Scallops are a type of shellfish eaten all over the world.

They live in saltwater environments and are caught in fisheries off the coasts of numerous countries.

The so-called adductor muscles inside their colorful shells are edible and sold as seafood. When prepared correctly, they have a slightly sweet taste and a tender, buttery texture.

Scallops are highly nutritious and may have impressive health benefits. However, people are often concerned about possible allergic reactions and the accumulation of heavy metals.

This article takes a detailed look at both the health benefits and possible dangers of eating scallops.

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Like most other fish and shellfish, scallops have an impressive nutritional profile.

Three ounces (84 grams) of steamed scallops pack (1):

  • Calories: 94
  • Carbs: 0 grams
  • Fat: 1.2 grams
  • Protein: 19.5 grams
  • Omega-3 fatty acids: 333 mg
  • Vitamin B12: 18% of the recommended daily value (DV)
  • Calcium: 9% of the DV
  • Iron: 15% of the DV
  • Magnesium: 12% of the DV
  • Phosphorous: 27% of the DV
  • Potassium: 12% of the DV
  • Zinc: 18% of the DV
  • Copper: 12% of the DV
  • Selenium: 33% of the DV

Scallops are an excellent source of several trace minerals, including selenium, zinc and copper. These minerals are important to human health, yet some people may not get enough of them.

Adequate selenium intake promotes a healthy immune system and proper thyroid function. Zinc is necessary for brain function and healthy growth, and copper may protect against diabetes and heart disease (2, 3, 4, 5, 6, 7).

Including scallops in your diet can provide you with these important trace minerals, as well as high-quality protein and anti-inflammatory omega-3 fatty acids.

Summary Scallops have trace minerals and other nutrients that are beneficial to human health. A typical 3-ounce (84-gram) serving of scallops is nutritious and packs less than 100 calories.

Low in calories and high in protein, scallops may be helpful if you’re trying to lose weight.

Research shows that reducing your total calorie intake while moderately increasing protein may promote weight loss (8, 9).

A 3-ounce (84-gram) serving of scallops provides close to 20 grams of protein for less than 100 calories (1).

Protein helps people feel full and satisfied, which can lead to a decrease in overall calorie intake. What’s more, it may increase metabolism and help your body burn more energy (8, 9).

A 26-week study in 773 people found that participants on a high-protein diet (25% of daily calories) lost on average 5% more of their body weight, compared to those on a low-protein diet (13% of daily calories).

In addition, the low-protein group gained an average of 2.2 pounds (1.01 kg) back (10).

Scallops and fish may also have unique properties that promote weight loss better than other protein sources (11, 12).

Summary Increasing your protein intake through foods like scallops may aid weight loss. Studies show that fish and scallops may even promote weight loss better than other types of protein.

Scallops contain certain nutrients that are important for your brain and nervous system.

Three ounces (84 grams) of scallops contain 18% of the DV for both vitamin B12 and zinc, as well as over 300 mg of omega-3 fatty acids (1).

Adequate amounts of these nutrients ensure proper nervous system development and may reduce your risk of mental conditions, such as Alzheimer’s and mood disorders (13).

One study found that babies born to women who had low vitamin B12 levels during pregnancy had slowed brain function nine years later. These children took over 20 seconds longer to complete cognitive tests than those of women with adequate B12 levels (14).

Another study showed that supplementing with B12 can reduce homocysteine levels by 30% and improve brain function. Too much homocysteine is linked to a higher risk of mild mental impairment (15).

Zinc also appears to be important to brain health. A 6-month study in rats showed that a 20% reduction in zinc levels in the blood led to mental and memory issues comparable to those associated with Alzheimer’s (16).

In addition to vitamin B12 and zinc, omega-3 fatty acids have many benefits for brain health and development.

Research has shown that developing babies who don’t get enough omega-3 fatty acids through their mothers’ diet may be at risk of developing attention deficit issues and psychiatric diagnoses (17).

Summary Scallops are rich in vitamin B12, zinc and omega-3 fatty acids. Getting adequate amounts of these nutrients is essential for brain development and associated with a reduced risk of mental decline and mood issues.

Scallops contain magnesium and potassium, two nutrients that keep your heart healthy.

