Canned foods — which first appeared in the 19th century — offer the convenience and variety of foods that can be easily prepared. Heat processing ensures the quality of canned foods — and with the growth of the industry in recent decades, not only can you find canned fruits and vegetables, but you may also find gourmet foods such as lump crab meat and escargot. Canned foods offer some nutritional benefits, but they can also be high in sodium.
One concern you may have with canned foods may lie with their nutritional value. These foods may have undergone some type of processing before you purchase them at the grocery store. Research published in 2008 in the "Journal of Agricultural and Food Chemistry" reported that neither boiling, steaming nor frying lowered the antioxidant or phytonutrient content of carrots, zucchini, or broccoli, though cooking did alter the physical characteristics of each of the foods. Researchers found that, surprisingly, cooking increased the antioxidant capacities of each of the foods, which they attributed to chemical changes caused by cooking.
While you may not be sacrificing nutrition, canned foods can be prohibitively high in sodium. The U.S. Department of Agriculture's 2010 Dietary Guidelines for Americans warns that Americans consume far too much salt, the majority of which comes from processed foods. Sodium is often used to preserve the quality of canned foods. Yet, a diet high in sodium can increase your risk of developing high blood pressure. Sodium causes your body to retain water, which, in turn, increases your total blood volume. The greater the volume, the harder the heart muscle must work to maintain blood flow. The pressure in your blood vessels will consequently increase.
Eating canned foods does offer some health advantages. They're widely available, which allows you to incorporate veggies into your diet even if you don't have access to fresh produce, or fresh fruits and veggies are too expensive. You can easily incorporate many kinds of fruits and vegetable in your diet, some of which might be out of season or not otherwise available in your area. Increasing intake of these two foods groups is one of the key recommendations of the Dietary Guidelines for Americans.
Improving Nutritional Value
You can improve the health value of canned foods by choosing fat-free or low-sodium offerings. Rinsing canned beans, for example, before cooking will remove some of the salt content. Look out for added sugar in canned fruit -- look for varieties canned in water or juice, instead of in syrup. You should also use canned foods prior to the expiration date for best quality.