Spring is finally here! And with it, fresh, locally grown produce is starting to return to farmers markets that have peddled root vegetables all winter. But how do frozen and canned rank? Are they always inferior to the fresh stuff? Let’s break it down.
Fresh, uncooked produce tends to be highest in the nutrients that break down or get leached out with heat (especially water-soluble vitamins, like vitamin C). Many nutrients in produce are also highest at the moment the fruits or vegetables are picked and then start to degrade with time — so if it’s fresh but has been shipped a long distance and takes a week or more to get to the supermarket, it’s probably not bursting with nutrients. The same is true if you buy a picked-that-morning lettuce from your farmers market and then let it sit in your fridge for several days.
Canned produce is cooked as part of the canning process, so it’s often lower in water-soluble vitamins. On the other hand, some vitamins get intensified by cooking — canned peas, for instance, have three times the vitamin A of fresh, uncooked peas. Most canned vegetables have salt added, although you can sometimes find “no salt added” varieties (typically for an upcharge). Canned fruit can be canned in fruit juice or in syrup — syrup adds a lot of extra sugar that’s not good for you.
Frozen produce is frozen soon after picking, so a lot of the nutrients are locked in. And, since it stays frozen until you’re ready to use it, it’s often a better bet nutritionally than those fresh peas you bought last week and meant to use but didn’t. However, the texture is definitely compromised, and so it works better in some dishes than in others — you can’t use frozen spinach in a spinach salad, for instance.
Peas, 1/2 cup:
Fresh, raw: Calories 58, Sodium 7 mg, Fiber 4 g, Protein 4 g, Vitamin A 11%, Vitamin C 48%, Vitamin K 23%
Frozen (then boiled): Calories 62, Sodium 58 mg, Fiber 4 g, Protein 4 g, Vitamin A 34%, Vitamin C 13%, Vitamin K 24%
Canned: Calories 66, Sodium 310 mg, Fiber 4 g, Protein 4 g, Vitamin A 36%, Vitamin C 20%, Vitamin K 26%
Corn, 1 cup:
Fresh, raw: Calories 132, Sodium 23 mg, Fiber 4 g, Protein 5 g, Thiamine 21%, Folate 18%, Vitamin C 17%
Frozen (then boiled): Calories 62, Sodium 58 mg, Fiber 4 g, Protein 4 g, Thiamine 8%, Folate 12%, Vitamin C 15%
Canned (salt added): Calories 133, Sodium 489 mg, Fiber 3 g, Protein 4 g, Thiamine 2%, Folate 18%, Vitamin C 2%
Asparagus, 1 cup:
Fresh, raw: Calories 27, Sodium 3 mg, Fiber 3 g, Protein 3 g, Vitamin A 20%, Vitamin C 13%, Vitamin K 70%, Iron 16%
Frozen (then boiled): Calories 32, Sodium 5 mg, Fiber 3 g, Protein 5 g, Vitamin A 29%, Vitamin C 73%, Vitamin K 180%, Iron 6%
Canned: Calories 46, Sodium 695 mg, Fiber 4 g, Protein 5 g, Vitamin A 40%, Vitamin C 74%, Vitamin K 125%, Iron 25%
* Note: when asparagus is raw, it takes up more volume. The frozen and canned versions are denser, which explains why they’re significantly higher in some nutrients.