Ask Adam: Fresh, Frozen, or Canned?

Posted by Adam - 08/11/08 at 02:08:14 pm

As this is my first post, I would like to introduce myself somewhat. I am currently enrolled in North Carolina State University, double majoring in Nutrition and Food Science and Biology. Food, health, and nutrition has always been a passion of mine and Gyminee has wonderfully granted me the ability to post on their blogs, and in turn I would like to include the Gyminee community in my posts. Every week I will take either a submitted question or a question from the Gyminee forums and post a response. To submit a question simply email me. This weeks Ask Adam post I am taking from the topic “Frozen vegetables & fruit.”

Are frozen vegetables as healthy as non-frozen?

One of the most talked about topics in nutrition is that of fresh foods vs. pre-packaged foods in regards to nutritional value. While much goes into this topic, I will briefly cover the three most popular choices of produce: Fresh, Frozen, and Canned (I will not cover dried foods). Before I dive right in I need to back up and mention a few basic facts about nutrients. The first important lesson you need to know is that nutrients can be “destroyed” (a change in their chemical characteristics) or “lost” (removed from the food but not changed chemically) from food for various reasons. Nutrients can be “destroyed” as a result of:

• Exposure to air (oxygen)
• Exposure to heat
• Exposure to light (sunlight or artificial)

Nutrients can also be “lost” as a result of:

• Exposure to water

The amount of nutrients that are destroyed or lost depends on several things:

• The length of time of the exposure (more time= greater destruction/loss)
• The temperature (higher heat= greater destruction/loss)
• The amount of the water (more water= greater destruction/loss)
• The amount of the food’s surface area that is exposed (smaller pieces= greater destruction/loss)

Fresh

Fresh foods are generally the choice of many. Over the years people have been led to believe that you have to have FRESH fruits and vegetables to get the full benefits of their nutrients. However, the “fresh” fruits and veggies you buy at the grocery store or fresh market usually have traveled quite some distance to get there. Also, many grocery stores are open 24/7, so they may encounter 24 hour light for several days before being purchased. And lastly, IF they are pre-cut and unpackaged, the exposure to air and light is very high.

Frozen Food

Many people who shy away from frozen foods do so because of “loss of taste.” In terms of nutritional content though a couple things must be taken into consideration. Firstly, foods that are frozen are usually picked at their peak maturity when the nutrient content is likewise to be at its peak. Also, most fruits and vegetables are “flash frozen” which has nearly negligible effect on nutrient content. Keep in mind that as long as frozen foods are kept frozen, their nutrient levels remain stable.

Canned Food

Canning food is an interesting process. Canning involves heating foods to a very high temperature for a very short period of time to kill off any microorganisms. Because the time exposure to heat is so small, the nutrient destruction is very low. While preservatives are used, most of the time the amount is minimal as there is little need due to the flash heating. Also note that most canned food sits in water, so water soluble vitamins (the B’s and vitamin C) and various other minerals will actually leach out into the water of the can. Fortunatly, these “lost” vitamins and minerals can be “recaptured” by simply consuming the liquid.

Conclusion

Research has proven that “fresh” fruits and vegetables actually contain significantly less heat and light liable nutrients than frozen or canned foods. Other than this, the nutritional content is remarkably the same. Canned and frozen foods should not be identified as less healthy than fresh foods when the opposite is true and in canned foods there is actually some evidence that suggests phytochemicals in the carotenoid family (like beta-carotene, lycopene, and lutein) are made more available through the heating process.  For those of you who wish to find alternative choices with less preservatives, seek out your local farmers market and find the foods that were picked the most recent and ask them about their pesticide practices.

While this has been a brief overview of the topic, the choice is yours and my advice is to eat what you feel comfortable and what you find reasonable. Compare the nutritional information on the label of products with the USDA choice in the Gyminee database and see what adds up. Researching your own foods and knowing what you are eating is a great way to stay healthy!

Fun Nutrition Fact of The Week:
Everyone likes waffles right? But did you know that waffles have been around for thousands of years? The first waffles were cooked between two very hot metal plates by the ancient greeks. They were called obleios, and later called oublies in the middle ages. The word waffle originally comes from the Dutch version in the mid 1600s from the American Pilgrims who lived in Holland before coming to America. Waffle parties were very popular in the 18th century and Thomas Jefferson brought the first waffle iron to American from France. It was not until a century later that maply syrup became popular on waffles sold on street corners. In 1953 the first frozen waffle began being sold, the Eggo Waffle. 1964’s World Fair introduced the “Belgian Waffle” to the world, which were fatter and thicker. The rest, is history.

Have a question about food or nutrition? Send Adam an email for the Ask Adam series on Gyminee Blog.

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