How healthy are frozen vegetables?
Frozen vegetables can be a great part of a healthy diet. They give you the same benefits as fresh vegetables, and there are extra advantages.
“Despite what you might have heard, frozen fruits and vegetables contain just as many nutrients as fresh produce, and sometimes more,” says Prof. Tim Spector, ZOE’s scientific co-founder and a professor of epidemiology at King's College London.
Frozen vegetables also have a longer shelf life and tend to offer better value for money. Plus, they’re accessible in and out of season.
Below, we’ll dive into the details, explaining how freezing affects nutrients, how healthy frozen veggies really are, and whether you need to check the labels.
Are frozen vegetables healthy?
Fresh or frozen, vegetables are a key part of a healthy diet.
How does freezing work? After they’re harvested at peak ripeness, most vegetables go through a quick process called blanching, involving a brief dip in boiling water.
Partially cooking the veggies in this way helps maintain quality. It stops enzymes in the vegetables from affecting their flavor, texture, and color.
Blanching also helps remove dirt and germs that may be on the vegetables’ skins.
After blanching, manufacturers immediately freeze the vegetables. This locks in the levels of nutrients.
“Fruits and vegetables have the highest nutritional value when they're freshly picked,” explains Aoife Burns, one of ZOE’s nutrition coaches. “But their nutrients slowly decrease as time passes.”
“Freezing them soon after harvesting helps slow down this nutrient loss, preserving their nutritional content for longer.”
Some people might be put off frozen vegetables because they’re a form of processed food. This may be true, but the processing is typically minimal — and it doesn’t make the veggies less healthy.
Also, frozen vegetables don’t often come with added ingredients. Generally, what you see is what you get. There are some exceptions, and we’ll discuss them later on.
Does freezing vegetables affect their nutrition?
Nutritionally speaking, fresh and frozen veggies are very similar. In fact, studies have found no consistent differences.
One study compared the levels of certain vitamins in fresh and frozen fruits and veggies. When it came to vitamin C, levels were either the same or higher in the frozen produce, compared with the fresh.
Frozen peas, carrots, and spinach had lower levels of beta-carotene, a pigment that the body converts to vitamin A.
Overall, nutrient levels were similar in fresh and frozen green beans and spinach.
Another study looked at the mineral contents of fresh and frozen veggies, including levels of magnesium, zinc, calcium, and iron. Again, the researchers found few differences between the two groups.
Differences in nutrients between fresh and frozen veggies are small — not enough to make one type healthier than the other.
When studies have picked up on small differences, they’ve been specific to certain nutrients and vegetables.
Does thawing or heating affect nutrition?
Thawing frozen veggies doesn’t significantly affect nutrient levels. But it may make your veggies mushy.
There’s little need to thaw — heating them does the job and helps the vegetables keep their shape.
However, whether your veggies are fresh or frozen, your cooking method can affect their nutritional value.
A research review assessed how preparation and cooking changed the nutrient levels in a range of vegetables.
The researchers concluded that in general, steaming was best at keeping nutritional quality. But some methods were better than others at preserving certain nutrients.
For example, oven baking and sautéing onions led to the highest levels of flavonols, a type of polyphenol.
With peas, boiling was best at preserving folate levels.
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How do frozen veggies compare with fresh ones?
In general, you can get the same nutritional benefits from frozen and fresh veggies.
There are times when frozen vegetables may be a better option, like when fresh veggies are out of season.
Many of us live in places without year-round access to locally grown vegetables. And fresh produce can be hard to access for lots of reasons, especially if you’re on a tight budget.
Given their long shelf life and partially prepped state, frozen veggies are generally a more convenient option.
They tend to soften sooner during cooking, too, which can make them especially useful in soups, stews, and casseroles. Fresh vegetables hold their crunch for longer.
In terms of nutrition, there’s little difference between frozen and fresh vegetables.
Opting for frozen veggies can be a more convenient and cost-effective way to make sure you’re eating a wide variety of plants.
Are frozen vegetables better for the environment?
Carbon footprints vary from veggie to veggie.
For example, one study suggested that frozen peas had the lowest carbon footprint, while cauliflower stalks had the highest.
Overall, opting for frozen vegetables may mean less food waste. But it’s also important to consider packaging.
You might have access to fresh veggies with little or no packaging, while frozen vegetables usually come in plastic bags.
To learn more about how your food choices can affect the planet, check out the ZOE Science & Nutrition podcast on the topic.
Additives in frozen veggies to check for
Frozen vegetables sometimes come with added ingredients, such as:
Make sure you check the label before you add to your cart. In general, the fewer the ingredients, the healthier the choice.
Frozen vegetables have a similar nutrition profile to fresh ones. Due to their lower cost, longer shelf life, and year-round accessibility, frozen vegetables can be a great choice.
If you’re buying frozen veggies, make sure to check the labels for added ingredients. And if you have some fresh vegetables that might go to waste, you can always chop and freeze them for later.
Adding frozen veggies to your diet can help increase the diversity of plants in your diet. This is a great way to support the community of bacteria in your gut: your gut microbiome.
If you’re interested in improving your gut health, ZOE could help. Our at-home test measures your gut health and how your blood sugar and blood fat levels change in response to different foods.
With this information, our personalized nutrition program can guide you toward the best foods for you and your health goals.
To learn more about how it works, take our quick, free quiz.
An overview of health-promoting compounds of broccoli (Brassica oleracea var. italica) and the effect of processing. Food Science and Technology International. (2012). https://pubmed.ncbi.nlm.nih.gov/23175779/
A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes. International Journal of Gastronomy and Food Science. (2016). https://www.sciencedirect.com/science/article/pii/S1878450X15000207
Determination of carbon footprint in the processing of frozen vegetables using an online energy measurement system. Journal of Food Engineering. (2022). https://www.sciencedirect.com/science/article/abs/pii/S0260877422000280
Effect of different cooking methods on the content of vitamins and true retention in selected vegetables. Food Science and Biotechnology. (2017). https://link.springer.com/article/10.1007/s10068-017-0281-1
Effect of industrial freezing on the physical and nutritional quality traits in broccoli. Food Science and Technology International. (2018). https://journals.sagepub.com/doi/full/10.1177/1082013218795807
Evaluation of different cooking conditions on broccoli (Brassica oleracea var. italica) to improve the nutritional value and consumer acceptance. Plant Foods for Human Nutrition. (2014). https://pubmed.ncbi.nlm.nih.gov/24853375/
Freezing. (2014). https://nchfp.uga.edu/how/freeze/blanching.html
Impact of the industrial freezing process on selected vegetables — part II. Colour and bioactive compounds. Food Research International. (2015). https://pubmed.ncbi.nlm.nih.gov/28454976/
Mineral, fiber, and total phenolic retention in eight fruits and vegetables: A comparison of refrigerated and frozen storage. Journal of Agricultural and Food Chemistry. (2015). https://pubmed.ncbi.nlm.nih.gov/25525668/
The effect of food preparation on the bioavailability of carotenoids from carrots using intrinsic labelling. British Journal of Nutrition. (2012). https://pubmed.ncbi.nlm.nih.gov/21923982/
Vitamin retention in eight fruits and vegetables: A comparison of refrigerated and frozen storage. Journal of Agricultural and Food Chemistry. (2015). https://pubmed.ncbi.nlm.nih.gov/25526594/