HEALTH ON THE HALF SHELL
Prevent anemia
Boost immunity
Prevent heart disease
For most folks, shellfish like lobster, shrimp, scallops, and oysters are luxuries—foods to be reserved for special occasions. For one thing, shellfish are expensive, often costing twice as much (or more) as other fish. Shellfish also have a reputation for containing boatloads of cholesterol and a sea of sodium, both of which health-conscious diners usually try to avoid.
While it’s true that shellfish are high in cholesterol and sodium, these aren’t the health threats that scientists once thought they were, says Robert M. Grodner, PhD, professor emeritus in the department of food science at Louisiana State University in Baton Rouge. In addition, shellfish contain good amounts of vitamins, minerals, and other healthful compounds that more than offset their slight nutritional downside.
People who eat a lot of seafood fare even better than vegetarians when it comes to heart health. In one study, seafood eaters with high concentrations of omega-3s in their blood had significantly lower blood pressure and lower levels of cholesterol and triglycerides—blood fats that in large amounts can increase the risk of heart disease—than vegetarians who didn’t eat shellfish. Although many of the studies on omega-3s have focused on fish like salmon and mackerel, all fish, including shellfish, contain some omega-3s. In fact, eating six medium oysters five to seven times a month will provide all the omega-3s your heart needs.
Omega-3s love your heart and blood vessels. These fatty acids improve the electrical stability of the heart, guarding against deadly out-of-rhythm heart beats, notes researcher Dariush Mozaffarian, MD, DrPH, a cardiologist at Harvard Medical School and the author of a recent study finding that people who eat just two fish meals per week cut their risk of heart disease death by a respectable 36 percent. Omega-3s also make the linings of blood vessels function better and may improve the way cells respond to insulin, the hormone that tells cells to absorb blood sugar. Insulin problems raise the risk for diabetes and heart disease.
Scallops, as well as other shellfish, give your cardiovascular system a boost of vitamin B12—one serving of scallops packs a third of your daily needs. In its heart-protecting role, vitamin B12 helps your body deactivate the amino acid homocysteine before it can harm the thin inner lining of artery walls and set the stage for a buildup of artery-clogging plaque.
Shellfish are extremely perishable. Even when properly stored, they stay fresh for only a day or two. In addition, they cook very quickly. The difference between “just right” and “yuck” is often measured in minutes—or less. Here are a few tips for having the freshest catch every time:
Buy them live. Since shellfish go bad so quickly, it’s best to buy them live and cook them the same day. To keep them fresh after bringing them home from the store, be sure to store them in the refrigerator until you’re ready to start cooking.
Check for doneness. Few foods are less appetizing than undercooked shellfish. Lobsters and crabs turn bright red when they’re done, usually in about 15 to 20 minutes. Clams, mussels, and oysters are nearly done when the shells open. Letting them cook for another 5 minutes will finish the job.
What about cholesterol? Shrimp’s quirky cholesterol count—about 200 milligrams in 12 large ones, which is about the same as the cholesterol in one large egg—could make you pass up this low-cal delicacy. But for most of us, shrimp should get the green light: In a definitive Rockefeller University study, shrimp raised bad low-density lipoprotein (LDL) cholesterol by 7 percent, but also boosted good high-density lipoprotein (HDL) cholesterol even higher and decreased heart-threatening blood fats called triglycerides by 13 percent. Researchers concluded that when they took all of shrimp’s effects on blood fats into consideration, the bottom line is that shrimp’s a heart-smart treat. In contrast, eating two eggs raised LDL levels 10 percent but didn’t have the same positive effects on other blood fats.
And don’t be deterred by the sodium in shellfish, either. As you would expect of creatures from the sea, shellfish contain quite a bit—about 150 to 900 milligrams in a 3-ounce serving, depending on the type. But unless your doctor has suggested that you reduce the sodium in your diet, shellfish shouldn’t be a problem. One serving of shellfish is well within the Daily Value (DV) of 2,400 milligrams of sodium.
Aside from their role in protecting the heart, shellfish are incredibly rich sources of a variety of essential (and hard-to-find) vitamins and minerals. The large amounts of vitamin B12 in shellfish are important to your health for other reasons. The body uses this nutrient to keep nerves healthy and make red blood cells. When levels of vitamin B12 slip, the body (and mind) can literally short-circuit, causing memory loss, confusion, slow reflexes, and fatigue. In fact, what’s thought to be senility in older people is sometimes nothing more than a lack of vitamin B12.
