As a dietitian, I often get asked if frozen vegetables are as good as the fresh varieties. When it comes to the fresh vs. frozen veggie debate, I see a place in a healthy diet for both. If I were to compare the two, fresh vegetables would be the winner with respect to texture. The crunch of fresh veggies certainly cannot be replaced with that of frozen vegetables. And the sheer variety of fresh vegetables compared to that of what is in the frozen food aisle makes them slightly better in that respect. Nutritionally, however, it a different story.
Many wrongly believe that frozen vegetables are a poor substitute for their fresh counterparts. This isn’t always the case. Frozen vegetables are, surprising, not the nutritional underdog. When compared to fresh vegetables, frozen veggies are at times nutritionally superior depending on the nutrient in question. In some vegetables, the vitamin C and beta carotene (a vitamin A precursor) content has been found to be superior when frozen veggies are compared to fresh, refrigerated ones.
While canned veggies lose significant amounts of nutrients during the canning process, the freezing process keeps many nutrients intact. Frozen veggies are picked at peak ripeness and are quickly frozen, preserving their nutrients. Fresh veggies are most often pick before they are fully ripe so that they can make it to the supermarket before going bad. Of course, fresh veggies from your garden or local farms won’t have this problem.
So why does ripeness at time of harvesting matter? Well, for the majority of fruits and vegetables nutrients are most abundant and available when the plant is at peak ripeness. And because fresh veggies have to travel longer in their unprocessed and unpreserved state, they will lose more nutrients than the frozen ones on the way to your table.
Studies show that spinach and green beans can lose up to 75% of their vitamin C content after 7 days and peas can lose up to 25% of their vitamin C in a mere 24 hours after harvesting. Freezing can help retain nutrients, if done quickly. In fact, 70% the beta carotene content can be retained in some vegetables when taken straight from farm to freezing.
Now not all nutrients benefit from the freezing process. The brassica family of vegetables (e.g. broccoli, cauliflower, and cabbages), for example, retain more health promoting antioxidants and phytochemicals in their fresh, rather than, frozen state. It seems that the chemical properties of some nutrients fair better in the freezing process than others. And within the same vegetable, some nutrients can be retained closer to their original state while others, cannot.
Nutritionally speaking, both fresh and frozen vegetables are sound options. Vegetables are going to lose some nutrition whether they are frozen or fresh. Remember, just because they have lost a certain percentage of their nutrients, it doesn’t mean that they are devoid of nutrients altogether. If you are eating a variety veggies each day, you’ll likely be meeting or exceeding your daily micronutrient needs whether your veggies are fresh or frozen.
Frozen vegetables score well on the convenience factor. I'm willing to bet that they've also saved a number of meals when time is running short or when all the fresh veggies have gone unexpectedly bad. I think it’s great to have a small supply of frozen veggies around for such occasions. Frozen vegetables are great for adding to soups, curries, or pasta sauces. They are sodium free, unlike their canned counterparts, and for the most part are preservative free (some frozen mushrooms are treated with a phosphate-based preservative). Really, my only concern with someone who chooses frozen vegetables all the time is lack of variety. A limited variety of vegetables means that you are limiting your ability to obtain a greater spectrum of nutrients. So, including a variety of vegetables, fresh and frozen, in your dietary rotation is probably the best thing you can do for you health and palate.