Under The Shell

THE BALTIMORE SUN

In Wednesday's A La Carte, a listing of the nutritional content of crabs included incorrect figures. The tested crab contained 130 milligrams of cholesterol and 690 milligrams of sodium. In the accompanying story, the cholesterol content of an egg was incorrectly given. An egg contains about 213 milligrams of cholesterol.

The Sun regrets the error.

Less fatty than a hamburger. A good source of calcium, protein and vitamin A.

Nature's perfect food?

Not quite -- sodium and cholesterol are a problem, and there are always concerns about pollution -- but a meal of steamed blue crabs can be considered a healthful addition to most diets, according to experts who reviewed a test of crabs performed on behalf of The Sun.

Unlike tests used by the Food and Drug Administration and reference books, this one was done on crabs prepared the way Marylanders eat them: steamed with liberal amounts of salty seasoning. Several dozen crabs were purchased from a well-known Baltimore crab house, their meat removed and the sample tested by Strasburger & Siegel, an independent food-testing lab in Hanover.

"I think overall there is good news and bad news," said Dr. Benjamin Caballero, a nutritional biochemist and physician who is director of the Johns Hopkins Center for Human Nutrition.

On the plus side: crabs are low in fat, especially the saturated fat that doctors say is bad for the heart.

A half-cup of crab meat, equal to one large crab, yields only 2 grams of fat and 16 grams of protein. It also provides about 8 percent of the recommended daily intake of vitamin A, about half of the average diner's copper needs, and 10 percent of the recommended calcium.

"One hundred milligrams of calcium is hard to get from non-dairy sources," Dr. Caballero said.

"The bad news, of course, is it has a lot of cholesterol," he said. "People who are trying to control their cholesterol intake should eat crabs only occasionally."

A large crab's worth of meat yields 130 milligrams of the artery-lining cholesterol, meaning that three crabs give you more than the total 300 milligrams of cholesterol that doctors suggest daily for a healthy adult.

"That is the upper limit, ideally a person should be below that," Dr. Caballero said.

By comparison, shrimp has a little more cholesterol than crabs and lobster has twice as much. A hard-boiled egg -- a cardiologist's nightmare -- contains 500 milligrams.

"It depends on what else you eat. If you have a crab maybe you should have vegetables the rest of the day," he said.

Sodium-watchers may also want to steer clear of crab feasts or prepare them without the salty spices. Our sample produced almost 700 milligrams of sodium per large crab, about half of the 1,600 milligram daily ceiling recommended for a low-sodium diet or a third of the 2,100 milligrams recommended for the average adult.

"For people who are advised to reduce their sodium or those with even mild blood pressure problems, this may not be a good food for them to eat," Dr. Caballero said.

But for the rest of us, Dr. Caballero said, go ahead.

"If crabs are part of a diet with a variety of foods and if the diner is healthy, it is probably fine. If someone lives on an island and eats only crabs it might not be good," he said.

John Hetmanski, an executive chef, instructor at the Baltimore International Culinary College and former waterman, was pleased with the results of The Sun's study. He considers blue crab meat, especially from Maryland waters, to be an unusually versatile and fla-vorful food.

"It is not overwhelmingly loaded with vitamins but what it does have is good and is consistent with a balanced diet," Mr. Hetmanski said. "What I see here is a positive report. High protein, low fat. The sodium level caused me to raise an eyebrow."

Of course, the sodium can be reduced by using less -- or none -- of the traditional seasoning. But for some Baltimoreans, a crab without the spices is like a rowhouse without marble steps.

Harder to eliminate are the pollutants that have long been a source of concern in crabs because the voracious crustaceans tend to dine freely without regard to the industrial history of the area.

Periodic tests by state officials in Maryland have shown pollutants in crabs caught in state waters, but always at levels well below federal guidelines for safety. Better yet, the levels of lead, mercury, cadmium and other contaminates appears to be falling, said Mary Jo Garreis, administrator of the Maryland Department of the Environment's risk assessment program.

"We don't even find DDT anymore," she said.

But many of the crabs eaten by Marylanders come from other states, where contamination levels may not be as well-documented or that have had problems in the past. Texas authorities, for example, closed a central Gulf Coast bay to fishing and crabbing in 1988 because of mercury poisoning from a nearby aluminum factory.

But even then, consumers are protected by the blue crab's physiology: they have little body fat and live only a few years, factors that work against accumulation of pollutants, Ms. Garreis said.

The Sun's tests revealed lead, cadmium, mercury and chromium, but at levels FDA guidelines say are safe for a healthy adult to eat, based on average consumption. A test for common pesticides showed no or only trace contamination.

Dr. Jia-Sheng Wang, a research associate and expert on food-borne contaminants at Hopkin's School of Hygiene and Public Health, said the results of the tests for copper, a nutrient, chromium and mercury were not of concern.

The lead and cadmium in the sample, he said, "strikes me as a little high -- there should be none -- however they don't bother me."

Jackie Savitz, an environmental scientist at the Chesapeake Bay Foundation, said some pollutants may be of concern even when under the federal guidelines because those levels are based on average eating habits for healthy adults. Children and pregnant women, for example, may have lower tolerances. And tests should be conducted more frequently for areas of known contamination, such as the Inner Harbor, she said.

"We need to be looking at crabs in the Baltimore harbor a lot harder and we need to be looking at the most sensitive members of the population," Ms. Savitz said.

She eats crabs, but prepares them "Tangier style." This method requires cracking open the shell of a live crab and, using a water hose, washing away the internal organs in which pollutants tend to accumulate. The rest is then steamed.

Short of this, diners can also simply avoid the yellow "mustard" found within the crab. It is actually a fatty, filtering organ called the hepatopancreas that is the most likely place to find heavy metals and other pollutants in a crab.

"If you personally are concerned and you want to eliminate all the contaminates you possibly can, you probably do not want to eat the mustard," said Ms. Garreis, with the Maryland Department of the Environment.

But, she added, she eats crabs, mustard and all. "There is no food on earth that is perfectly safe."

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