Cholesterol and Food
True or false? The surest way to keep your blood cholesterol in check is to avoid foods that are high in cholesterol.
True or false? Cholesterol in the food you eat goes directly into your bloodstream and invariably raises your cholesterol levels.
True or false? You should avoid shellfish. All shellfish are high in cholesterol.
The answers? False. False. False. Cholesterol is one of the most misunderstood areas of nutrition. The cholesterol in food—called "dietary cholesterol"—is chemically the same as the cholesterol in your bloodstream, which is called "serum cholesterol." But there the similarities end. The body manufactures most of its serum cholesterol; some is also absorbed from the foods you eat. Dietary cholesterol is found only in foods of animal nature, never in foods from plant sources, even if they contain fat.
It's true that dietary cholesterol can influence the makeup of your serum cholesterol. But a far stronger influence is the amount of saturated fat in your diet. Saturated fat raises LDL cholesterol. LDLs increase the risk for heart disease. "Clearly, the issue is saturated fat," says Nancy D. Ernst, Ph.D., R.D., nutrition coordinator at the National Heart, Lung, and Blood Institute. Saturated fats come mainly from animal-based foods like meat, poultry, butter, whole milk, and whole milk products, and from coconut, palm, and palm kernel oils. These foods trigger the liver to make more LDL and total cholesterol.
Fat versus cholesterol
Fat is consumed in large quantities, cholesterol in tiny quantities. The American Dietetic Association says on the average, people consume 33 percent of their calories from total fat. But even if you ate three times the recommended limit of cholesterol, which is less than 300 mg per day, it would take more than a year to consume a pound. That's why fat is generally measured in grams, while cholesterol is measured in milligrams (a thousandth of a gram).
The USDA dietary guidelines recommend that total fat intake for adults be 20 to 35 percent of calories. A fat intake of 30 to 35 percent of calories is recommended for children 2 to 3 years of age and 25 to 35 percent of calories for children and adolescents 4 to 18 years of age. Remember that total fat equals saturated fats plus monounsaturated fats plus polyunsaturated fats. Broken down, the "no more than 30 percent guideline" looks like this: 7 to 10 percent of total calories from saturated fats; 10 to 15 percent from monounsaturated fats; and about 10 percent from polyunsaturated fats.
Monounsaturated fats include canola, nut, and olive oils. Polyunsaturated fats include corn, safflower, sesame, sunflower, and soybean oils, and often are the fat in seafood.
Additionally, no matter what the calorie intake, the cholesterol guideline for healthy individuals is no more than 300 mg per day.
Trans fat, found in commercially baked goods and in margarine, as well as in the oils most restaurants use, also raises the cholesterol levels in your body. Most trans fat in the diet come from hydrogenated fats.
"Forbidden" foods—notably eggs, liver, and shellfish—can have a place in a "heart-healthy" diet if used wisely. Some—notably crabs and lobsters—are actually among the healthiest choices you can make. Here's a look at these foods.
Eggs: All they're cracked up to be
It's true that eggs pack a hefty dose of cholesterol—about 213 mg for a large egg, compared with a recommended daily limit of 300 mg. But they're relatively low in saturated fat compared with most cuts of meat. And they're an excellent source of essential nutrients, including calcium, iron, vitamins D, A, and B, and a healthy amount of protein. But if you're like many Americans, you may believe that eggs are tiny time bombs of cholesterol.
The fear of eggs stems from an incorrect but deeply ingrained assumption that cholesterol in foods raises "serum" levels of cholesterol. But dietary cholesterol, though clearly a factor, has at most only a modest effect on blood cholesterol levels. Just how much effect it has depends upon many factors, including your genetic makeup, exercise habits, and lifestyle choices.
Where your diet is concerned, saturated fat—not cholesterol—is the predominant consideration. "Saturated fat has a more powerful and more straightforward effect on serum cholesterol," says Margo A. Denke, M.D., an internal medicine specialist in Dallas. That's good news for egg lovers, since one large egg has less than 2 grams of saturated fat—less than a small roasted chicken leg with skin.
Moderation is key. There's no limit on egg whites, however, since all the fat and cholesterol is in the yolk.
Shellfish: Good food with a bad reputation
Anyone who's trying to cut his or her cholesterol knows that shellfish are a no-no, right? Wrong. "People think shellfish is high in cholesterol, but that's just not the case," says Dr. Ernst. In fact, most shellfish are slightly lower in cholesterol than meat and poultry. And in the more crucial category—saturated fat—shellfish are significantly better for you.
Shellfish have minimal saturated fat content and very low total fat—less than a gram per 3-ounce serving. Three ounces of crabmeat, for example, have only 43 mg of cholesterol and only 0.3 gram of saturated fat. Three ounces of steamed lobster meat? Just 61 mg of cholesterol and 0.1 gram of saturated fat. That's about the same amount of saturated fat as an apple. You'd have to eat more than 10 pounds of most shellfish before you would reach your daily fat limit. By comparison, a 3-ounce hamburger has 76 mg of cholesterol and a whopping 7 grams of saturated fat. Just three burgers may fill your daily fat quota.
Crab, oysters, mussels, scallops, and clams are similarly low in fat, adding no more than 30 to 50 mg of cholesterol per 3-ounce to 3.5-ounce serving.
So why did shellfish get such a bad reputation? Perhaps it's the company it keeps. "People have been told not to eat lobster because they dip it in butter," says Wahida Karmally, R.D., a New York nutrition expert. So hold the butter. And watch out for fried shellfish, as well. Frying can turn a low-fat dish into a high-fat monster. Instead, try steaming shellfish, Karmally suggests. Serve it with lemon and spices. Served that way, most shellfish are unlikely to make a big dent in your daily quota of either fat or cholesterol.
An exception is shrimp. It's low in fat but relatively high in cholesterol, at approximately 140 mg per 3-ounce serving. Six ounces can put you near your daily cholesterol ceiling of 300 mg. Still, "eating shrimp is absolutely OK," says Karmally. Just do it in moderation.
Organ meats: Liver lovers take note
Although organ meats are not exactly an American dinnertime staple, their high cholesterol content has deterred some people from partaking of them at all. And reasonably so, because a 3-ounce serving of liver, the most commonly eaten organ meat, chalks up more than approximately 400 mg of cholesterol. That would put you, in just one meal, over the 300 mg daily limit.
Does that mean you can never eat liver?
To the contrary. The 300 mg cap, explains Dr. Denke, is meant as a guide, not a hard and fast rule. "It's your diet over time that's important," she says. "You can still eat liver, but you should weight the other elements of your diet to balance it out over time, keeping your average daily cholesterol intake over the course of a few days or a week at 300 milligrams."
Dr. Denke advises that you can keep your overall diet in balance by remembering this general rule: 25 mg of dietary cholesterol has roughly the same cholesterol-raising potential as 1 gram of saturated fat. By that measure, the 400 mg of cholesterol in a 3-ounce serving of liver is roughly equivalent to eating 16 grams of saturated fat.
Whether you choose the steak or the liver, you're going to put a significant dent in your fat budget for the day. That means you should avoid fatty foods for a bit. Even two tablespoons of salad dressing could put you over. "Go vegetarian for the next meal or two," Karmally suggests.
The bottom line is: If you love liver, there's no reason to give it up entirely. But don't go overboard. "Try to eat small portions," advises Karmally, "and use beans, grains, rice, and pasta to stretch the meat."