Three ounces of crab contains 10 micrograms of vitamin B12, or 167 percent of the DV. Clams are even better, with 3 ounces—about nine small steamed clams—providing 1,400 percent of the DV.
With the exception of shrimp, shellfish also contain a lot of zinc, which is essential for keeping the immune system strong. Oysters are the best source, with six oysters containing about 27 milligrams, or almost 181 percent of the DV.
It’s sometimes hard to get enough iron from foods, which is why about 20 percent of Americans are low in this important mineral. But if you can muster up enough muscle to lift a mussel to your mouth, you’ll get much of the iron you need to help prevent iron-deficiency anemia. Three ounces of mussels provides about 6 milligrams of iron, or 60 percent of the Recommended Dietary Allowance (RDA) for men and 40 percent of the RDA for women.
Finally, many shellfish are good sources of magnesium, potassium, and vitamin C. The vitamin C is a great bonus because it helps the body absorb more of the iron found in these foods.
Shellfish are nutritious and delicious. But unless they’re prepared with care, they can also be dangerous.
In order to eat and breathe, shellfish such as clams and oysters filter 15 to 20 gallons of water a day through their shells. When the water contains bacteria, like the potentially harmful Vibrio vulnificus, the shellfish become contaminated and have the ability to make you sick.
This doesn’t mean that you can’t eat shellfish safely. Since the bacteria are readily killed by heat, cooking your catch will prevent potential problems. While this is bad news for lovers of oysters on the half-shell, there may be an alternative, at least in the future. Laboratory studies suggest that dousing raw oysters with hot sauce will kill the bacteria. Until further research is done, however, it’s best to be safe and eat your shellfish cooked.
Your brain’s got one of the highest concentrations of omega-3 fatty acids in your entire body. These long chains of fat molecules are woven into the membranes of brain cells, helping to send and receive the electrical and hormonal signals that translate into thoughts and feelings. “Researchers who look at problems like postpartum depression, schizophrenia, and depression are finding associations between lower levels of seafood intake and a greater likelihood of problems,” notes researcher Susan E. Carlson, PhD, professor of dietetics and nutrition at the University of Kansas Medical Center in Kansas City. “And lab studies are showing that when you change the composition of brain cell membranes, so that there’s less good fat in the mix, the membranes don’t send and receive signals as well.”
For low-pollution, eco-friendly shellfish, go for these varieties: farmed scallops, blue or New Zealand green mussels, butter or Pacific littleneck clams, Northern shrimp, and spotted prawns. Eat with confidence! These shellfish are low in contaminants and raised with environmentally friendly methods that don’t pollute surrounding waters or endanger other sea creatures, advises Bill Chameides, PhD, chief scientist for the Environmental Defense Fund. Dungeness and stone crabs are also recommended. But do exercise a little caution with lobster—mercury content means you should limit your children’s meals of lobster to two or three per month.
Eat them with vitamin C. Since your body is better able to absorb the iron in foods when you eat them with vitamin C, include vitamin C–rich foods such as broccoli or peppers on the shellfish menu.
Mix and match. Because shellfish are usually considered a luxury item, most people eat only a handful or two at a time. An easy way to include more of them in your diet is to toss them together in one big, briny stew, says Dr. Grodner. “It can be a mighty healthful meal,” he says.
In a Dutch oven, heat the oil over medium heat. Add the onions and garlic. Cook, stirring frequently, until the onions soften, about 5 minutes. Add the tomatoes (with juice), breaking up the tomatoes with the back of a spoon.
Add the water, vegetable juice, tomato paste, and oregano. Stir to mix. Bring to a boil, then reduce the heat to low. Cover and cook for 30 minutes.
Meanwhile, pick over the crabmeat, and discard any bits of shell. Place the crabmeat in a fine strainer. Rinse with cold water and drain.
Add the crabmeat, shrimp, and clams to the pot. Increase the heat to medium-high. As soon as the stew returns to a boil, remove it from the heat. Set aside, covered, until the shrimp are opaque in the center, about 5 minutes. Test by cutting a shrimp in half.
Sprinkle with the parsley.
Makes 6 servings
Cook’s Note: Serve the stew with plenty of whole-grain bread for dipping in the sauce.
Calories: 227
Total fat: 6.6 g
Saturated fat: 0.9 g
Cholesterol: 108 mg
Sodium: 481 mg
Dietary fiber: 2.7 g