Health Benefits of Shellfish

Medically Reviewed by Christine Mikstas, RD, LD on June 05, 2023
4 min read

Adding seafood and shellfish to your diet can be very beneficial. People of all ages can eat many different kinds of seafood. Seafood and shellfish offer a variety of nutrients and protein which are important parts of a healthy diet. 

Shellfish have many nutritional benefits. There are also some risks that you should know about.

There are two kinds of shellfish: crustaceans and mollusks, or bivalves. Some common crustaceans that people eat include:

  • Crab
  • Lobster
  • Shrimp
  • Prawns
  • Crayfish
  • Barnacles

Some common mollusks are:

  • Octopus
  • Squid
  • Cuttlefish
  • Oysters
  • Clams
  • Mussels
  • Scallops
  • Abalone
  • Snails

Most experts agree that a balanced diet should contain two servings of fish per week. At least one of those servings should be oily fish. Oily fish are seafood like salmon, sardines, and trout. These kinds of fish contain long-chain omega-3 fatty acids. Omega-3s can help protect your heart.

There are weekly limits on how much of some kinds of seafood you should eat. The term "seafood" includes both fish and shellfish, so that means that there are recommendations for how much shellfish you can eat, especially for those who might become pregnant or breastfeeding and children between 1-11 years old. 

Shellfish have specific nutritional properties that can impact your health in different ways.

High in protein, low in calories. One of the best health benefits of shellfish is that they are a good source of lean protein. This protein is easy to digest when compared to other foods. Getting enough protein is essential when it comes to muscle growth and repair. It also helps you to stay fuller for longer.

One serving of clams is 3 ounces. You get 22 grams of protein within that serving. That is more than 40% of the daily recommended intake for a 2,000 calorie diet. Clams are also quite lean. One serving only has 126 calories and less than 2 grams of fat.

Shellfish like clams are high in protein and low in fat and calories. They can help you lose weight or maintain weight loss. Other shellfish are also low in calories. A 100 gram serving of cockles has just 79 calories. A serving of mussels has 74 calories. Both are far less than one serving of beef. 100 grams of beef contain 231 calories.

Vitamins and minerals. One of the biggest benefits of seafood is the number of vitamins and minerals that are in each serving. Seafood and shellfish are excellent sources of:

  • Vitamin E
  • Vitamin B6
  • Niacin
  • Phosphorus
  • Magnesium
  • Vitamin B12
  • Copper
  • Potassium
  • Zinc
  • Riboflavin
  • Iron
  • Selenium
  • Iodine

Seafood typically has lots of vitamins and minerals. Shellfish are especially high in minerals with antioxidant properties. 

Selenium can help to prevent cell damage and can potentially help process the mercury in your body. Iron helps to create red blood cells. Iodine aids your thyroid function. Zinc can help maintain your immune system and stimulate cell growth.

Fat and cholesterol. Another of the benefits of shellfish is that they are low in total fat and saturated fat. Seafood and shellfish are high in polyunsaturated fat. That’s the good kind of fat. Oily fish and shellfish also have omega-3 fatty acids which can help to prevent heart disease as well as babies’ vision and brain development.

The best sources of omega-3 fatty acids are oily fish like mackerel, salmon, and sardines. But shellfish also have a good amount. Several shellfish with good fats are:

  • Mussels
  • Crab
  • Squid
  • Oysters

Doctors agree that a healthy diet should include less than 300 milligrams of cholesterol each day. Most shellfish have less than 100 milligrams. Some lean varieties have less than 60 milligrams. Shrimp and squid are the exceptions. Both have higher levels of cholesterol.

There are many health benefits of shellfish. But there are certain risks that you should keep in mind.

Allergies.Shellfish allergies are quite common. Around 2% of people in the U.S. have them. These allergies usually last your entire life and don’t go away. If you eat shellfish when you are allergic to it, your body triggers your immune system. This causes an allergic reaction. Symptoms of shellfish allergies can range from mild to dangerous depending on how your body reacts.

Eating raw shellfish. Some types of seafood are safe to eat raw. But eating raw shellfish can be risky. Raw shellfish can cause illness or an infection called vibriosis. This is caused by bacteria that live in warm saltwater. You can get it when you eat raw or undercooked shellfish.

Symptoms of vibriosis start anywhere from 12 to 24 hours after eating raw shellfish. People commonly experience:

  • Vomiting
  • Fever
  • Chills
  • Diarrhea
  • Stomach cramps

Cases of vibriosis are usually mild. You should drink plenty of water to replace the fluids you lose through vomiting or diarrhea. Visit your doctor if you have severe or long-term symptoms. They may prescribe antibiotics if your symptoms are really bad or if your body fails to fight the infection without help.