Hi friends! How are you all doing? I finally got groceries yesterday after over two weeks of making do with what I had on hand. I was so excited to dive into my fresh salad last night, as I’d been eating frozen and canned produce the few days prior (which I recognize, all of this is still a large privilege).
As I’ve been relying more on frozen and canned produce lately, I thought I’d dive into the nutrition science of shelf-stable fruits and veg in a blog post. So, are frozen and canned fruits and vegetables nutritious? Let’s dive into what the science says so far!
Is frozen food nutritious?
Well, it depends. Most of us probably know that a pint of Ben & Jerry’s and a package of no-salt-added frozen green beans represent two vastly different nutrient profiles.
For the purpose of this post, we’ll focus primarily on frozen produce (perhaps I could do a different post about frozen entrees).
Okay, so are frozen fruits and vegetables nutritious?
Practically speaking, having frozen fruits and vegetables on hand can be an affordable and nutritious way to add produce to your diet. And it seems as if opening your dietary repertoire to frozen produce may increase your intake.
A 2018 study found that, on average, people who consume frozen fruits and vegetables eat significantly more total servings of fruits and vegetables compared to people who don’t consume frozen fruits and vegetables.
The study also found that frozen fruit and vegetable consumers got more fiber, calcium, and vitamin D compared to non-frozen fruit and vegetable consumers, and consumed less energy (calories) overall.
The authors of the study concluded that frozen fruits and vegetables can fill the fruit and vegetable gap to help Americans meet their recommended produce intake in a way that other forms, like dried, canned, and fresh fruits and vegetables do not.
Now, does this mean that buying frozen fruits and vegetables will make you healthier? Not necessarily, as there may be many other factors associated with the kinds of people who buy frozen vegetables and fruits (perhaps more health conscious) compared to those who don’t that could partially explain these results.
That said, it does suggest that embracing frozen produce might encourage you to eat more of it. And given that frozen fruits and vegetables are often more affordable and last longer than fresh, it can be a wise addition to a balanced diet.
Anecdotally, I used to kind of be opposed to frozen vegetables. In my mind, they were gross (I think I was remembering mushy unseasoned ones of the 90s in cafeterias). But once I discovered how much they’ve improved in recent years (I find Trader Joe’s, Aldi, Whole Foods, Green Giant, and Cascadian Farms brands to have darn decent frozen produce compared to some of the others), I became a big fan and now eat a lot of frozen veggies.
Now, let’s talk nutrition in terms of the fruits and vegetables themselves. What impact, if any, does freezing have on the nutritional integrity of the produce?
And, generally speaking, freezing fruits and vegetables results in pretty good retention of vitamins and minerals, meaning for the most part, they are just as nutritious as fresh fruits and vegetables.
In some cases, they may even have more of certain vitamins and minerals compared to fresh produce, especially if it has been sitting out on the counter or in the refrigerator for long periods of time.
Many think this may be because frozen vegetables are often picked and processed at peak freshness, whereas regular produce is often picked before it is ripe, and then is allowed to ripen over time.
Not all fruits and vegetables have been tested to measure impacts of freezing on nutrient profiles, but the existing data suggests most kinds of produce most of their micronutrient and antioxidant profiles.
One study that compared levels of vitamin C, riboflavin (a B vitamin) and forms of vitamins E and β-carotene (a precursor of vitamin A), in corn, carrots, broccoli, spinach, peas, green beans, strawberries, and blueberries, found that vitamin C was not significantly different for 5 of the 8 kinds of produce; the 3 types of produce that did have differences between fresh and frozen actually found higher vitamin C content in the frozen varieties.
Riboflavin was roughly the same in fresh versus frozen corn, carrots, spinach, green beans, strawberries, and blueberries, but was higher in frozen versus fresh broccoli, and lower in frozen versus fresh peas.
Vitamin E was the same in most varieties of fresh versus frozen produce sampled; if anything, it was found in higher levels in frozen vegetables. A few kinds of vegetables — namely peas, carrots, and spinach — had less β-carotene in their frozen compared to fresh forms, but the rest were similar.
What about healthful plant compounds, like antioxidants? Again, it seems like for the most part, freezing maintains their integrity, with some antioxidants seemingly losing activity due to freezing, and others seemingly being enhanced by it.
Now, it’s worth noting that with all of these studies, the various impacts of freezing on vitamin, mineral, and antioxidant contents may present slightly differently in different studies due to different experimental methods, conditions, and differences in chemical structures of the different micronutrients and plant compounds.
But more or less, the take home is this: the nutritional content of frozen fruits and vegetables doesn’t differ significantly when compared to fresh, and when it does, it seems that there are actually more benefits than detriments to the nutritional quality of the food.
Even if minor enhancements and losses occur due to the freezing process, when eaten as part of a diverse, nutritious diet – these tiny differences really doesn’t matter much.
What matters more is simply getting multiple servings of fruits and vegetables every day (when possible, I recognize that this is a privilege and access and economics may impede some people from obtaining any at all).
Tips for selecting and storing frozen produce:
Buy fruits and vegetables you like to cook with, since typically, frozen produce translates best when cooked (ie, thawing frozen broccoli to dip in hummus as you would fresh broccoli will not likely yield the same satisfaction as say, cooking frozen broccoli into a stir-fry).
If you are watching your intakes of salt or added sugars, scan ingredient lists to see if the product has any added salt or sauces that may be packed with sugar and sodium.
If these are things you are trying to reduce, opt for produce that only contains frozen produce, and does not have any additional ingredients, like added salts, sugars, etc. You can add seasonings and spices at home to enhance their flavors.
