Regardless whether you call them soft shell or blue crabs, these feisty devils provide a real treat. Originating in Maryland, the Carolinas and Louisiana, local water conditions produce slight nutritional variations. For example, the cold waters off the Maryland coast produce a crab with a higher fat content than crabs living in warmer waters.
Calories and Fat
One cup of meat from a soft shell crab cooked with moist heat has 112 calories and 1 gram of fat. While this isn't many calories for a high-protein entree, crab is not particularly filling because it is devoid of fiber. A meal including this food requires additional sources of fiber so that it can satisfy the Harvard School of Public Health's recommendation that people consume 14 g of fiber for every 1,000 calories.
The U.S. Department of Agriculture recommends that people consume 0.8 g of protein for every kilogram of body weight. This means that a 120-pound woman needs 43.63 g of protein every day. With 24.14 g of fiber, one cup of meat from a soft shell crab satisfies 55 percent of her daily protein requirement.
With 1.099 milligrams of copper, 1 cup of crabmeat satisfies 100 percent of the daily requirement for this mineral. Its 57.9 micrograms of selenium satisfy 88 percent of the daily selenium requirement, and its 5.14 mg of zinc meet 47 percent of the zinc requirement. A rich source of calcium, a serving of soft shell crab provides 123 mg of calcium, which satisfies 12.3 percent of the daily requirement for calcium. Lastly, this food provides 8.5 percent of the daily iron requirement for men and 3.77 percent of the daily iron requirement for women.
Although 1 cup of soft shell blue crab has insignificant amounts of vitamins A, C and K, its food is a rich source of B vitamins, providing more than 100 percent of the required pantothenic acid and 23 percent of the required niacin. With 0.031 mg of thiamin, 0.126 mg of riboflavin and 69 mcg of folate, a serving of soft shell crab cooked with moist heat satisfies 3.1 percent, 9.6 percent and 4.1 percent of the required amounts of these vitamins.
Patients with advanced kidney disease who must restrict their potassium and phosphorus should consult their nephrologist or renal dietitian before indulging because, with 316 mg phosphorus and 350 mg potassium, soft shell crab may be off-limits. The National Kidney Foundation classifies foods with comparable amounts of these minerals as high in potassium and phosphorus and urges patients to exercise caution.
The American Heart Association recommends that everyone limit their sodium consumption to 1,500 mg of sodium per day. With 533 mg of sodium, 1 cup of cooked soft shell crab meets more than one third of the daily ration of sodium. People eating soft shell crab should try to avoid the other high-sodium foods that are customarily served with crab, such as fries and corn on the cob served with salted butter and sprinkled with salt. Vigilance in this regard prevents heart disease.