Are Shrimp and Scallops Bad for Cholesterol?

Doctors and health experts used to warn people to limit their intake of shrimp, scallops, clams, and other shellfish because they were believed to be too high in cholesterol. That advice has changed. Now they know dietary cholesterol, like that in shellfish, has little or no effect on blood cholesterol for most people.

Your blood cholesterol is more influenced by the mix of fats and carbohydrates you eat. Shellfish, in fact, are excellent choices for a low-cholesterol diet. They have benefits that make them heart-healthy foods.

This article looks at the health benefits of shellfish, how to include it in a low-cholesterol diet, and what to look for when buying it.

Shellfish Benefits

Shellfish includes crustaceans, like shrimp and crab, and mollusks, like clams, oysters, and scallops. These foods, and seafood in general, are lower in calories than meat, a good source of protein, and very low in fat.

The fats they contain are monounsaturated and polyunsaturated fats. Those are commonly referred to as good fats. They improve blood cholesterol and lower your heart disease risk.

That's in contrast to saturated fat found in certain foods, which prompts your body to produce "bad" cholesterol and increases heart disease risk.

Shellfish are excellent sources of heart-healthy nutrients and do not appear to contribute to heart disease or high cholesterol. Shrimp is a good source of:

• Omega-3 fatty acids, which help lower cholesterol 
• Vitamin B12
• Vitamin D
• Potassium
• Magnesium
• Phosphorus

Scallops contain:

• Omega-3 fatty acids
• Magnesium
• Potassium
• Phosphorus
• Selenium
• Zinc

Clams are high in:

• Iron
• Zinc
• Selenium
• Potassium
• Vitamin B12

Shrimp, scallops, and clams are also low in mercury, so they can be enjoyed on a regular basis, per the U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA).

How Much Cholesterol Is in Shellfish?

This table lists the cholesterol content of different types of shellfish per 100 gram (3.5 ounce) serving.

For comparison, here is the cholesterol content of other protein-containing foods.

Although the cholesterol content of many of these protein foods is lower than some shellfish, the saturated fat content is much higher in beef, lamb, sausage, bacon, and cheese. Eating too much saturated fat causes the body to make more LDL cholesterol, which in turn, raises your risk of heart disease.

Keeping Shellfish Dishes Low in Cholesterol

Although shellfish is heart-healthy, some cooking methods may not be. The way shellfish are often prepared is what can turn a dish into a high-cholesterol one. 

These tips can ensure the shellfish you eat is heart-healthy and low in cholesterol:

• Use heart-smart cooking methods, such as stir-frying, grilling, pan-frying, searing, sautéing, or baking.
• Use olive oil, lemon juice, cocktail sauce, or seasonings to add flavor to your meals.
• Try seasonings such as garlic, tarragon, freshly grated ginger, and fresh herbs such as parsley, basil, and dill.

Avoid cooking methods that are high in fat, such as breaded and fried or deep frying. Try to avoid using butter because it is an unhealthy fat. Dipping shellfish in butter or dressing it with buttery sauces can make for a high-cholesterol meal.

Buying Shellfish

When shopping for shrimp, look for:

• Flesh that's transparent, not cloudy
• A sweet scent of fresh seawater
• Fresh-caught or frozen, wild-caught

If a package of shrimp smells fishy or like ammonia or bleach, do not use it.

Scallops in grocery stores are usually wet-packed. That means they're shucked on a boat and put in cold water to preserve them longer. They should be:

• White
• Firm
• Slightly moist
• Not shredded or mangled

Packaging should be firmly closed and not allow for any odor to escape. Much like shrimp, they should not smell fishy or have an ammonia- or bleach-like odor.

For clams, oysters, and all hard-shell mollusks, the shells should be tightly closed when purchasing. Give any open-shelled clams a tap. If they're alive, they'll close up. Any clams or hard-shell mollusks that don't close, or that have chipped or cracked shells, should be discarded.

In general, look for shellfish that are clean, covered in ice, and smell like the ocean.

Summary

Despite containing moderate to high levels of dietary cholesterol, shellfish can be a good part of a low-cholesterol diet. Saturated fat and carbohydrate content have a bigger impact on blood cholesterol.

Although a few types of shellfish are higher in cholesterol than red meats, they are very low in saturated fat (unlike red meats). Consuming two to three servings of fish and shellfish per week is recommended as part of a heart-healthy diet.

Common cooking techniques and recipes for shellfish involve breading, frying, butter, and heavy sauces. These can all contribute to high blood cholesterol, so look for heart-healthy ways to prepare shellfish.