Study Confirms Canned Foods Packed With Nutrition
Results of a new nutrition study show that, more than ever, dietitians, nutritionists and food service professionals can feel confident recommending delicious, healthy meals prepared with canned ingredients.
Canned foods used in recipes certainly taste good – and they’ve cornered the market on convenience. Yet there is a misperception, even among health professionals, that canned products don’t stack up nutritionally.
In 1995, the University of Illinois Department of Food Science and Human Nutrition released a comparative analysis of a variety of canned, fresh and frozen fruits and vegetables that let a little-known secret out of the can – canned fruits and vegetables are as nutritious as their fresh and frozen counterparts.
In response to queries from health professionals and the media, the University of Illinois has expanded and updated this study in 1997. The new study, called the Nutrient Conservation In Canned, Frozen and Fresh Foods, provides nutritional analyses of about 35 canned fruits and vegetables, as well as poultry and fish.
The new study not only confirms that canned foods are nutritionally comparable to fresh or frozen, but also provides fresh insights into the valuable role canned foods play in the North American diet.
The objective of the study, conducted on behalf of the Steel Packaging Council, was to compare the available nutritional information of canned, fresh and frozen products, both as individual products and as ingredients in five popular recipes.
The information presented came from the United States Department of Agriculture (USDA) nutrient data bank and data gathered from labels provided by manufacturers, based on the latest nutrition labeling regulations from the Food and Drug Administration (FDA). The updated study also includes an analysis of vital nutrients not included in the first study – such as folate, potassium and fiber values for all products, as well as thiamin for the legumes.
Fruits: applesauce, apricots, blackberries, blueberries, grapefruit, Mandarin oranges, peaches, pears, pineapple, purple plums, strawberries, sweet Bing cherries, tomatoes (stewed and whole) and ripe olives
Vegetables: asparagus, beets, carrots, corn, green beans, mushrooms, peas, pumpkin, spinach, sweet potatoes and white potatoes
Beans: black, black-eyed peas, garbanzo, navy, pinto, red kidney and white kidney
Poultry and Fish: breast of chicken, chunk light tuna and pink salmon
Recipe Analysis: Chili, Peach Cobbler, Pineapple Upside-Down Cake, Spaghetti Sauce and Tomato Vegetable Soup
Food Components and Nutrients Measured
The foods compared in this study were analyzed based on two sets of dietary standards: Daily Reference Values (DRVs) and the Reference Daily Intakes (RDIs), as established by the FDA under the Nutritional Labeling and Education Act.
Food Components Measured: (based on a 2,000 calorie diet)
Nutrients Measured: (based on a 2,000 calorie diet)
How Canned Foods Compare
Many canned fruits and vegetables are high in vitamin A, which is essential for the activity of mucus-forming cells in the body, as well as for night and color vision. Since little of the vitamin is lost during the canning process, canned products have similar levels of vitamin A to their fresh and frozen counterparts.
Vitamin A is present in many fruits and vegetables as carotenes – antioxidants that provide protection for the body’s cells. Apricots, carrots, peaches, pumpkin, spinach and sweet potatoes all are high in carotenes.
Tomatoes, in particular, contain an important carotenoid called lycopene, which appears to be effective in preventing certain cancers. In fact, some analyses show lycopene is more effective when it is consumed after it is heated or canned.
Many fruits and vegetables are important sources of dietary fiber. Blackberries, blueberries, cherries and strawberries, as well as apples, carrots, beans and peas, provide this vital food component in the form of cellulose and pectins. The canning process does not affect fiber content, making them comparable to fresh and frozen. In fact, the heating process appears to make the fiber more soluble and, therefore, more useful to the body.
