Oysters have always been a valuable food and records of their consumption date back to ancient Greek and Roman times. The shellfish is best known for its high content of zinc which promotes vitality and boosts male fertility. Eating oysters has benefits on energy metabolism as well as a result of a high content of vitamin B12 and further contributes to better immunity, stronger, healthier bones and teeth, thyroid health and hormonal balance. Although not without risks, eating oysters definitely has its health benefits.
What are oysters? Oysters are a type of shellfish related to clams, mussels and scallops. There are several types of oysters, including true oysters or edible oysters and pearl oysters, species that produce pearls. Edible oysters are also called simply oysters and represent a valuable food commodity. Aside from being an important source of nutrition, the species and its mollusk relatives help clean and preserve marine habitats by filtering water and removing nitrates and other chemicals from their environment, improving oxygen concentrations, water quality and favoring ecosystem balance.
What do oysters look like? Oysters often have a more irregular-shaped shell colored in grey, white, browns, seaweed green and amber, pale or lustrous. The two parts of the shell that enclose the edible inside are not always symmetrical. Some varieties are smaller in size, like Kunamoto or Olympia oysters. Some have a specific shape, like the Atlantic oysters which are teardrop-shaped. Some edible species have deep ridges on their shells, sharp edges or pointy indentations, whilst others are smooth.
What do oysters taste like? The taste of oysters depends on the species and properties of the water it has been living in. Some varieties like the Kunamoto oyster have a mildly sweet taste with delicate nutty flavors. European flats are meatier in texture with a persistent metallic taste and possibly slight fishy notes. Olympia oysters have an almost metallic flavor, copper-like, but with a slight sweet aftertaste.
Most raw oysters have a salty sea-like flavor to them or a mildly sweet, less briny aftertaste with either rusty, acidic, briny flavor notes or hints of cucumber or even melon. Texture ranges from meaty, crisp, soft, creamy, slimy to slightly elastic. Cooked oysters often have a more intense flavor and are more palatable compared to the raw ones because they absorb the flavors of the foods they are cooked with and lose some of their salty, sea water taste.
What are oysters good for? Like most foods, oysters are good for you when you eat them in moderate amounts and boast a superlative nutritional load. But contrary to popular practice, they are safest when eaten fully cooked. Here are 6 great properties and benefits of oysters:
1) Rich in vitamin B12. 100 g of raw oysters has between 150% to 400% of the RDA of vitamin B12 (8.75 micrograms to 16 mcg/100 g). Vitamin B12 protects the integrity of nerve cells, enhances memory and reduces the risk of developing degenerative diseases of the nervous system like Alzheimer’s and multiple sclerosis. Moreover, eating vitamin B12-rich foods like oysters helps the body synthesize amino acids from protein and use them as brain food.
2) Boosts energy and vitality. With a generous content of vitamin B12, but also B1, B2, B3, B6 and B9, oysters play a big role in energy metabolism, helping synthesize fats, protein and carbohydrates and releasing energy for the body. Eating oysters boosts vitality and improves energy levels.
3) Important source of zinc and vitamin D. Most oysters have between 17-40 mg of zinc/100 g, representing a superlative of 155% to almost 400% of the RDA of zinc. The mineral is vital for a good immune function and boost male fertility in particular. The vitamin D content of oysters further contributes to a stronger immune system and boosts female fertility, favoring pregnancy.
4) Source of iron, selenium, calcium, vitamins A and K. With a varied and generous nutritional profile, oysters are a great food for good health. The benefits of eating them include better thyroid health thanks to the selenium, elevated energy levels from the iron, improved eyesight from vitamin A, faster wound healing thanks to vitamin K and better bone density from calcium.
5) High in protein. 100 g of oysters have around 5-10 g of quality protein, rich in all essential amino acids. The amino acids in protein are needed for muscle gain and repairing damaged muscle fibers. Amino acid also help synthesize neurotransmitters which modulate nervous system activity and contribute to better mood, good appetite and better sleep.
6) Low fat content and low in calories. Raw oysters contain around 2 g of fat and 80 kcal per 100 g, making them a great food to incorporate in your diet. Fats are needed for brain development in babies in the womb, cognitive development of children and preventing early cognitive decline in adults. Fats also promote skin and hair health, while the low calorie content is good for losing weight.
Are oysters bad for you? There are instances when oysters pose health risks to consumers: oysters sickness due to bacteria and oyster allergy.
1) Oysters allergy. Some people are allergic to shellfish, including but not limited to oysters. Ingestion can potentially cause anaphylactic shock. Avoidance of the shellfish in all forms and preparations is strongly advised as is eating in or from food establishments where shellfish are commonly served due to risks of cross-contamination. Carrying all essential medication with you at all times is vital.
2) Oysters sickness. Oysters are known to carry a gram-negative bacteria called Vibrio vulnificus. This bacteria causes acute gastroenteritis with severe diarrhea, vomiting and stomach pain. Sepsis and serious illness is likely to occur in people with a compromised immune system or those suffering from chronic illnesses including, but not limited to diabetes and cancer or in children with an underdeveloped immune system. The bacteria is transmitted by eating raw or poorly cooked oysters and other shellfish or direct infection through an open wound (ulcer, scratch, sore etc.). Vibrio parahaemolyticus, another gram-negative bacterium in oysters also causes gastroenteritis.