Are Your Vegetables Nutritionally Impotent?

It’s incredibly disheartening to learn that after stocking up on broccoli, forgetting you were going to be out of town for 10 days, using it when you get home, removing the brown, chopping it up, steaming it til it’s soft – that only a fraction of the vitamins remain*.  But surely,  any vegetable even a nutritionally impotent, is better than no vegetable!

A broccoli today is worth more than a broccoli tomorrow.   Vegetables have a set amount of nutrients when harvested and begin to lose them the minute they are cut off from their food source  Once harvested, they begin to consume their own nutrients in order to stay alive. This decline is hastened by the things we do to them.

What we do that destroys nutrients

  • Store. The longer we (or the grocer) keep vegetables before using them, the more nutrients vanish.
  • Cut.When a vegetable is cut, it perceives it as an attack; it goes on the defensive and activates enzymes which destroys it’s own nutrients. (Better to destroy yourself than be destroyed). The brown discoloration is the evidence.  The more pieces you cut it into before you cook it, the more defensive the vegetable gets.
  • Cook. Boiling makes it easy for nutrients to leach into the water. Over-cooking via any method diminishes nutrients by breaking down the cells.
  • Freeze. Frozen food is pre-cooked to inactivate the enzymes (so it wont go on the defensive and turn brown); this makes it even more susceptible to over cooking once it gets into your pot. Vitamin C appears to be particularly vulnerable to freezing.
  • Juice. Juicing breaks the vegetable into such tiny parts that the nutrient loss begins rapidly.  Very few nutrients will be left in the glass 24 hours later.

How to minimize destruction

  • Shorten “field to fork” time. Buy the most recently harvested vegetables you can.
  • Seal in airtight bags to lower oxygen levels.
  • Delay cutting.
    -Buy the whole vegetable vs. pre-cut and bagged. (If you do buy bagged, use them quickly once opened.). And note, “baby” carrots are not baby carrots, but baby “shapedadult carrots!
    -Cut right before you cook. Don’t peel or pre-cut and store in fridge.
    -Cut into extra large sizes to cook and cut smaller after cooking.
    -Peel vegetables (beets, carrots, potatoes) after cooking, as the skin helps keep nutrients in.
  • Avoid boiling. Use steam so the nutrients wont leach into the water. Stir-frying, roasting are also good alternatives. (I am not a fan of microwaves so if you have the choice of other methods, use them.)
  • Fro-veg is better than no-veg, but eat frozen only when fresh is not practical.
  • Drink “just-juiced” juice.
    - Drink it immediately after you make it.  Don’t save it for tomorrow.
    - Avoid buying bottled vegetable juice which was juiced many days/weeks before and has also  been pasteurized (which defeats the point of fresh juice).

Any other tips or thoughts on maximizing the life of vegs?

(*Update: Many of you have asked if I could more specific on % nutritional loss.  I wish I could.  It seems to be undebated in the industry that loss does occur with all the methods discussed above, how much though is not agreed on, in part because there are no comprehensive studies. There are some minor more anecdotal studies,  but for a major study to be conducted, it has to be funded by a party who has a vested interest in the outcome… smaller farmers who sell you vegs picked that morn, have the most to gain by a study showing nutritional degradation. They also have the least to spend. )

Photo (Disclaimer):  I know we’re talking about vegetables and the photo is of a tomato and a tomato is a fruit. But a smashed tomato is more dramatic than chopped broccoli.  Copyright© Michelle Madden


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  • Lisa

    I think I *might* have learned some of this in grade 9 biology but it was never this simple or practical as it all seems now! I love how you give us just enough science to make it logical and interesting, but not enough to lose me!

  • Juliana

    Which is why every other culture outside of the US prefers to shop daily for their foodstuffs! Thank god for greenmarkets, if only they delivered. Yeah, I know, CSA thyself!

    • Michelle

      So true. For those wondering, CSA stands for Community Supported Agriculture … Juliana, can you tell us a bit more about it?

  • Juliana

    CSAs have sprung up around the city and the country. Basically, it’s a farm that ‘shares’ its fresh produce, including raw milk, cheese, and whatever is in season, with a group of members, for a price. You sign up for a year or a season, and on a regular basis receive (or pick up) a box of what’s available – artichokes in the spring, kohlrabi in August, kale in the fall and root vegetables in the winter. There are green buildings in NYC that now offer this service as part of their marketing campaign if you can believe it. It’s not cheap, but gets you fresh stuff without the shlep.

    • http://www.thesweetbeet.com Michelle

      Thanks! I have never joined a CSA since I’m fortunate to be close to a farmers market but am going to look into it this winter. For anyone also looking: http://www.LocalHarvest.org is a national site where you put in your zip, click on CSA, and up pops those closest to you.

