What makes a food a "superfood"? Is it produce with vibrant colors and dark, leafy greens? Or is the term simply a marketing tactic, with foods featuring shiny labels and buzzwords like "cleansing" or "detoxifying"? According to nutritionist Mikka Knapp from Bright Body Nutrition, there is a reason why superfoods are so special and there are many more superfoods out there than you might think, hidden in plain sight at the grocery store.

"There are so many underrated superfoods that we consider everyday produce," says Knapp. "Spinach and blueberries are perfect examples. No need for fancy powders and supplements." Other common produce items that are secret superfoods include pomegranates, beets and kale, among a long list.

Over the past few years, the term "superfood" has been reserved for exotic fruits and spices, touting widespread healing abilities, like açaí, gojiberries, maca and turmeric. But what makes these foods, which tend to be more expensive, so super?

"It all has to do with the antioxidant content," says Knapp. "Superfoods are rich in antioxidants, with abilities to kill harmful free radicals in the body that contribute to cancers, heart disease and diabetes."

Scientists measure a food's antioxidant level in several ways, but the most common is the FRAP (ferric reducing ability of plasma) analysis. This system measures how well a food can neutralize harmful free radicals in the body. The higher the FRAP value, the better.

What about superfood powders? You may have seen açai, maca and chlorophyll powder on the shelves at stores, but Knapp suggests to always check the expiration date of these products and keep them refrigerated.

"Chlorophyll, a type of blue-green algae in plants, provides many benefits, but you have to keep it cold or mold will grow," says Knapp. "The same goes for maca powder, a powerful Peruvian root similar to ginseng that regulates hormones, but it must be kept fresh and cold."

And what about turmeric, the powerful yellow-orange spice that flavors many dishes? Turmeric contains anti-inflammatory properties, which offer many benefits to overall health. But it also has a secret healing ingredient.

"Turmeric contains a component, curcumin, or BCM-95, which can be found in capsule form at health food stores," says Knapp. "When the curcumin is directly taken, you are receiving all the benefits of its anti-inflammatory properties."

Ultimately, superfoods can be found just about anywhere, whether you want to purchase a bunch of spinach from the produce aisle or powders from a health food shop or online. Both are equally beneficial, and provide the level of antioxidants needed to fight off disease. However, if you are on a budget, sticking to good old fruits and veggies is a safe bet.

"Superfoods can certainly become a marketing trap, if you are not careful," says Knapp. "Avoid the trendy status symbols, and consider speaking with a nutritionist if you are unsure about particular products."