Of course, if you are not avoiding salt and sugar and want to try various frozen vegetable products that come with sauces or seasoning, I don’t see the harm in enjoying oneself and having fun with fruits and vegetables. Just be aware of what you’re consuming, and see it for what it is (ie, when I eat Kung Pow Cauliflower from Trader Joe’s, which is breaded, fried, and covered with a delicious sweet sticky sauce…I know it’s not the same as steamed plain cauliflower rice).
If you use only part of package of frozen produce, consider transferring the remaining portion to an air-tight container to avoid freezer burn.
Should freezer burn occur, you can scrape it off, run the produce under hot water, and cook as usual. Freezer burn is a matter of quality, not safety, meaning that eating freezer burned food is totally safe, it just may have an altered flavor or texture.
What about canned produce?
Canned produce, much like frozen produce, is often picked and processed at peak freshness.
That said, because canning requires high-heat processing, some canned goods may have less water-soluble vitamins, like B vitamins and vitamin C. It also seems as though certain bioactive plant compounds may partially deteriorate at high heat.
On the other hand, the heating process also increases the content of certain antioxidants. Canned tomato products, for example, have higher levels of lycopene (an antioxidant) than do fresh tomatoes.
Tips for selecting and storing canned produce:
When working with canned produce, it may be worthwhile to check the product’s sodium content. Many canned vegetables and legumes are processed with a hefty dose of salt, a mineral that 90% of Americans over the age of 2 consume too much of.
If you must limit your sodium intake for health reasons (which may apply to certain people undergoing medical treatments for their thyroid who must avoid iodine, and/or people with high blood pressure that are renin-sensitive), aim to select reduced sodium and no-salt-added versions of canned produce.
For others looking to reduce the amount of salt consumed in the diet, draining and rinsing the canned produce can help decrease the salt content.
And if you’re enjoying some canned fruit, be sure to check out the added sugar content. Many canned fruits (like peaches and pears) are packed in ‘light’ or ‘heavy’ syrup, which is essentially a bunch of liquified added sugar. If consuming excess added sugars is a concern for you, strive to select fruits packed in water or 100% juice, and/or drain and rinse the syrup.
If possible, select BPA-free canned foods over the alternative. BPA is a compound I could easily devote a whole post to, but long story short, it is a chemical compound found in some plastics that may be an endocrine disruptor.
It has been shown to alter reproductive health in animal studies, and human studies suggest in utero exposure (meaning, exposure to an infant in the womb via their mother) to BPA may increase risks of certain neurological outcomes, including increased risk of anxiety and depression.
And lastly, a food safety concern for canned produce: avoid buying or eating any canned foods that have bulges, cracks, or dents, as these can be signs that the food may be contaminated with botulism, which is a potentially-deadly toxin.
Be extra vigilant about home-canned products, as they are at even higher risk for developing botulism if not processed properly. If you are a home-canner and want to learn about reducing this risk, see the USDA’s guide to Home Canning and Botulism.
What about freezing fresh vegetables I don’t think I’ll use before they go bad?
Freezing certain vegetables and fruits that you don’t think you’ll consume before they go bad is a great way to reduce food waste.
I can tell you anecdotally, that I do this often, and that for certain fresh fruits and vegetables, it works pretty well in terms of maintaining quality and taste, assuming you cook them before eating.
In my experience vegetables like broccoli, cauliflower, carrots, snap peas, onions, cubed potatoes and squash, freeze and reheat really well. Greens like spinach and kale also freeze well, and can be sautéed, or added to soups or smoothies; that said, high-water greens like romaine don’t freeze and reheat well for consumption in typical mediums like salad.
Certain fruits, berries and bananas, also freeze quite well. Frozen bananas work well in smoothies and baked goods, and frozen berries reheat well and can be eaten as a compte-of-sorts on top of oatmeal, toast, or pancakes, or make delicious chia jam. Even avocado, when sliced and frozen, holds up better than in the freezer than you might think.
But what happens to the nutritional integrity of foods you take from fresh and freeze at home?
There haven’t been too many studies done on this topic, but one study from 2019 did examine the impact of heating and freezing on antioxidant profiles in garlic, onion, broccoli and cauliflower.
The study found that at-home freezing decreased antioxidant activity of cauliflower and onion, but improved antioxidant activity of broccoli and garlic.
Overall, it seems that freezing vegetables as opposed to letting them sit in the refrigerator maintains most of the micronutrients, and even improves the integrity of some.
It seems that once again, freezing, like all processing methods, may have some impacts on produce, but when eaten as part of a robust balanced diet, does not seem to be something to worry too much about.
Take home: Are frozen and canned fruits and vegetables nutritious?
Frozen and canned fruits and vegetables are affordable, shelf-stable, and nutritious. While freezing and canning produce may impact the levels of some vitamins, minerals, and antioxidants, the differences are most often minor, and in some cases, these processing methods may enhance levels of some of these healthful compounds.
What matters less than these small differences in micronutrient and antioxidant content is eating a diverse, robust diet, and getting multiple servings of fruits and vegetables every day (when possible, I recognize that this is a privilege; physical and economical access is not equal across the US and beyond).
But to answer the question: ‘Are frozen and canned fruits and vegetables nutritious?’ it seems the answer is indeed, yes.
And of course, if you are aiming to reduce sodium and added sugar intake, read ingredient lists while shopping, and strive to select frozen fruits and vegetables without added salt and sugar (syrup) most of the time.
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