There's nothing quite like eating a handful of freshly picked blueberries on a warm summer day, each bite bursting with flavor and cancer-fighting antioxidants, bone-building minerals and must-have vitamins. Surprisingly, you can get nearly the same nutrition from a bag of frozen blueberries. Despite what you may have heard, fresh produce may not be more nutritious than frozen produce. Even canned fruits and veggies are a good source of many of the nutrients found on the produce aisle of your grocery store, says Gene Lester, a U.S. Department of Agricultural plant physiologist who specializes in the nutritional content of plants and fruits.

"Nutrition is not always as straight forward as you'd like it to be," Lester says.

Many things factor into produce's nutritional makeup: When it's picked, the method of preservation – even the way a vegetable or fruit is prepared. The produce with the highest nutritional content is probably that which you've grown or picked yourself and eaten on the spot. But even that isn't completely clear.

For example, vegetables grown in sandy soil are up to five times less nutritional than those grown in clay soil. "If you had fresh produce from a farm that's just down the street, but the produce is grown on sandy soil, it might have less nutrients than produce sold at a grocery store," Lester says.

What keeps nutrients in preserved foods on par with fresh produce? Fresh fruits and veggies may be picked before they reach their nutritional peak, so that they can ripen while in transit. In contrast, frozen fruits and vegetables are often picked at a more mature state and then flash frozen. Canned vegetables go through a similar process, sealing in many nutrients.

Still, the preservations methods are not without their drawbacks. Some important nutrients like B vitamins and vitamin C are water-soluble; in canned goods, those vitamins will leach into water the produce is packed in. Exposure to air and light – either in your fridge or in a fruit bowl on your kitchen counter – can also limit the shelf life of some vitamins.

But other nutrients – including vitamins A, D, E and K, and fiber – survive this process.

The important thing, Lester says, is to eat more vegetables and fruit, whether they’re canned, frozen or fresh. "The more mouthfuls of vegetables you eat, the less mouthfuls of fattier foods you'll eat," he says.