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One of the best things about summer is biting into a juicy strawberry from the garden. But is
fresh really best? Do frozen fruits and vegetables have more nutritional value? And what about
canned fruits and vegetables—are they actually as bad as we think?
Many people believe fresh is best and canned is worst when it comes to nutritional value of
fruits and vegetables. Truth is, the nutrient content of any raw food depends more on its
genetic makeup, climatic conditions during growth, and maturity at harvest than on commercial
processing. These factors can cause quite a variation in vitamin and mineral content. Carrots,
for example, may vary widely in their carotene content and tomato juice can also vary in
vitamin C content.
It is true that the corn you get from a can is not the same as the corn you pick from the
garden—some nutrients are lost during the canning processing. However, studies have shown
that most of the nutrient losses occur at home, not at the packing plant. The B
vitamins—riboflavin, thiamin, and niacin—are easily lost in cooking water, and
vitamins A, C, and E are depleted with heat or storage in the presence of air.
The large losses that occur at home mean the actual vitamin content of table-ready foods is
roughly the same regardless of the type of processing (or lack of processing) the food goes
through. A steaming bowl of peas placed on the table, for example, will contain 35 to 45
percent of its original vitamin C content regardless of whether it was prepared from fresh
peas (45 percent), frozen peas (40 percent), or canned peas (35 percent).
Although most people do not like preservatives added to their foods, some can actually enhance
the retention of vitamins. Two such preservatives are sulfur dioxide and ascorbic acid. Sulfur
dioxide is added during the dehydration process of making dried fruit to retain a bright color,
but a “side effect” is a greater retention of vitamins A and C. Because these
vitamins are destroyed by prolonged exposure to oxygen, dried fruits are best stored in
airtight containers.
What about canned fruits and vegetables? Surprisingly, they contain as much nutrition as their
fresh or frozen counterparts, according to a study conducted at the University of Illinois.
This study compared the nutritive values of 14 different fresh, canned, and frozen fruits and
vegetables, including 84 varieties and commercial brands.
In most cases, this study found that canned fruits and vegetables were nutritionally equal to
fresh or frozen fruits and vegetables. In some cases, the canned items actually exceeded the
Recommended Daily Intake (RDI) for certain vitamins, as listed on the labels. Here are a few
examples of what they found:
Canned Fruit
- Apricots: The vitamin A content of canned apricots was as good as that of the fresh or
frozen apricots (21 percent of the RDI for vitamin A in a half-cup serving).
- Cherries: One half cup of canned cherries contained the same amount of vitamins A and C
as one cup of fresh cherries—even pie filling. Canned cherries contained more vitamin A
than frozen cherries.
- Peaches: Both fresh and canned peaches contained roughly the same amount of vitamins A
and C. Frozen peaches were higher in vitamin C than fresh or canned because ascorbic acid
was added to maintain color (ascorbic acid is vitamin C).
- Pineapple: Both fresh and canned pineapples are excellent sources of vitamin C, providing
more than 20 percent of its RDI.
Canned Vegetables
- Asparagus: Canned asparagus were nutritionally comparable to fresh-cooked and frozen
asparagus.
- Carrots: Canned carrots are a nutrition powerhouse. They contained at least 100 percent
of the RDI for vitamin A. Fresh-cooked and frozen carrots contained comparable amounts as
well. In this study, some brands contained more than 300 percent of the RDI for vitamin A,
surpassing both the fresh and frozen carrots.
- Spinach: Whether fresh, frozen, or canned, spinach is an excellent source of both
vitamins A and C. The canned variety contained anywhere from 50 to 160 percent of the RDI
for vitamin A, surpassing the amount found in fresh spinach.
Fruits and vegetables are also good sources of “phytochemicals,” substances that
may help fight off cancer cells. Broccoli, cabbage, garlic, grapes, and berries are best known
for their phytochemical content. Other good sources include peppers, tomatoes, and corn.
Fiber, another cancer-preventing substance, is found mostly in the peels of fruits and
vegetables and is not destroyed by any kind of processing.
To maximize your nutrition from fruits and vegetables, follow these simple rules:
- Buy fresh produce when it’s in season.
- Limit peeling—some nutrients and phytochemicals are in the skin.
- Steam, broil, or microwave using minimal amounts of liquid when cooking.
- Avoid storing fresh produce in open air for long periods of time.
- When fresh fruits and veggies aren’t in season, consider
canned.
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