Dungeness crab is one of the most nutrient-dense proteins you can eat. A single 3-ounce serving delivers 19 grams of protein and just 94 calories, with barely any fat or carbohydrates. Beyond the macros, it’s packed with vitamins and minerals that many people don’t get enough of.
Protein With Almost No Fat
At 19 grams of protein per 3-ounce serving, Dungeness crab rivals chicken breast in protein density while coming in at roughly half the calories. It contains just 1.1 grams of fat and less than a gram of carbohydrate. That makes it one of the leanest animal protein sources available, useful for anyone trying to build or maintain muscle without extra calories.
Crab protein is complete, meaning it supplies all the essential amino acids your body can’t produce on its own: leucine, isoleucine, valine, lysine, methionine, and the rest. These are the building blocks your muscles need for repair after exercise and for everyday maintenance as you age.
Vitamin B12, Selenium, and Zinc
The micronutrient profile is where Dungeness crab really stands out. A 4-ounce serving provides a remarkable 431% of the Daily Value for vitamin B12. That’s more than four times what you need in a day from a single portion. B12 is essential for nerve function, red blood cell production, and DNA synthesis. People who eat little red meat or follow mostly plant-based diets are especially prone to running low on it.
The same serving covers 78% of the Daily Value for selenium, a mineral that supports thyroid function and acts as an antioxidant, protecting cells from damage. It also delivers 45% of the Daily Value for zinc, which plays a central role in immune defense and wound healing. Getting meaningful amounts of all three nutrients from a single low-calorie food is unusual.
Omega-3 Fatty Acids for Heart Health
A 4-ounce serving of Dungeness crab provides 450 to 540 milligrams of EPA and DHA, the two omega-3 fatty acids most strongly linked to cardiovascular benefits. These fats help lower triglycerides, reduce inflammation in blood vessels, and support a steady heart rhythm. The American Heart Association recommends eating seafood at least twice a week, and Dungeness crab comfortably fits that goal.
While fatty fish like salmon and mackerel contain higher concentrations of omega-3s, Dungeness crab still delivers a solid dose, especially considering how little total fat it has. You get the heart-protective fats without a significant calorie load.
Cholesterol and Sodium in Context
Shellfish tend to contain more cholesterol than finfish, and crab is no exception. Blue crab, a close relative, averages about 96 milligrams of cholesterol per 100 grams of meat. Dungeness falls in a similar range. For comparison, shrimp contains around 129 milligrams per 100 grams, and lobster about 146 milligrams. Crab is a moderate option among shellfish.
Current evidence shows that dietary cholesterol has less impact on blood cholesterol than once believed. For most people, eating shellfish a few times a week does not meaningfully raise cardiovascular risk, especially when the food also supplies omega-3s that actively benefit the heart. Sodium is worth watching, though. Crab meat naturally contains some sodium, and seasoned or pre-cooked preparations can push the numbers higher. If you’re limiting salt, rinse canned crab or season fresh crab yourself.
Mercury Is Very Low
Crab ranks among the lowest-mercury seafood options. FDA testing found a mean mercury concentration of 0.065 parts per million in crab, well below the threshold that raises health concerns. For context, swordfish averages close to 1.0 ppm and king mackerel around 0.73 ppm. Crab sits closer to salmon and shrimp on the safety spectrum. Pregnant women, nursing mothers, and young children, the groups most sensitive to mercury, can eat crab without concern about mercury accumulation.
Domoic Acid: The One Risk to Know
The primary safety concern with Dungeness crab isn’t a nutrient issue. It’s a naturally occurring algal toxin called domoic acid, which can accumulate in shellfish during harmful algal blooms. Eating contaminated crab can cause vomiting, nausea, diarrhea, and abdominal cramps within 24 hours. In severe cases, neurological symptoms develop within 48 hours, including confusion, dizziness, short-term memory loss, seizures, and in rare instances, coma. The memory loss can be permanent.
This sounds alarming, but state agencies in Washington, Oregon, and California regularly test shellfish and close harvesting areas when unsafe toxin levels are detected. Commercially sold Dungeness crab goes through this monitoring system, so your risk from store-bought or restaurant crab is extremely low. If you harvest your own, always check your state’s shellfish safety map or closure hotline before heading out. Washington State maintains a recorded biotoxin closure line at 1-800-562-5632.
Sustainability Matters Too
Dungeness crab caught in the Pacific Northwest using pots is rated a “Good Alternative” by Seafood Watch, meaning it’s a reasonable choice but not the most sustainably managed fishery available. The fishery has strong size and season limits that help maintain crab populations. Choosing pot-caught Dungeness over trawl-caught shellfish is generally the better environmental option, and a healthy ocean ecosystem contributes to healthier seafood overall.
How It Compares to Other Proteins
- Versus chicken breast: Similar protein, but crab adds omega-3s, far more B12, and more selenium. Chicken is cheaper and more convenient.
- Versus salmon: Salmon delivers more omega-3s per serving but also more calories and fat. Crab wins on B12 and zinc.
- Versus shrimp: Both are low-calorie and high-protein. Crab provides more omega-3s and less cholesterol. Shrimp is more widely available.
Dungeness crab is one of the most nutritionally complete single foods you can eat. High protein, minimal fat, extraordinary B12, strong selenium and zinc, meaningful omega-3s, and very low mercury. If the price and seasonal availability work for you, it’s a genuinely excellent addition to your diet.