Bad reputations tend to stick like glue, even with foods. Continued negative press about a fruit, vegetable, or beverage is enough reason for many of us to banish it. Or maybe we indulge on occasion, but with a measure of guilt.

Take avocados and peanuts, for example. Not too long ago they wore a big scarlet "F" for too much fat. Yet as peanuts and avocados sat languishing on many people's bad-for-you lists, researchers discovered that the fat in these two foods, mostly the monounsaturated kind, is extremely good for the heart—and for health in general. And the good news didn't stop there. Researchers continue to uncover disease-fighting chemicals or new health roles for these foods.

For the common mushroom, the "bad" reputation is a tad subtler. They're not perceived as unhealthy. But they're often dismissed as diet food, something to eat that's low in calories but with little to brag about nutritionally. Truth is, scientists are finding that mushrooms contain powerful compounds that boost immune function and may fight cancer.

Now that scientists are looking beneath the surface at mushrooms, avocados, and peanuts—along with once-maligned eggs and coffee—redeeming qualities for each of these five foods are coming to light. They have culinary respect and a place at your table.

1. Avocado
Misconception: I shouldn't eat avocados because they're high in fat.
Why They're Good for You: A lot of attention centers on the fact that avocados are rich in monounsaturated fat, the heart-healthy kind. Yet scientists are now more interested in the active compounds in avocados that might help prevent cancer. One recent study found that those compounds can inhibit the growth of prostate cancer cells in the laboratory. While conducting the study, these researchers found avocados are loaded with a variety of antioxidants, including familiar disease-fighting compounds such as lutein, beta-carotene, and vitamin E.

Avocadoes - A Disease Fighter

Helps in the better absorption of anti-oxidants

Another recently discovered benefit is that avocados help the body absorb phytochemicals from other foods. Researchers from Ohio State University recently reported that pairing avocados with salsa or salad allows for better absorption of antioxidants in those foods. The lycopene in tomatoes or the beta-carotene in carrots may be better absorbed if there's a slice or two of avocado in the bowl. Scientists suspect that the fat content of avocados helps the body absorb these antioxidants.

Coffee - Benefits outweigh negatives

Helps memory, coordination and alertness

To name just a few: Arizona researchers recently discovered that caffeinated coffee helps improve memory in older adults. A new study from the United Kingdom suggests that small amounts of coffee consumed throughout the day can increase alertness and improve performance on all kinds of tasks, including those that require hand-to-eye coordination and attention to detail. Perhaps the most startling finding, however, links regular coffee drinking to a lower risk for type 2 diabetes. A new report in the Journal of the American Medical Association finds that people who drink a daily four to six cups have a 28 percent lower risk of developing this illness--which is fast becoming an epidemic in this country--than folks who drink less than two cups each day. Researchers arrived at those numbers by pooling the results of nine different studies from the United States and around the world. Speculation is that caffeine deserves the credit, though it could be an antioxidant compound called phenol chlorogenic acid.

3. Mushrooms
Misconception: Mushrooms are a low-calorie food with little nutritional benefit.
Why They're Good for You: They may be 90 percent water and have only 18 calories per cup, but mushrooms are getting serious scientific attention. Laboratory reports and animal studies show that compounds in mushrooms may do everything from bolster immune function to suppress breast and prostate cancers to decrease tumor size. And now, Penn State researchers find that mushrooms, from the humble button to the giant portobello, harbor large amounts of an antioxidant called L-ergothioneine. The scientific buzz is that fungi, for the moment, are the only foods that contain this compound.

Mushrooms - A Cancer Fighter

Large amounts of an antioxidant called L-ergothioneine.

While scientists work to figure out how these findings translate to dietary advice, Clare Hasler, Ph.D., a well-known phytochemical researcher and director of the Robert Mondavi Institute at the University of California, Davis, points out that mushrooms offer plenty of good nutrition, including a healthy helping of the blood pressure--lowering mineral potassium. "Most people might be surprised to learn that while orange juice is touted as one of the highest potassium foods, one medium portobello mushroom actually has more potassium," she says. "And five white button mushrooms have more potassium than an orange."

4. Peanut butter
Misconception: This creamy spread is an indulgence best enjoyed occasionally because it's high in fat and calories.
Why It's Good For You: At least five major studies now confirm that eating peanuts can lower risk for coronary heart disease. So it's no leap to think that peanut butter, which is essentially ground-up peanuts, confers the same benefits. "Suffice it to say that eating peanut butter or peanuts has been associated with lower total cholesterol, lower ldl or 'bad' cholesterol, and lower triglycerides, all of which are associated with lower cardiovascular disease risk," says Richard Mattes, Ph.D., a professor of nutrition at Purdue University.

Peanut Butter - Lowers Cholesterol

Filling snacks than rice cakes or pickles and tame hunger for a much longer period.

Even better, these health benefits seem to occur without promoting weight gain. One reason could be that peanut butter is a stick-to-the-ribs kind of food. When Mattes offered a group of volunteers seven different snack foods (including things like peanut butter, rice cakes, pickles, and almonds), study participants reported that peanut butter or peanuts were much more filling snacks than rice cakes or pickles and tamed hunger for a much longer period. Sure, peanut butter is high in fat and calories, but if a small amount can quell hunger, that might explain why dieters seem more satisfied with weight-loss plans that include the spread.

In fact, a study from Harvard finds that dieters allowed to include a small daily serving of peanut butter or other monounsaturated-rich fats, like peanuts or olive oil, in their eating plans lost weight and kept it off longer than dieters following a strict low-fat regimen. But dieting or not, Mattes says a tablespoon or two of peanut butter is all it takes to net a world of good benefits for both the heart and waistline without going overboard on fat and calories.

One more thing: Don't obsess about peanut butter being a big source of harmful-to-the-heart trans fats. A study conducted by the U.S. Department of Agriculture finds anywhere from zero to three-thousandths (0.0032) of a gram of trans fats in supermarket peanut butters. That's hardly enough to cause concern and 156 times less trans fat than the one-half gram the government requires manufacturers to disclose on food labels.

Eggs - A Complete Package

Inexpensive, Richest food sources of choline., contain the highest-quality protein.