Back when I was in college, the hardest part of eating healthy was ensuring access to lots of fruits and veggies. Ideally, of course, we’d have our own garden or access to a farmers’ market. The problem is that fresh veggies don’t keep very well for long periods of time, so I would prefer to buy them in smaller quantities to avoid wasting money. But then, I would have to go grocery shopping for produce much more frequently than for other items. The solution: buy some vegetables frozen or canned. They keep longer, so they are easier to work into a busy schedule, and in some cases are more convenient, helping you save time in preparation. But what about the relative health impacts?
The Truth about Fresh and Frozen
The general consensus is that fresh vegetables are preferable, but only when they are in season. Out of season, they must be shipped long distances from where they are in season, and so they are often picked before they are ripe. The result is that they don’t have the opportunity to develop their full nutritional profile, even if they are outwardly ripe when you pick them up. Tomatoes are a prime example of this. They are picked when green and then exposed to ethylene gas so that they turn red without actually developing the nutritional profile of a ripe tomato.
Freezing is generally thought to be the next best thing to in-season, locally grown vegetables. This is because most frozen vegetables are quickly flash frozen at the point of harvest, when the vegetable is at peak ripeness. Because most nutrients can survive freezing, this ensures a pretty high nutrient content. The only caveat is that frozen vegetables are quickly blanched with steam just before freezing, to kill any bacteria on the surface, which can harm some fragile phytonutrients.
Canned vegetables are basically cooked before canning. The process involved in canning pretty much eliminates most of the nutrient content of canned vegetables. Notable exceptions include tomatoes, which according to Sally Fallon’s book, Nourishing Traditions, contain carotins which are resistant to heating. They still lose most of their vitamin C content, however.
From a nutritive standpoint, I recommend doing your best to get fresh fruits and vegetables in season, and locally if possible. For most of us, this means no fresh tomatoes in the dead of winter, no parsnips in July. For the rest of the year, or if you just have to have berries in December, go for frozen. Unless you have the time and space to can and preserve your own fresh veggies from when they were in season, frozen vegetables are a pretty good alternative. I would still get some fresh vegetables, even if they are out of season in your area, just to have some access to those delicate nutrients (and because sometimes you just need a fresh crisp cucumber). Save canned veggies for tomato sauce and pumpkin pie.
Convenience
As far as convenience goes, frozen wins out for sure. Most grocery stores sell frozen bags of mixed, pre-cut veggies. Trader Joe’s is awesome for this, as they have several varieties of pre-mixed veggies, from stir-fries to peas and carrots (I’d argue that Trader Joe’s has a better selection of frozen compared to fresh produce). All you have to do is pour some out into a skillet with some oil or butter, sautee until tender, and you’re done! Just freeze the leftovers in the bag. This definitely beats washing, peeling, and dicing fresh vegetables every time you want to cook something up, and I can’t recount the number of times I was so tired from a hard day at the library that the only reason I even ate veggies was because it only took a couple minutes to thaw some frozen Asian stir-fry mix. Certainly a salad would have been preferable but we do what we can.
Here are some resources if you’d like to do your own research:
Medline, the National Institute of Health
The Weston Price Foundation, no specific articles, but search frozen vegetables and there’s plenty to read
Nice article. If it weren’t for frozen veggies, I don’t think my family would eat nearly enough. I was skeptical of frozen fruit and vegetables for a while, but recently I’ve started freezing my own; I’ll buy a bunch of what’s cheap and in season, keep some out fresh, and then freeze the rest for later. This would be easier with an extra freezer, but like you said, you do what you can. People argue that it’s not convenient to eat healthfully, but it’s nice to be able to just open my freezer, toss some fruit and greens into the blender, and have a raw protein shake in 5 minutes.
By: Anna on February 3, 2010
at 1:13 am