Both play a role in relaxing your blood vessels. Therefore, sufficient levels of each vitamin may decrease blood pressure and prevent heart disease (18).

Low magnesium blood levels and intake have been linked to atrial fibrillation (a type of irregular heartbeat), high blood pressure and other heart issues (19, 20).

A study in more than 9,000 people found that those with magnesium levels below 0.80 mmol/L had a 36% and 54% greater risk of dying of heart disease and heart attack, respectively (21).

Summary Scallops are rich in potassium and magnesium. Sufficient levels of these nutrients may decrease your blood pressure and reduce your risk of heart disease.

Some people are highly allergic to fish and shellfish, including scallops.

An estimated 0.6% of US children under the age of 18 have an allergy to one or more kinds of fish. Some studies suggest a prevalence as high as 10.3% for shellfish allergies in people of all ages (22, 23).

In fact, shellfish are one of the most common food allergens. This type of allergy typically develops in adulthood and lasts for a person’s entire life (24, 25).

Scallops, oysters, mussels and clams cause fewer allergic reactions than crab, lobster and shrimp. Some people who are allergic to shellfish may only react to one group while tolerating other types (24).

Shellfish allergy is the result of your immune system reacting to the protein tropomyosin (22).

Symptoms of an allergic reaction to shellfish include (24):

  • Indigestion, diarrhea and vomiting
  • Tight throat and trouble swallowing
  • Hives over the entire body
  • Shortness of breath and coughing
  • Swollen tongue and lips
  • Blue or pale skin
  • Dizziness and confusion

In some cases, people may experience a life-threatening reaction called anaphylactic shock, which requires immediate treatment (24).

Summary Shellfish allergy is one of the most common food allergies. People with this condition may experience a reaction to eating scallops, which may include vomiting, hives, shortness of breath and possibly life-threatening complications.

Depending on their environment, scallops may accumulate heavy metals, including mercury, cadmium, lead and arsenic.

Heavy-metal build-up in you body can be dangerous.

Chronic exposure to arsenic has been linked to the development of cancer, while lead build-up can cause serious damage to major organs.

Mercury poisoning leads to decreased brain function, memory issues and depression. Finally, too much cadmium causes significant kidney damage (26).

Excessive amounts of each heavy metal present different risks. Since your body cannot excrete heavy metals, it’s important to limit exposure from food, water and environmental sources.

Unfortunately, seafood may contain varying amounts of heavy metals.

Research on canned scallops from Spain showed that they contained lead, mercury and cadmium. While the lead and mercury levels were well below the recommended daily maximum, the amount of cadmium was close to the maximum (27).

Another study on scallops from the coast of Canada found that cadmium levels were nearly double the recommended maximum for human consumption per day in some areas (28).

The few existing studies on heavy-metal concentrations in scallops suggest that they may differ by location but that most scallops are high in cadmium.

Additional research indicates that the amounts of accumulated metals may also vary between different parts of the scallop. Some metals may build up in non-edible organs and would thus not be as much of a concern for human consumption (29).

Summary Research shows that heavy metals pose a risk to human health and may build up in shellfish. Scallops appear to have lower levels of lead and mercury, but higher amounts of cadmium.

Due to their many health benefits, scallops can be a great addition to your diet.

They’re highly nutritious, rich in protein and low in calories. However, they can cause allergic reactions in people with shellfish allergies.

Depending on where they are caught, scallops contain varying levels of heavy metals and may have other contaminants.

Certain people should avoid scallops, including older adults, children, pregnant and nursing women or those who eat a lot of fish in general (30).

If you’re an otherwise healthy adult who is not allergic and does not need to worry about excessive heavy-metal consumption, eating scallops should be safe.

A simple way to prepare them is searing them with butter, salt and pepper.

Summary Scallops are a nutritious source of protein and generally safe to eat. Some people should limit consumption of scallops and fish in general due to allergies or heavy-metal accumulation.

Scallops are rich in protein and nutrients that promote heart and brain health.

They may accumulate certain heavy metals like mercury, lead and cadmium but are overall considered safe.

Unless you’re allergic or have been advised to watch your seafood intake, such as during pregnancy, there’s little reason to avoid scallops.

They make a healthy and delicious addition to your meals.