shellfish – which can be divided into crustaceans and mollusks – are rich in lean protein, healthy fats, and micronutrients.
shellfish have been consumed all over the world for centuries.
they are rich in lean protein, healthy fats, and minerals. eating shellfish regularly can boost your immunity, help with weight loss, and promote brain and heart health.
however, shellfish are one of the most common food allergens, and some species may contain contaminants and heavy metals.
this article reviews the different types of shellfish, their nutritional, health benefits, and possible dangers.
Species of shellfish
As the name suggests, shellfish are animals that live in water and have a shell or shell-like appearance.
They can be divided into two groups: crustaceans and mollusks. crustaceans include shrimp, crayfish, crabs, and lobsters, while clams, scallops, oysters, and mussels are examples of mollusks (1).
Most shellfish live in brackish water, but the name also refers to species in freshwater.
Shellfish can be bought in grocery stores and restaurants around the world, but some areas are known for certain species. for example, lobster is a popular food in the northeastern united states, while shrimp is a staple of the country's southern cuisine.
Most types of shellfish can be eaten steamed, roasted, or fried. some — like oysters and clams — can be eaten raw or half-cooked. their taste ranges from sweet to salty, from subtle to delicate – depending on the type and cooking method.
Summary: the term "shellfish" includes shrimp, crayfish, crabs, lobsters, clams, scallops, oysters, and mussels. shellfish can be made in different ways and are eaten all over the world.
a Nutritious powerhouse
Shellfish are low in calories and are rich in lean protein, healthy fats, and many micronutrients.
This is a nutritional comparison of different types of shellfish in 3 ounces (85 grams) servings (2):
| type | calorie | protein | fat |
| shrimp | 72 | 17 g | 0.43 g |
| crayfish | 65 | 14 g | 0.81 g |
| crab | 74 | 15 g | 0.92 g |
| lobster | 64 | 14 g | 0.64 g |
| clam | 73 | 12 g | 0.82 g |
| scallops | 59 | 10 g | 0.42 g |
| oysters | 69 | 8 g | 2 g |
| mussels | 73 | 10 g | 1.9 g |
Most of the fat in shellfish is found in the form of omega-3 fatty acids, which have a range of health benefits, such as improved brain and heart health (4, 5).
What's more, shellfish are rich in iron, zinc, magnesium, and vitamin B12 — all of which play an important role in your body. For example, 3 ounces (85 grams) of oysters contain almost 100% of their daily value (DV) of zinc (2).
Keep in mind that shellfish are most nutritious when steamed or roasted. breadcrumbs or fried shellfish may contain extra calories, refined carbohydrates, added salt, and other unhealthy ingredients.
Summary: Shellfish are low in calories and rich in protein and omega-3 fatty acids. They also contain large amounts of certain micronutrients, including iron, zinc, magnesium, and vitamin B12.
Potential health benefits
Because of their impressive nutritional profile, shellfish may be good for your waistline, brain, heart, and immune system.
May help with weight loss
Shellfish are low in calories and are rich in lean protein and healthy fats – making them great foods for weight loss.
Protein-rich foods make you feel full and satisfied, which may prevent you from consuming too many calories, which can help you lose or maintain weight (6, 7).
What's more, because of their omega-3 fatty acid content, fish may cause greater satiety and contribute to weight loss compared to other high-protein foods (8, 9).
A study of overweight adults found that people who consumed more omega-3 fatty acids in a calorie-restricted diet felt significantly fuller after meals than those who consumed less omega-3s in the same diet. (9）。
May promote heart health
Shellfish are rich in heart-healthy nutrients, including omega-3 fatty acids and vitamin B12.
several studies have shown that eating omega-3 fatty acids in fish and shellfish has been linked to a reduced risk of heart disease. this may be because omega-3 has anti-inflammatory effects (10, 11, 12).
a study of 18,244 healthy men in china found that people who consumed more than 7 ounces (200 grams) of omega-3 shellfish per week were 59% less likely to die of heart disease than those who consumed less than 1.74 ounces (50 grams) per week (13).
