For years, nutritionists and health experts have stressed that we should shop the perimeter of supermarkets or at local farmers' markets. But the middle rows—the aisles with canned fruits and vegetables—are finally getting their due. As it turns out, buying produce off the shelf isn't bad at all: The canned stuff can be just as healthful as its fresh counterparts—sometimes even more so.
Studies have found that produce is most nutritious within hours of harvesting. And because most of us get our fruits and vegetables days later (whether from supermarkets or even farmers' markets), we're not eating them at their peak. That's why canned and frozen goods make more sense. According to a paper by researchers at the University of California, Davis: "Fresh fruits and vegetables usually lose nutrients more rapidly than canned or frozen products."
For example, vitamin C is easily lost over time, especially if the produce is held in a warm environment. "Even under refrigeration, up to 70 percent of the vitamin C is lost in green beans and spinach after one week of storage," says Christine M. Bruhn, one of the paper's authors.
Of course, canned produce can suffer from degradation, as well—especially when it comes to water-soluble nutrients like vitamins B and C. But canned fruits and vegetables don't get exposed to the deteriorating effects of oxygen. Fat-soluble nutrients (including carotenoids, vitamin A, and vitamin E) are typically higher in canned goods—partially because they undergo a mild heat treatment during the canning process. Plus, the produce is picked and processed at its peak, so while there is a loss of some vitamins, the majority of the nutrients make their way into the can.
"With some products, such as tomatoes, nutrients can be higher in the canned compared to the fresh product," Bruhn says.
Indeed, canned tomatoes and tomato paste have been proven to have greater levels of lycopene (believed to protect against heart disease and some cancers) than fresh tomatoes. And the American Dietetic Association says that other vegetables, like canned corn and carrots, also provide higher amounts of some antioxidants than their fresh counterparts.
Another plus on the canned-goods side? Not that you're pinching pennies, but canned produce also provides more nutritional bang for your buck. A February 2014 Michigan State University study looked at more than 40 studies in scientific journals and compared canned fruits and vegetables to fresh and frozen. The canned options had similar nutrition scores but cost less per cup than either frozen or fresh. For example, one cup of canned spinach costs $0.84, and the same amount of fresh sets you back $3.92. Canned green beans cost $0.67, while the fresh version hits $3.23. (Full disclosure: The study was commissioned by the Can Manufacturers Institute, but the science was legit. Experts looked at eight common vegetables and 10 fruits across all forms of packaging. They calculated the nutrients per calorie and got the average costs from the U.S. Department of Agriculture's Economic Research Service.)
According to a 2010 study published in the Journal of the American Dietetic Association, all canned, frozen, and dried fruits contribute less than 2 percent of the added sugar in most Americans' diets, and vegetables add less than one percent of the sodium. Eating more canned produce could increase those numbers, but there are simple fixes: Look for low-sodium vegetables or rinse them before cooking (this significantly reduces the trace of sodium) and drain the juice from canned fruit. While you're at it, look for labels that say no artificial flavors and no artificial preservatives (although because the food is in a sealed, airtight container, chemical preservatives are rarely required these days).
None of this is to say that you should eat strictly out of cans with a pop-top lid, though. Leading experts always suggest a varied diet—including a mix of fresh, frozen, and canned produce. And let's not even get into the moral and political implications of snubbing your local farmers.