Last Updated on November 26, 2021 by Michael Joseph
Crab is among the most popular forms of seafood in the world.
This shellfish features in many different cuisines worldwide, and it has a delicate and slightly salty flavor.
Further to this, crab offers a wide range of beneficial nutrients for very few calories.
This article provides a guide to crab, its nutritional properties, benefits, and potential downsides.
What Is Crab?
In the nutritional context, crab refers to the meat of a shellfish that belongs to the decapod group of crustaceans.
Crab is one of the most prevalent seafood options within the human diet. On this note, estimations claim that the global crab market will hit 3.7 million metric tonnes by 2026 (1).
Crab Meat Has An Impressive Nutritional Profile
Per 3.5 oz (100-gram) serving, cooked crab meat offers the following nutritional values.
|Name||Amount||% Daily Value|
As shown in the nutritional values above, crab meat is high in protein, low in fat, and contains no carbohydrates.
- Vitamin B12: 479% DV
- Folate: 13% DV
- Vitamin B6: 11% DV
- Vitamin C: 8% DV
- Niacin (B3): 8% DV
- Vitamin B5: 8% DV
- Riboflavin (B2): 5% DV
- Thiamin (B1): 4% DV
- Vitamin A (RAE): 1% DV
Aside from B12, crab contains a broad range of vitamins in small to moderate amounts.
- Copper: 131% DV
- Selenium: 73% DV
- Zinc: 69% DV
- Sodium: 47% DV
- Phosphorus: 22% DV
- Magnesium: 15% DV
- Potassium: 6% DV
- Calcium: 5% DV
- Iron: 4% DV
- Manganese: 2% DV
Crab contains high amounts of copper, selenium, zinc, and sodium.
It also provides a small to moderate amount of numerous other minerals.
Crab Provides Some EPA/DHA Omega-3
Crab contains 460 mg of long-chain omega-3 fatty acids per 3.5 oz (100-gram) serving (2).
This long-chain omega-3s are otherwise known as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
While 460 mg doesn’t make it quite as high in omega-3 as oily fish, it’s still a good amount compared to most other foods.
EPA and DHA are the active biologically available forms of omega-3, and they are thought to be important for human health. These fatty acids are linked to benefits related to their potential anti-inflammatory effects (4).
Crab Is a Rich Source of Selenium
While crab meat offers a wide variety of different minerals, its selenium content is particularly notable.
Selenium is a mineral required by selenoenzymes and selenoproteins that play a role in the antioxidant system (5).
Also, while selenium deficiency is relatively uncommon in much of the Western world, this is not true globally. It is estimated that between 500 million and 1 billion people have a selenium deficiency (6).
Furthermore, selenium insufficiency—an inadequate intake but not quite physiological deficiency—can be common in regions where the soil has low selenium content (7).
Selenium-rich foods, such as crab, may be particularly beneficial for those with an insufficient selenium intake. Per 3.5 oz (100-gram) serving, crab meat provides 40 mcg of selenium, equivalent to 73% of the daily value (2, 3).
Crab Tends To Contain Low Mercury Levels
On the positive side, crab contains one of the lowest mercury concentrations among common commercial seafood:
- The FDA conducted a monitoring survey on mercury in seafood over a period of 22 years. Across numerous samples, the mean mercury concentration of crab meat in this survey was among the lowest in seafood. The mean mercury concentration was 0.065 PPM, which compares favorably to popular fish like cod (0.111 PPM) and herring (0.078 PPM) (10).
- The National Defenses Resource Council (NDRC) categorizes crab as seafood with the ‘least mercury’ (11).
- According to the Environmental Defense Fund (EDF), common crab species are all low in mercury (12).
Interesting Fact: Crab Shells Can Be Edible
An interesting fact about crab is that, in some cases, the shell is actually edible.
Crabs that have recently shed their hard exoskeleton are called soft shell crabs because their new shell is soft and still developing.
The shells are still soft enough to eat at this point, and these crabs are sold as ‘soft shell crabs.’
Interestingly, due to their shell being edible, soft crab crabs offer some nutrients that aren’t present in regular crab meat. Among these are carbohydrates, a small amount of chitin fiber, and phytonutrients (13, 14).
Potential Downsides of Eating Crab
As we have seen thus far, crab is a nutritious food that provides a beneficial range of nutrients.
However, there are also some potential drawbacks to consider.
The first thing to be aware of is that, as a crustacean species of shellfish, crab allergies are relatively common.
This allergy is mostly due to a protein called tropomyosin present in crustaceans such as crab, lobster, and shrimp (15).
Individuals with a diagnosed or suspected crustacean allergy should not consume crab meat. For further information, here are some informative resources on crab allergy from reputable organizations:
According to the American College of Allergy, Asthma, and Immunology, individuals with a crustacean allergy can usually eat mollusks. However, they advise that such people should first seek advice from an allergist (16).
Crab is relatively high in dietary cholesterol; per 3.5 oz (100-gram) serving, crab meat contains 53 mg of cholesterol (2).
Firstly, it is worth pointing out that dietary cholesterol and blood cholesterol (often referred to as LDL or HDL) are different things. However, dietary cholesterol does seem to raise plasma levels of LDL cholesterol, and more significantly in some individuals than others (17, 18).
Further research on the potential health effects of increasing dietary cholesterol intake has produced mixed findings. For instance, a recent meta-analysis and review of the evidence have found a lack of evidence to draw firm conclusions into how dietary cholesterol affects heart disease risk (19, 20).
Historically, the Dietary Guidelines for Americans recommended no more than 300 mg of dietary cholesterol per day. However, this set limit was removed from the 2015-2020 guidelines onward (21).
For more information on this topic, the American Heart Association have written a scientific advisory on dietary cholesterol and cardiovascular risk, available here.
As with any isolated nutrient in food, whether it be sugar, saturated fat, salt, cholesterol, or anything else: it is important to consider the whole food. In other words, a particular food may be slightly high in salt or sugar, but it may also offer a lot of essential vitamins and minerals.
In other words, many foods that people may perceive as “bad” can have a net benefit. It is always worth remembering this, and food shouldn’t be judged as “good” or “bad” based on simple metrics.
Crab Can Be Expensive
While people widely enjoy crab for its taste and nutritional value, it tends to be quite expensive compared to regular fish, meat, and other protein foods.
There are many reasons for the relative expense of fresh crab; perhaps chief among these is that crab is highly perishable and requires careful storage. Crab fishing also tends to be a difficult (and often dangerous) job.
For a slightly more affordable option, canned crab still offers the same nutritional value as a fresh crab for a lower price.
Sometimes, chefs boil crab while still alive.
While this is not strictly a nutritional consideration, many people that care about animals have expressed concerns about this.
This is understandable as there is much debate over the ethical treatment of invertebrates like crab and whether they feel pain.
Crab offers protein and a wealth of vitamins and minerals for very few calories. Most people also love the delicious taste of crab meat, so it is understandably one of the most popular shellfish.
There are also some drawbacks of crab that mainly relate to potential allergies, affordability, and ethical concerns.
However, it is a tasty food that provides good nutritional value for those that can enjoy crab occasionally.
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