Ah veggies–we know we should eat more of them, but do we? Maybe… maybe not.
Also, there’s confusion about which form of veggie is healthiest. As a Registered Dietitian, I often get questions on this topic. Some people think if they eat canned or frozen veggies, they are getting so little nutrition, they shouldn’t eat them at all. I’m here to throw the yellow flag on that myth, as well as the one that says fresh is always best! Because as you’ll see below…it depends! And I’ve even got the references below to back it up!
Which Type of Veggies are Best?
Which vegetables are better—frozen, canned, bottled or fresh? It’s a toss-up—depending… Nothing beats freshly picked food straight from your own garden.
However, research shows that frozen vegetables can actually have a similar nutrient content to fresh, and even some canned vegetables have higher antioxidant availability compared to fresh. How you cook your veggies also matter; the healthiest is steaming and pressure cooking, followed by baking/grilling. When foods are over-cooked or cooked in a lot of water they lack flavor, become mushy, and lose water-soluble vitamins like riboflavin, folate and vitamin C.
Nutrient Content Varies
Fresh vegetables may not be very fresh by the time you buy them, and they’re even less fresh if they stay several days (or weeks) in your refrigerator. For example, fresh peas lose 50% of their vitamin C content in the first 24-48 hours after picking.1 Fresh spinach, when left in your refrigerator for 7 days, can lose 75% of its vitamin C content. Vegetables such as green beans, sweet corn and peas contain similar levels of vitamin C, fiber, magnesium, and potassium as fresh vegetables.2 The vitamin C level in quick frozen green beans, carrots and spinach are comparable to that of fresh vegetables.3
In some cases, carotenoids like lycopene are better absorbed from foods after they’ve been cooked or processed. For example, the bioavailability of lycopene from tomato sauce is higher than from fresh tomatoes.4
Canned vegetables may not seem as nutritious as fresh, but research shows that by the time the food gets to your table, the nutrient content of fresh, frozen and canned is similar.5 If canned or bottled is the only way you eat vegetables that are lengthy to prepare—beans or pasta sauce, for example—then the payoff is worthwhile. Buy pantry foods in BPA-free cans, in glass jars or Tetra-paks when possible. However, canned foods have much more sodium than fresh or frozen.
Caring for Vegetables
- Store veggies in your refrigerator crisper in their bags.
- To keep lettuce and other greens fresh, remove rubber bands and ties, wrap in paper towels and then store in their bags. Wash right before eating to delay spoilage.
- If you like to chop up your vegetables ahead of time so that they’re easier to eat later, store them in a zipper bag, letting the air out first. Wrapping them with paper towels save some nutrients that are light or air sensitive.
- Avoid soaking vegetables for long periods of time; soaking for 2 minutes is the best way to remove dirt from some foods, like spinach or strawberries. But if you leave vegetables soaking too long, they’ll lose water-soluble vitamins.
Veggie Cooking Tips
- To cook vegetables in the microwave, add 1 or 2 tablespoons of water to veggies in a glass bowl and vented cover (like the one pictured here).
After the microwave cycle is finished, let the vegetables stand a few minutes while covered to continue cooking. This method is wonderful for cooking cubed potatoes; they are so moist, and they taste great without any added fat.
- If you want veggies to stop cooking so they stay crisp, immerse them in cool water.
- When stir-frying, put more dense vegetables in the pan first. For example, start with onion, and dry spices if you’d like to brown them, then add carrots, celery, cabbage, and broccoli. At the end, add softer vegetables such as garlic and fresh herbs, peas, mushrooms, and greens.
- For steaming, a stainless steel, bamboo or silicone steaming basket is cheap and efficient. Or purchase a “universal steamer” pan, which fits over a traditional saucepan, and lets you cook pasta and steam veggies at the same time. (Don’t you just love multi-tasking products?)
- When cooking in water or steaming, use just enough water to prevent scorching. Cut large vegetables in smaller pieces to shorten cooking time.
- Pressure-cooking has seen a comeback as a faster, nutrient-friendly way to cook. A wonderful resource for pressure-cooking (and vegetarian eating) is Jill Nussinow MS, RD, also known as The Veggie Queen. Her newest book The New Fast Food: The Veggie Queen Pressure Cooks Whole Food Meals in Less than 30 Minutes as well as a blog, recipes and cooking tips can be found at theveggiequeen.com.
Check out Part Two of the Eat Your Veggies series, 13 Ways to Eat More Veggies.
- Bruhn CM, Rickman JC, Barrett DM PhD, Review Nutritional comparison of fresh, frozen and canned fruits and vegetables. Part 1. Vitamins C and B and phenolic compounds. J Sci Food Agric 87:930–944 (2007)
- Makhlouf J et al. Some nutritional characteristics of beans, sweet corn and peas (raw, canned, and frozen) produced in the province of Quebec. Food Research International. 1995; 28:253-259.
- Favell DJ. A comparison of the vitamin C content of fresh and frozen vegetables. Food Chemistry. 1998;62:59-64.
- Shi J., LeMaguer M. Lycopene in tomatoes: chemical and physical properties affected by food processing. 2000; 40(1):1-42.
- Bruhn CM, Rickman JC, Barrett DM PhD, Review Nutritional comparison of fresh, frozen and canned fruits and vegetables. Part 1. Vitamins C and B and phenolic compounds. J Sci Food Agric 87:930–944 (2007).