let us find out in the following section.

How To Eat Oysters?

Generally, consuming six medium oysters per day is considered safe. Here are a few ways you can eat oysters:

  • Eat raw to get a briny flavor.
  • Cook partially by adding only a few seasonings. This changes the flavor profile slightly.
  • Coat in seasoned bread crumbs and shallow-fry them.
  • Steam oysters to add to pasta dishes.
  • Serve them in the shell topped with herbs and seasonings of your choice.

Tips: Choose oysters with shells that are not open. Also, remove the oysters that do not open while being cooked. It is also better to cook a few oysters at a time, to ensure all are cooked properly.

Note: Cooked oysters are a better option as the high heat kills bacteria and other possible disease-causing organisms.

As with any seafood, oysters too pose a few health risks if consumed in excess. What are they? Keep reading to know.

Side Effects Of Oysters

“Oysters feed by filtering water, and the vibrio found in water can concentrate in their tissues. Therefore, when you consume raw or undercooked oysters, vibrios can cause serious health problems, especially for people with liver disease,” Dr. Rudolf says.

Who should avoid it?

According to Dr. Probst, oysters can negatively affect

  • People with a low immune system
  • Breastfeeding mothers
  • Children
  • Pregnant women

Dr. Rudolf also says, “The bacteria and viruses from the sea can be harmful. They can cause Hepatitis A, vibrio infection, and norovirus infection.”

Since oysters are often eaten raw, they may cause food poisoning by passing on bacteria causing fever, nausea, diarrhea, and fever (16) (17).

Dr. Liana Casusi, MD, says, “Chemical contaminants like lead, cadmium, or mercury in oysters pose various other health risks. Because oysters contain high amounts of zinc, it is important to eat them in moderation. Too much zinc ingestion can cause poisoning and lead to vomiting, muscle cramps, stomach pain, and watery diarrhea. Also, eating raw oysters must be avoided by children, pregnant or breastfeeding women, and immunocompromised individuals at all costs. In addition, the CDC recommends that oysters only be eaten cooked. Also, individuals with seafood allergies must avoid eating them.”

Oysters are saltwater bivalve mollusks packed with essential nutrients. The many benefits of oysters can be attributed to their omega-3 fats and antioxidant compounds. Eating oysters may help reduce body weight, manage blood sugar levels, lower the risk of cardiovascular diseases, improve sexual drive, and treat erectile dysfunction. However, consuming them in raw or uncooked form may cause side effects in some people. In addition, individuals with low immune health, pregnant and lactating mothers should avoid intake of oysters. Hence, consume them in moderation and consult your doctor in case of any emergencies.

Frequently Asked Questions

Is it OK to eat oysters every day?

Yes, it is safe to eat oysters every day. They contain nutrients like vitamins B12 and copper, which can promote overall health.

Are oysters a superfood?

Yes, oysters are a superfood, as they are loaded with many vitamins, minerals, and omega-3 fatty acids. They are also low in calories and cholesterol.

Key Takeaways

  • A group of saltwater bivalve mollusks, oysters are found in brackish or marine environments.
  • They may help you reduce your body weight, manage your blood sugar levels.
  • It is better to consume cooked oysters as the high heat can kill not only bacteria but also other organisms that can cause diseases.

Sources

Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. Mollusks oyster Pacific raw
    https://fdc.nal.usda.gov/fdc-app.html#/food-details/174219/nutrients
  2. Effects of fat protein and carbohydrate and protein load on appetite plasma cholecystokinin peptide YY and ghrelin and energy intake in lean and obese men
    https://pubmed.ncbi.nlm.nih.gov/22556143/
  3. Effects of high-protein diets on body weight glycaemic control blood lipids and blood pressure in type 2 diabetes: meta-analysis of randomised controlled trials
    https://www.ncbi.nlm.nih.gov/pubmed/23829939
  4. Assessing the Protective Activity of a Recently Discovered Phenolic Compound against Oxidative Stress Using Computational Chemistry
    https://pubmed.ncbi.nlm.nih.gov/26624520/
  5. The Phenolic Antioxidant 3 5-dihydroxy-4-methoxybenzyl Alcohol (DHMBA) Prevents Enterocyte Cell Death under Oxygen-Dissolving Cold Conditions through Polyphyletic Antioxidant Actions
    https://pubmed.ncbi.nlm.nih.gov/34064340/
  6. A phenolic antioxidant from the Pacific oyster (Crassostrea gigas) inhibits oxidation of cultured human hepatocytes mediated by diphenyl-1-pyrenylphosphine
    https://pubmed.ncbi.nlm.nih.gov/23442659/
  7. Overview of Omega-3 Fatty Acid Therapies
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3875260/
  8. Effects of shellfish consumption on lipoproteins in normolipidemic men
    https://pubmed.ncbi.nlm.nih.gov/2349916/
  9. Exploring scientifically proven herbal aphrodisiacs
    https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3731873/
  10. Zinc status and serum testosterone levels of healthy adults
    https://pubmed.ncbi.nlm.nih.gov/8875519/
  11. Effects of zinc supplementation on sexual behavior of male rats
    https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2800928/
  12. Omega-3 Fatty Acids and Pregnancy
    https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3046737/
  13. Maternal fish and shellfish intake and pregnancy outcomes: A prospective cohort study in Brittany France
    https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2211746/
  14. Calcium and Vitamin D: Skeletal and Extraskeletal Health
    https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2669834/
  15. Muscle and Bone Mass Loss in the Elderly Population: Advances in diagnosis and treatment
    https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC6261527/
  16. Microbiological and Parasitic Exposure and Health Effects
    https://www.ncbi.nlm.nih.gov/books/NBK235727/
  17. Fish and shellfish
    https://www.nhs.uk/live-well/eat-well/fish-and-shellfish-nutrition/

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Gayathri is a biotechnology graduate with a keen interest in research-oriented writing, microbiology, genetic engineering, and psychology and cognitive science.... more

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