In addition, inadequate intake of vitamin B12 is associated with blood levels of homocysteine, a protein that increases the risk of heart disease. Therefore, consuming foods rich in vitamin B12 can prevent heart disease (14, 15).
Good for your brain
The same nutrients in shellfish that are good for the heart are also essential for brain health.
In fact, several studies have identified inadequate levels of vitamin B12 and omega-3 in the blood as risk factors for brain development problems in children and healthy brain function in adults. (16, 17, 18, 19）
Some studies have also shown that vitamin B12 and omega-3 fatty acids may enhance each other's activity, thereby promoting brain health.
A study of 168 older adults with mild mental disorders found that B vitamins slowed the progression of brain problems in people with higher levels of omega-3 fatty acids in their blood compared to those with lower levels of omega-3 fatty acids in their blood. (20）。
Rich in nutrients that enhance immune function
Some types of shellfish are rich in zinc which boosts immune function.
This mineral is necessary for the development of the cells that make up the body's immune defenses. it can also act as an antioxidant, preventing damage caused by inflammation (21).
A study of 62 healthy adults over the age of 90 found that zinc deficiency was associated with reduced activity of certain immune cells. (22）。
eating shellfish regularly — especially oysters, clams, mussels, lobsters, and crabs — can improve your zinc status and overall immune function.
Summary: Shellfish are rich in protein and healthy fats that may help with weight loss. They are also rich in nutrients that promote brain, heart, and immune system health — omega-3 fatty acids, vitamin B12, and zinc.
Possible drawbacks
Although shellfish are rich in nutrients, there may be some drawbacks to eating them.
Accumulation of heavy metals
Shellfish may accumulate heavy metals, such as mercury or cadmium, from their environment.
Humans cannot excrete heavy metals. overtime, the accumulation of these compounds in your body can lead to organ damage and other health problems (23).
One study found that cadmium levels in shellfish in some areas may be twice the recommended daily intake for humans. shellfish may also contain mercury but are Usually relatively large fish (24, 25).
The FDA recommends that adults eat 3-5 ounces (85-140 grams) of low-mercury fish twice a week. If you eat at least or less shellfish per week, heavy metals don't have to worry (25).
Foodborne illness
Consumption of contaminated shellfish can lead to foodborne illness.
In fact, from 1973 to 2006, mollusks— such as clams, scallops, oysters, and mussels— accounted for more than 45 percent of seafood-related foodborne illness cases in the united states (26).
Shellfish food poisoning can be caused by bacteria, viruses, or parasites acquired from their environment (26).
Pathogens multiply in large numbers in raw shellfish and improperly refrigerated shellfish. therefore, proper storage and cooking of shellfish is an effective way to prevent foodborne illness.
Pregnant and lactating women, the elderly, and people with compromised immune systems should avoid raw or improperly prepared shellfish.
Anaphylaxis
Shellfish are one of the top eight food allergens in the united states (27, 28).
shellfish allergy usually occurs in adulthood, but can also occur in childhood.
Symptoms of an allergic shellfish reaction include (29):
- vomiting and diarrhea
- stomach pain and cramps
- swelling of the throat, tongue, or lips
- measles
- shortness of breath
In some cases, people who are allergic to shellfish may experience life-threatening anaphylactic shock that requires immediate treatment (29).
summary: Shellfish may contain different levels of heavy metals that can build up in your body and cause health problems. in addition, shellfish can cause foodborne illness and allergic reactions.
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Concluion:
Shellfish – which can be divided into crustaceans and mollusks – are rich in lean protein, healthy fats, and micronutrients.
They may help with weight loss, boost immunity and promote brain and heart health. nevertheless, shellfish may contain heavy metals and cause foodborne illness and allergic reactions.
Still, shellfish can be a nutritious and delicious addition to a balanced diet for the healthiest of people.