When it comes to healthy snacks, popcorn already had high marks because it’s a 100%-whole-grain, high-fiber food that helps fill you up on relatively few calories.

Guess what? It’s even better.

Recent research reveals that America’s favorite snack is healthier than we previously thought.

But you have to make popcorn in a certain way to get all the health benefits and avoid turning it into just another junky snack.

And if you buy prepopped popcorn in bags in the potato chip aisle…well, you’d better know what to look for and what to avoid, or you’ll end up with something nearly as unhealthful as those potato chips!

THE SECRET INGREDIENTS IN POPCORN

Polyphenols (disease-fighting antioxidants) are present in popcorn—and also in other foods, such as fruits and vegetables. But until now, nobody had studied exactly how much polyphenol content there is in popcorn.

Researchers at The University of Scranton in Pennsylvania analyzed polyphenol levels in two air-popped varieties and two microwave brands of popcorn. When they averaged the numbers from all four types, they found that roughly two tablespoons of unpopped kernels or three to five cups of popped popcorn (one serving) contains 300 milligrams (mg) of polyphenols, while one serving of fruit contains, on average, 160 mg. In other words, popcorn contains roughly twice the amount of polyphenols as fruit! And to get 300 mg of polyphenols from regular corn, which contains 114 mg per serving on average, you’d have to eat about two and one-half servings. Popcorn wins again—by a long shot!

Then the researchers made another interesting discovery. They found that 98% of the polyphenols in popcorn are in the hull—the plasticky part in the middle of the popped piece of popcorn that often gets lodged in your teeth. “It makes sense, because we know that many polyphenols in fruits and vegetables are in the skin, and the hull is the kernel’s original outer coating—before the kernel pops and gets turned inside out,” said Joe Vinson, PhD, a professor of chemistry at the university and a coauthor of the study.

THE HULL TRUTH

Dr. Vinson went on to explain why he found the results so intriguing: “We’ve known that eating whole grains reduces risk for chronic diseases, and many scientists have chalked that up to the fiber, but the polyphenols may be responsible for at least some of the benefits.”

One reason that popcorn has more polyphenols than many fruits and vegetables is because of its low water content, Dr. Vinson told me. “Polyphenols get diluted in fruits and vegetables because they contain about 90% water, but popcorn has only about 2% to 4% water,” he said.

But there is one downside. The study also revealed that almost 100% of the polyphenols in popcorn aren’t “free,” meaning that they don’t automatically get absorbed into our bloodstream. “These polyphenols are bound to fiber, and fiber needs to be broken down and released by enzymes in the gastrointestinal tract,” said Dr. Vinson. (All fruits and veggies contain some “bound” polyphenols, but the percentage varies, he added.) In other words, it’s likely that some but not all of the polyphenol content in popcorn gets absorbed by our bodies. His next study, he said, will look at exactly how much does. In the meantime, Dr. Vinson said to chew your popcorn thoroughly, because enzymes in your saliva help break down fiber and make the polyphenols more easily absorbed.

DON’T UNDO THE BENEFITS

While dousing your popcorn with butter and salt may lower the glycemic index of the food, making it less likely to negatively affect your blood sugar and insulin levels, and won’t reduce the amount of polyphenols, it will raise the saturated fat, sodium and calorie content. If you overdo it, that’ll bring your popcorn down a few notches in the “healthy snack” department.

So it’s wise to avoid movie theater popcorn and prepackaged microwave popcorn bags (which are often loaded with fat, sodium and calories) and to instead eat air-popped popcorn, Dr. Vinson said. For a hint of flavor, he recommends spritzing popcorn with a light mist of water, lime juice or olive oil and then lightly salting it—the mist helps the salt stick and won’t make the popcorn soggy if you don’t overdo it. When you’re looking at different popped popcorn snacks in the supermarket, Dr. Vinson said to compare the fat and calorie content on the nutrition labels on the bags, which will help you decide which is a healthier choice. Choose the one with the lowest amounts.