Can it! A case for canned foods

by Lindsay Miller on October 26, 2012

Buy local. Fresh is best. Get your vitamins. Eat your greens. Pass on preservatives. We hear messages all of the time about what to eat and what not to eat. But, in reality, healthful eating is not as simple as knowing “what’s good for you.” The truth is that a whole variety of factors influence our food choices–preference, time, convenience, cost, access, and availability, just to name a few.

Image used under Creative Commons from stevendepolo.

For me, cost is a biggie. As a poor graduate student, I have to be resourceful. I scour Craigslist for paid research participant ads, I buy my gas mid-week in the morning (that’s when it’s cheapest), and I buy a lot of canned foods. Some of my friends and family elicit a patronizing “ohh…” or make a face of disgust when they hear about my cabinet full of cans.  But, I have done my research and found that there is a case to be made for buying and eating canned foods!

A Case for Canned Foods

It is often assumed that canned foods, especially produce, aren’t as nutritionally valuable as fresh produce. However, the difference isn’t as drastic as people may think. According to a review series done by researchers at UC Davis (1), the heating process involved in canning does significantly reduce the nutrient content of canned foods, especially for the more water-soluble and heat-sensitive vitamins, like B and C. But balancing out this effect is that fruits and vegetables are canned at the peak of their ripeness–when they have their highest nutritional value–effectively “capturing” those nutrients and preventing further degradation.

The nutrient content of fresh produce, on the other hand, will degrade over time, and like canned foods, will decline with heating or cooking. The review even concluded that, “by the time a fruit or vegetable is consumed, fresh, frozen, and canned versions may be nutritionally similar, depending on the post-harvest handling and processing treatments.” As the table below shows, some vitamins and foods are more “nutritionally resilient” to the canning process than others.

A summary of some of the data from the UC Davis review.
Notes: Values for canned products are drained, and values are for cooked foods unless denoted with *.

Further, a recent study (2) suggests that canned goods are more nutritionally cost-effective–that is, they give you more nutrient “bang” for your buck. Researchers calculated “total cost per edible portion” by combining product price, the cost of waste, and the cost value of preparation time. Then, they divided that “total cost per edible portion” by the “amount of nutrient available in that portion” for a variety of nutrients, including vitamin A, C, folate, fiber, and protein. They found that “cost-per-nutrient” value, in general, was less for canned foods than for fresh foods.

Wouldn’t want to eat this spoiled fruit…
Image used under Creative Commons by erix!

In addition to being cheap and decently nutritious, canned foods also have a longer shelf-life compared to fresh foods. Unopened canned foods are usually good for 2-4 years after the canning date. Most fresh produce won’t last longer than a month, unless frozen. And eating spoiled fruit and vegetables can lead to some unpleasant consequences, primarily gastrointestinal distress.

 

 


The Cons of Cans…& How to Avoid Them

The use of BPA (bisphenol A) in the lining of canned foods has been a more recent concern, since BPA from the lining seeps into the food product and is then consumed. Exposure to this compound has been linked with a variety of negative health outcomes, including breast cancer, neurologic developmental issues, and reproductive dysfunction. There is still a need for more research examining the effect of canned food consumption on body BPA levels, since existing studies (3) measure urine BPA levels, which may not indicate BPA levels in the body, and also have limited follow-up. While BPA is not currently banned by the FDA for use in bottles and cans, the good news is that many companies–such as Eden’s Organic, Hunt’s, Trader Joe’s, Muir Glen, and Campbell’s–have tuned into the research and started to manufacture (or are planning to manufacture) using BPA-free materials.

One of the main nutritional concerns of canned goods is the traditionally high sodium levels. However, many brands are now offering reduced sodium and sodium-free options. Additionally, draining the canned product can remove much of the sodium content. Other high-sugar syrups and juices can likewise be drained out to reduce this not-so-healthy aspect of canned food items.

A USDA scientist examining a home-canned product with botulism (left).
Image used under Creative Commons from USDAgov

Although very rare, botulism (contamination due to the toxin-producing bacteria Clostridium botulinum) is one of the more serious dangers of canned food items. To avoid this potential health risk, the U.S. Department of Agriculture recommends disposing of cans that are “bulging, leaking, rusting, badly dented” or cans with a foul odor.

Another drawback of canned foods is that they are generally not locally-produced. For those who value eating and buying local, there’s really no getting around this one–it’s an undeniable con of most canned foods.

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Of course, the case for canned foods is strongest if we are to think of health in a holistic way, considering dimensions like financial and emotional well-being. For individuals like myself looking to save money, save time, and maximize the shelf-life of my groceries, buying canned foods can be a reasonable alternative to buying fresh produce. Whether or not buying canned is right for you, well, that’s up to you!

Don’t forget to recycle your cans…or use them to build a train!
Image used under Creative Commons from madmarv00.

 

Sources:

1) Rickman JC, Barret DM, Bruhn CM. (2007). Nutritional comparison of fresh, frozen, and canned fruits and vegetables. Journal of the Science of Food and Agriculture, 87, 930-944 & 1185-1196.

2) Kapica C, Weiss W. (2012). Canned fruit, vegetables, beans, and fish provide nutrients at lower cost compared to fresh, frozen, or dried. Journal of Nutrition and Food Sciences, 2(4).

3) Carwille J et al. (2011). Canned soup consumption and urinary bisphenol A: A randomized crossover trial. Journal of the American Medical Association, 306, 2218-2220.

 

*Post updated 10/29/12*