By Emily Schilling, Dietetic Intern
Brigham and Women's Hospital
The U.S. Department of Agriculture (USDA) encourages us to fill half of our plates with fruits and vegetables. And why not? Fruits and vegetables are packed with the vitamins, minerals and fiber our bodies need to stay healthy.
A diet that has at least 2 ½ cups of fruits and vegetables per day can also help you achieve or maintain a healthy weight, and may even reduce the risk of cardiovascular disease and some cancers.
Eating fresh fruits and vegetables daily can be a challenge for some people because:
- They're not readily available.
- They may be too expensive.
- Preparing them can be inconvenient.
These may lead people to forego fruits and vegetables all together. In fact, the average American only eats about 50% of the amount of fruits and vegetables recommended by the USDA. So, how can you get more plant foods into your diet?
Luckily, fresh isn't necessarily best when it comes to produce. Studies have shown fresh, frozen and canned fruits and vegetables to be nutritionally similar. Frozen and canned sources of produce are often cheaper. And they are already washed and cut, making them more convenient. Here are some tips for buying and using fresh, frozen, canned, and dried fruits and vegetables.
We typically think of fresh fruits and vegetables as being more nutritious than frozen or canned. However, nutrient levels decrease from the time fruits and vegetables are picked to the time they are eaten.
For example, an apple picked straight from a tree has higher levels of nutrients than an apple that was picked a few days ago then shipped across the country. In fact, a study by Favell (1998) found that the vitamin C content in carrots decreased by 27% and in broccoli by 56% within 1 week of storage at room temperature.
Here are some tips for buying and using fresh fruits and vegetables:
- Take advantage of the lower prices of seasonal fresh produce. To find out which fruits and veggies are in season, visit www.fruitsandveggiesmorematters.org.
- Local produce stands and farmer's markets may offer the freshest fruit.
- Don't "stock up" on fruits and veggies that will spoil before you can eat them. In general, apples, oranges, potatoes, kale, onions, carrots and garlic tend to keep longer than other produce.
- Refrigerate produce to slow the loss of nutrients.
- Try freezing or canning fresh produce on your own to save for later.
- To learn more about the shelf life of specific fruits and vegetables and how to store them, visit www.eatbydate.com.
The frozen section at the grocery store offers convenient and versatile ways to get more fruits and veggies into your diet. Freezing preserves nutrients. In fact, studies have shown frozen produce to have equivalent antioxidant activity compared to fresh produce, and greater levels compared to some canned produce. Additionally, some varieties of frozen produce may be cheaper than fresh, depending on the time of year.
However, freezing can contribute to nutrient loss. First, the blanching process that precedes freezing may lead to loss of some B vitamins. Green peas and beans lose 9% to 60% of B1 and B2. Spinach loses 30% of its B1. These losses appear to be similar to those lost during cooking in fresh vegetables. Additionally, the duration of storage may affect nutrient content. Vitamin C losses from frozen spinach are insignificant at 1 month, 26% at 6 months and 30% at 12 months of storage. Here are some tips for buying and using frozen produce:
- Avoid frozen vegetables in sauce or butter – this adds extra calories and salt.
- Look for non-starchy mixed vegetables, such as broccoli, zucchini, spinach, carrots and cauliflower.
- Try to avoid storing frozen vegetables long term.
- Follow heating instructions on packages. Only microwave frozen vegetables in the package if it is intended for microwave use.
- Try adding frozen berries to oatmeal or blend with yogurt for a tasty smoothie.
- Try using frozen vegetables in soups, pasta dishes, stir-fry and casseroles.
Canning is another method that preserves nutrients. Canned foods can last for years, and offer up to a 20% savings when compared to fresh produce.
Canning has little effect on protein, fiber and mineral content. Levels of some B vitamins in canned produce appear lower than that of fresh produce. Levels of vitamin C and folate are the same or higher than those found in fresh. Canned tomatoes have higher levels of vitamin E and carotenoids than fresh. And B vitamin levels are similar to those seen in fresh tomatoes.
Here are some tips for buying and using canned produce:
- Look for "low sodium" or "no added salt" on the label.
- Drain liquid from canned vegetables and rinse to decrease the salt content.
- Look for fruit packed in water and avoid fruit packed in syrups and juice.
- Juices and fruit purees do not offer the benefit of fiber, so choose whole fruit instead.
- Double check the expiration date on the can.
- Don't use cans that are deeply dented, leaking, rusted or bulging; they may not be safe.
Dried produce can be another cost-effective way to increase fruit and vegetable intake. Drying fruits and vegetables has no effect on fiber and vitamin A content. However, a significant amount of vitamin C is destroyed in the drying process. Dried produce has to be soaked first in water. This may require more preparation time. Here are some tips for using dried products:
- To retain the most minerals and B vitamins, reuse the water that the produce is soaked in.
- Use dried produce within one year for the best retention of nutrients.
- Limit how much dried fruit you eat, as it's higher in calories and sugar than whole fruit.
- For more information on how to use dried beans and legumes, see Are Beans the Magical Food?
- Reconstituted dried vegetables have a different texture than you might be used to, so try using them in soups, stews, casseroles and sauces.
The Bottom Line
Eating a variety of fruits and vegetables in any form is better than not consuming them at all. Fresh, frozen, canned and dried produce are cost-effective and great ways to increase your intake of fruits and vegetables. In fact, fresh, frozen and canned options have similar nutrient contents. Additionally, freezing or canning actually preserves nutrients in fresh produce. So, next time you're out buying fruits and vegetables, consider buying them in a variety of forms to reap the health and cost benefits.
Emily is a dietetic intern at Brigham and Women's Hospital. Originally from Indiana, she earned her bachelor's degree in dietetics from Indiana University in 2013.
U.S. Department of Agriculture. Dietary Guidelines for Americans 2010. Available at: http://www.health.gov/dietaryguidelines/dga2010/DietaryGuidelines2010.pdf.
Rickman J, Barrett D, Bruhn C. Nutritional Comparison of Fresh, Frozen, and Canned Fruits and Vegetables Part 1: Vitamins C and B and Phenolic Compounds. J Sci Food Agric. 2007.
Favell D. A Comparison of the Vitamin C Content of Fresh and Frozen Vegetables. Food Chemistry. 1998;62:59-64.
Simpson A. Nutritional Comparison of Cooked Fresh and Frozen Vegetables. University of Chester, United Kingdom. (Unpublished Master's Thesis). 2013.
Miller S, Knudson B. Nutrition & Costs: Comparisons of Select Canned, Frozen, and Fresh Fruits and Vegetables. Am J Lifestyle Med. 2014.
Durst R, Weaver G. Nutritional Content of Fresh and Canned Peaches. J Sci Food Agric. 2013;93:593-603.
Academy of Nutrition and Dietetics. Fresh, Canned, or Frozen – Get the Most from Your Fruits and Vegetables. 2013. Available at: http://www.eatright.org/Public/content.aspx?id=6442451032. Accessed on August 1, 2014.
DiPersio K, Sofos J. Drying Vegetables. 2014. Available on the Colorado State University Extension website at: http://www.ext.colostate.edu/pubs/foodnut/09308.html.