Potassium and Folate
Consumers always can count on beans to pack a powerful nutritional punch. Not only an excellent source of protein and iron, beans also are excellent sources of thiamin, dietary fiber and potassium – which is important for regulating blood pressure and kidney function. They’re also a good source of folic acid, which recent studies indicate plays a critical role during pregnancy. While the FDA requires no labeling information for folates, the USDA nutrient database shows beans can provide 20 to 40 percent of the Recommended Daily Intake (RDI) for folate. All of these nutrients hold up well in the canning process, making them similar to dried varieties that are cooked from scratch.
Apricots, asparagus, oranges, grapefruits, pineapple, strawberries, spinach and tomatoes all are significant sources of vitamin C. Although small amounts of vitamin C are lost during heat treatment, most of what is lost ends up in the liquid in which the product is packed. The C retained after canning remains stable during the one- to two-year shelf life of the canned product.
Canned poultry and fish – considered protein foods – are comparable to their fresh-cooked counterparts in nutritional value, since protein is not affected by heat treatment. This makes the canned varieties convenient alternatives to fresh-cooked, since they require much less preparation time.
The canning process actually is responsible for higher calcium levels in canned fish than in freshly cooked.
Thiamin, one of the B-complex vitamins, is obtained by eating meats or legumes. Although this vitamin is not particularly stable when heated, it survives the canning process well, making canned meats and beans comparable to their freshly cooked counterparts.
Convenient, Nutritious Recipes From a Can
Canned foods are convenient – particularly when used as recipe ingredients. But what many consumers don’t realize is canned foods are not only quick, delicious alternatives to fresh, but are just as nutritious when prepared for the table. A nutritional analysis of five popular recipes shows that using fresh and frozen ingredients in recipes provides comparable nutritional value to using canned.
For example, a basic Chili recipe contains significant levels of nutrients for an average adult woman in one serving. Most of these nutrients come directly from the canned ingredients and are comparable to the nutritional values obtained by using fresh alternatives.
According to the study, a Spaghetti Sauce recipe using canned tomatoes provides more fiber, potassium, vitamin A, vitamin C, calcium and iron than the same recipe using fresh tomatoes. And with canned ingredients, no dicing or pureeing is necessary, cutting down on preparation time. Spaghetti Sauce, as well as Tomato Vegetable Soup, have good vitamin A, vitamin C and folate content, whether they’re made with canned ingredients or fresh-cooked tomatoes. However, the big advantage in using the canned varieties is easy preparation and year-round availability.
Pineapple Upside-Down Cake, and particularly Peach Cobbler, provide fiber, vitamin A and vitamin C, whether prepared with fresh or canned product. However, canned peaches and pineapples come peeled and sliced, drastically cutting down preparation time.
Generally speaking, if a fruit or vegetable is considered healthy and nutritious when it is fresh, it also will be nutritious in its canned form. The reason – the heating process used in packaging canned products causes only minor loss of most nutrients, similar to what is lost when fresh foods are cooked at home.
Once the product is canned, it usually maintains its nutrient levels, even after one to two years of storage. This is particularly important, since canned products are harvested at the peak of ripeness and usually canned only a few hours after they’re picked, sealing in the nutrients.
Meanwhile, "fresh" fruits and vegetables often are picked before their nutrient content has peaked and may spend as many as 7 to 14 days in transit, even before they hit the supermarket. Add to this the number of days they spend in the store – and in the crisper drawer before they’re consumed – and it’s easy to see that "fresh" can just as easily be found in the canned food aisle as in the produce department. And unlike many fresh items, canned products are available year-round at their peak quality.
Safety That's Packed In
In addition to being nutritionally comparable to their fresh and frozen counterparts, canned products are one of the safest forms of food, according to the University of Illinois study. Canned products are heated and vacuum-sealed, destroying microorganisms that cause foodborne illnesses, while locking in both flavor and nutrients in a recyclable steel can.
Because the freshness of canned foods is sealed in naturally, no preservatives are necessary. Though salt is often added to canned products, it’s used only to enhance flavor. Low-sodium and sodium-free alternatives now are widely available for consumers who wish to lower their sodium intake.