It's gotten a bad rap. Butter has been blamed for making us gain weight and have heart problems. While it isn't the best option, local dietitians say it isn't as bad for us as we think. In honor of the 100th anniversary of the Iowa State Fair butter cow, we took on a few questions and debunked some myths about our favorite toast and bagel spread. What's better for you: Butter or margarine? What are the differences between the two? And how do you sort out all the different brands and options at the grocery store? Two local dietitians weigh in.

Myth: Butter is bad for you.

Fact: Like most things, butter in small doses isn't that bad for you. However, you should keep a few things in mind. Butter has about 100 calories per tablespoon. It's high in saturated fats, with about 7 grams in each tablespoon. Based on a 2,000-calorie-per-day diet, you should consume 15 grams or less of saturated fat. That means your daily intake of butter — if it's your only source of saturated fat — should be only about two tablespoons. Light butter truly is your best option. It has nearly half the calories of regular butter and less cholesterol.

Myth: Margarine is better for you than butter.

Fact Dietitians recommend choosing butter over margarine because it's more natural, made by churning milk into cream with salt and enzymes. While butter increases total cholesterol, margarine — made through the hydrogenation of vegetable oils into a solid form — specifically increases LDL cholesterol, the bad kind, and decreases the HDL cholesterol, the good kind. Margarine typically has fewer calories than butter, but dietitians call butter the "lesser of two evils" because it doesn't specifically raise LDL cholesterol.

Myth: When I eat out, I can tell which foods include butter.

Fact: Butter shows up in surprising places, dietitians said. Butter frequently is included in or used to prepare buffalo wing sauce, Alfredo sauce, steak, many bakery products, Italian breads and cheese sauces, mashed potatoes and gravy, to name a few. It's OK to request no butter in your food's preparation. For example, ask for your veggies to be steamed instead of sautéed.

Myth: I want to be healthy, but my only options are butter or margarine.

Fact: Not true. Most stores offer a range of spreads, from olive oil and infused oils to Brummel & Brown yogurt-based products that include vegetable oil and Smart Balance butters with omega-3 fatty acids. For butter and margarine substitutes for baking, try using equal parts of unsweetened applesauce or puréed pumpkin. Another option is to mix half butter and half a healthier option, like the ones mentioned above. If you can't stand the thought of eating something other than butter, try light butter.

Myth: Butter doesn't spoil. Fact It probably won't spoil if it's unrefrigerated overnight, but don't make a habit of keeping butter out for weeks at a time. Most butter manufactured today has enough salt in it to preserve it for a night or two.

Myth: Butter labels are difficult to understand, so I'll just read over them.

Fact: That's not so. Here's a typical butter label, with conversions:

2 cups = 4 sticks = 1 pound

1 cup = 2 sticks = ½ pound

½ cup = 1 stick = ¼ pound

¼ cup = ½ stick = 4 tablespoons

Sources: Jill Koegel, registered dietitian, owner of Certified Nutrition of Omaha and sports nutrition consultant for Creighton University Athletics. Lindsay Lannan, registered dietitian