An izakaya in Iwate Prefecture, Japan, has launched "Oyster Ice Cream," which quickly became a social media sensation. Some netizens jokingly called it "weird" and a "challenge to taste buds." This quirky dessert also indirectly promotes Iwate Prefecture's proud oyster culture. Would you dare to try it? In fact, oysters are rich in protein and minerals and are the "king of zinc" among foods. Let's explore the nutritional value of oysters!
Iwate Prefecture is one of Japan's top oyster-producing regions. A local izakaya, "Umippuku," recently launched visually striking "Oyster Ice Cream" at 600 yen per cup, quickly becoming a social media hotspot. The restaurant uses fresh oysters from Yamada Bay, placed atop smooth milk ice cream. They suggest eating it plain first, then drizzling with chilled concentrated clam broth and a little soy sauce to enjoy the complex layers of sweet, salty, and umami flavors.
Oysters are not just delicious; they are packed with protein and minerals. However, there are important considerations when eating them. According to the Hong Kong Centre for Food Safety and the Fuzhou Center for Disease Control and Prevention, per 100g of edible oyster meat:
Zinc is crucial for immune function, growth, reproductive health, and normal taste perception. Oysters contain 71.2mg of zinc per 100g, far exceeding beef tenderloin (4.73mg) and pork liver (3.68mg). However, the tolerable upper intake level for zinc for adults is 40mg per day. Long-term excessive zinc supplementation can interfere with the absorption of other minerals. Healthy adults can eat 1-2 oysters at a time; occasional oyster feasts are less concerning.
Oysters are also a good source of iron, selenium, and potassium, helping prevent anemia and maintain electrolyte balance and blood pressure. Three oysters can nearly meet an adult's daily selenium requirement. However, oysters are not low in sodium; hypertensive patients should reduce salt intake in other dishes when eating them.
Many people prefer the fresh, tender texture of raw oysters, but this carries significant safety risks. As filter feeders, oysters accumulate microorganisms from the water they grow in and can be contaminated with norovirus, Vibrio vulnificus, Salmonella, and other pathogens, leading to acute gastroenteritis and parasitic risks.
A previous expert case: a 50-year-old man ate raw oysters and developed a fever, low blood pressure, and confusion the next day. He was diagnosed with septic shock and acute kidney failure requiring emergency dialysis. The culprit was Vibrio vulnificus, a bacterium found in oysters. While it may only cause gastroenteritis in healthy people, in those with liver cirrhosis, chronic kidney disease, diabetes, cancer, or weakened immunity, it can rapidly enter the bloodstream, causing systemic septic shock.
Steaming is the preferred method to preserve nutrients compared to boiling or grilling. Once water boils, steam oysters in their shells for at least 8 minutes; this brings the center temperature to 96.1°C. Steaming for 10 minutes reaches 99.9°C. A minimum of 8 minutes ensures safety.
Oysters feed on natural algae and other phytoplankton. This can sometimes cause the oyster belly or gills to appear green, brown, or black. This dark/green material is natural food and is safe to eat. In other words, the entire oyster (except the shell) is edible.
Oysters are high in purines (282mg/100g), making them a high-purine food. People with hyperuricemia and gout should eat little or none. Additionally, oysters can accumulate heavy metals. However, products from reputable sources with traceable origins have lower risk. Still, sensitive groups like children, the elderly, and pregnant women should also avoid excessive consumption.
Sources: Umippuku Izakaya, Hong Kong Centre for Food Safety, Fuzhou Center for Disease Control and Prevention
