Q & A Thursday: which are better canned or fresh vegetables?
Posted by kathryn in Vegetables and Q & A Thursday
Following my post on using frozen vegetables when you’re busy Bruno has asked about canned vegetables – do they lose nutrients in the canning process?
Much like frozen vegies, there are some vitamin and antioxidant losses in tinned vegetables. But they can still be a useful dietary back up – especially if your fresh vegies are starting to look a bit tired.
How fresh is “fresh”?
Vegetables are canned soon after harvest – at their nutritional best. Whereas with fresh vegetables, there can be a time lag between harvest and them reaching your dinner plate.
And during that time nutrients degrade. So your fresh vegies can have significantly reduced vitamin and antioxidant levels than when they were first picked.
It depends on the fragility of the nutrient
The most likely nutrients to be affected by the canning process are the water soluble vitamins, such as vitamin C and the Bs. These are also the most likely nutrients to degrade during that time lag between harvest and you using them.
And the nutrients lost during the canning process are often similar to those lost if you’re vegetables are less than fresh.
Other nutrients are more robust and harder to destroy. While some antioxidants, such as lycopene actually improve and become more bioavailable during processing.
Choice tested the differences between fresh and week-old, raw vs cooked and canned and frozen vegetables. They had some interesting results, which can be viewed here. As you’ll see in most instances canned and frozen vegies were better than week-old vegetables. In some cases they were better than “fresh”.
Watch the salt
The main negative about canned vegetables is they often have salt added. This isn’t necessary to the canning process. So try to pick vegetables without the extra salt.
What to do
- Eat plenty of vegetables every day – fresh, frozen, canned matters less than the core dietary issue of getting those five daily serves necessary for good health.
- Eat a variety of vegetables to maximise your nutrient intake.
- Eat both raw and cooked vegetables – they both have nutritional benefits.
- Shop strategically – buy fresh vegies for the beginning of the week and then back that up with frozen and canned.
- Use your green vegies first – these are the ones that degrade at the fastest rate, so eat them at the beginning of the week.
What is Q & A Thursday?
This post is part of Q & A Thursday – a monthly burst of blogging, where you get to dictate the subject matter. Q & A Thursday is all about simple, practical answers to food and diet dilemmas sent in by readers.
If you have a question you’d like answered send me an email. For more information you can take a look at the Q & A Thursday archives.
03 April, 2008
Comments
Thanks, Kathryn.
A great one to hold its powers is the tomato, that is as long as you aren’t getting the super-sodium-ized cheap grocery versions… Tomatoes are the most common produce in my diet (as they go so well with everything), and they are great source for Lycopene. Some good info on the tomato and lycopene here.
I need to work more variety into my diet, I always have such grand plans at the start of the week’s shopping and then I end up with all this produce I never use and feel all guilty about it. Perhaps more canned than not? Seems counter intuitive, but perhaps with your advice here I can make it work.
Hi there Du. I’m a big fan of lycopene, as you can tell from the name of my blog! If you do end up wasting a lot of food, then yes I’d recomend buying more canned and frozen vegetables and trying to make them work in your diet. While it may seem counter-intuitive, the most important thing is to try and get plenty of vegetable serves in your week. Fresh, frozen or canned – whatever works best for you.
If you do end up with lots of leftovers, then you can always put them together in a soup? It’s something I do quite regularly – as I write about here.
Hi Kathryn, I’m loving your blog so far! Very informative and you’ve got some great recipes. I’m always looking to add more veggies to my diet, and reading your lovely, lovely legumes made me think of green peas. But when I googled the GI of green peas (I’m just starting to watch the GI of my meals), some sites say the GI is 48, while others say it’s 68. Needless to say, I’m somewhat confused, because one is quite low, while the other is bordering on high. Would you happen to know which one it really is?
Amber, thanks for your comment. The variation in GIs comes from different testing methods and the slight variations in ingredients which occurs between different countries. Which does make it confusing.
The most consistently accurate results I’ve seen are produced by the GI group at Sydney University. Their mean testing score for peas is 48 – so squarely in the low GI category.
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