Can The Can Deliver The Goods?
Americans prefer their green beans, sweet corn, pineapple and kale from a can, according to a consumer report published by the USDA in 2004.
(See data evaluation at end of story)
While the U.S. National Library of Medicine and the National Institute of Health say that canned and frozen fruits and vegetables are an acceptable nutritional alternative, second to frozen and fresh, some studies show that the canning process may decrease nutritional value by up to 60 percent. When fresh fruits and vegetables often cost more, it’s easy to understand why some are choosing the less healthy way to eat some of their veggies.
Though some people would never even consider bringing a can of green beans home. “We don’t do can,” said Stephanie Lang, a single mother and full time student at UNR. “It’s just wrong.”
- Though canned fruits and vegetables aren’t as nutritional as their fresh or frozen alternatives, they can still be a good source of fiber, carbohydrates, and protein.
Some people, on the other hand prefer canned veggies, and for reasons other than their economic restrictions.
“Canned green beans are sometimes the perfect compliment to a meal. Fresh green beans are too crunchy,” said Devin Seidel, a University of Nevada Reno psychology major.
Whatever the reason may be, Americans are not only getting a lower density of nutrients, they aren’t even coming close to their daily recommended requirements. According to “Nutrition and Your Health: Dietary Guidelines for Americans,” published by the USDA, 5-13 daily servings of fruits and vegetables can help reduce the risk of stroke, cardiovascular diseases, some cancers, diabetes, and can be a helpful component in fighting obesity.
National studies say that Americans are only eating a meager 3.2 servings of fruits and vegetables a day on average. When those 3.2 servings may be coming from food that is lacking in nutrients, there may be reason for concern.
Produce that is processed for canning is heated to temperatures up to 140 degrees, which changes the nutritional composition of the produce. Frozen fruits and veggies aren’t heated at such high of temperatures, so maintain more nutrients.
According to a study on the effects of freezing and canning produce published in 2007 by the Journal of The Science of Food and Agriculture, consistent observations were difficult to achieve. Certain nutrients, such as vitamin A responded differently to the canning process, depending on time of harvest, time in shipment, type of vegetable, and what the processing plant’s regulations were.
What was evident in the data, however, was that the whole nutritional “snapshot” of the selected produce was altered to a much greater degree in canned food than in frozen food.
According to Dr. Karen Spears, UNR assistant professor, nutrition state specialist, cooperative extension agent and registered dietitian, some water soluble vitamins, such as vitamin C are more susceptible to heat and oxidative damage.
Dr. Spears talks about nutrition, canned, frozen and fresh produce, and gives recommendations:
In a summary published by University of California-Davis on the nutritional comparison of fresh, frozen, and canned fruits and vegetables, 10 to 90 percent of vitamin C can be lost during the canning process. Other nutrients such as vitamins E, A, B6 and more are also affected.
But canned veggies are not all bad. The same study found that while the canning process can deplete nutrients, once canned there is no further loss of nutrients. Meanwhile, frozen vegetables can lose nutrition in storage. Canned vegetable also maintain their original levels of protein, carbohydrates and fatty acids, and the heating process can often make some nutrients more “available” to our bodies.
The study concluded that “exclusive recommendations of fresh produce ignore the nutrient benefits of canned and frozen products and limits consumer choice.” This suggests that people might benefit from more options and a variety of different sources of vegetables.
Frozen fruits and vegetables are considered a second-best choice, as they are typically picked fresh, and frozen right away.
But fresh is recommended above all other options by the USDA, nutritionists, and scores of publications. Not only fresh, but as fresh as possible. Spears said that as much as 77 percent of vitamin C can be lost in a week of fresh produce shipment and storage.
Not only are well-known nutrients such as vitamin C sensitive to oxidative damage, so are nutrients known as phenolics. One group, know as polyphenols, Spears said, are the compounds responsible for a fruit or vegetable’s color. These compounds, as well as many others help to protect the plant, and therefore are believed to protect our bodies. Many of these compounds are better known as antioxidants.
Fresh vegetables might not always be more promising. According to the same consumer study published by the USDA in 2004, many of the fruits and vegetables considered were noticeably more expensive fresh.
Spears suggested though that newer studies have found fresh produce is not always pricier. In-season products can save considerably.
“If you’re going to look at nutrition as a whole, buying from your local produce, and having the least amount of time from picking to consumption is going to be your best option,” Spears said.
DATA EVALUATION
(To review the data, visit: www.ers.usda.gov/data/fruitvegetablecosts/)