  • Jiggsy

    Michelle a few questions. You often hear frozen is better because it goes right from it’s ultimate freshness to the bag and the nutrients are locked in at their peak. So the logic would be if it sits in it’s freezer frozen until use it’s better than getting fresh and letting it sit in your fridge for two days. Which of course goes agains’t our natural logic of fresh from the grocer, can you expand on this? Also you said frozen vegs were pre-cooked is this true for all frozen?

    • http://www.thesweetbeet.com Michelle

      Here’s the deal with frozen:
      - Yes, it is packed soon after being picked so nutrients are high at packing time
      - All vegs (that I know of) are blanched pre-freezing (spinach for ex, is thoroughly cooked by the time its frozen)
      - Prob with freezing though, is that it damages the plant’s tissue. there’s no way around this. It’s why they will never become crisp again when thawed and it does affect the nutrient level. How much, hard to say, but it does.

      So … If you’re going to use them within a few days, I’d buy fresh. But if the Q is frozen v. fresh where the fresh will sit for a week or more in the fridge? I’d still go fresh if you store the veg whole, in a tight fitting closed bag and can ensure the veg still plump and edible at the time of eating. But …. if you think that will not be the case, go frozen. But remember to re-seal the bag super tight and stick in back of freezer where it’s colder.

      • Jen

        Michelle – a friend of mine got me hooked when you first launched your site and I find it so fascinating and simple to grasp – thank you for that! And love the flow of conversations that always follow-up your articles, like the one above. I read about the CSA and just found one in my area that will deliver to my door within 48 hours of harvesting. Awesome.
        Quick food question, about two years ago I started hearing horrible things about the use of chlorine on baby “adult” carrots and stopped buying them for my family. Have you heard anything negative about them?

        • Michelle

          I have heard faint whispering of this and I can’t confirm or deny, but here’s my take :

          - If you can, buy adult carrots and use these instead. Carrots, unlike say the green vegs, lose their nutrients more slowly and don’t leach their nutrients as easily into water (beta carotene is not water-soluble), which means you can peel,cut and store in the fridge in water or damp bag, w/ less degradation than w/other vegs.
          - If you buy baby carrots, buy organic. The standards for organic are more rigid, although chlorine, as far as i’m aware, *can* be used even w/ organic
          - Though chlorine at very high levels *is* toxic, we drink it everyday in our water (Brita filters do not remove it; only way to eliminate it is to let it sit for many hours exposed to the air, so it evaporates). It makes sense that a very mild chlorine bath would be used to eliminate bacteria before packing, but as for the concentration of chlorine and how much is absorbed, that I can not say for sure.

          I will look more closely into this and if others have insights, please share!

  • dennis madden

    Where do you get all your information on nutrition?

    • Michelle

      If it’s not something I’ve discovered myself from either eating the food or cooking it, then the info comes from a combo of sources: reading food labels, product websites, asking questions of people that work in food and health food stores, talking to vendors at farmers mkts, reading and cross referencing articles online (there is a lot that is incorrect so you have to know enough to know what feels right and wrong), wikipedia, and many wonderful dead-tree style books! One treasure trove of fascinating food facts is “On Food&Cooking, The Science&Lore of the Kitchen” by McGee.

      Much of nutrition is fact but a lot is opinion. I try to differentiate between the two, but it’s very easy for ones personal opinions and beliefs to quickly become “facts”….

      If ever you read something (on this site or elsewhere) and you’re curious about the source or the “truth” behind it, pls ask!

  • Abby

    My First-Year Seminar in college (a writing-intensive freshman class) was on nutrition, and I can’t remember the specifics now, but we learned that certain vegetables actually do better after being cooked in certain ways. I want to say spinach and/or broccoli were on the list; it was something along the lines of certain nutrients in those vegetables only become accessible to our systems after cooking. Of course, this came along with the knowledge that overcooking anything will deplete its nutrients, but I want to say one of the examples was that if you stir-fry spinach for a couple minutes you will get more of certain nutrients than if you eat it raw. Have you heard anything like this?

    • Michelle

      You’re correct … most nutrients do suffer some degradation when the veg is cooked but there are exceptions.

      The two nutrients that can be enhanced by cooking are starch and beta carotene (which our body converts to vitamin A). With starch, our digestive system cant get past the tough fibres so cooking makes them accessible (think potatoes, yams, broccoli – but dont over cook it.) Betacarotene is found in carrots as well as dark green leafy vegetables, and it’s bio-availability to us, *can* be enhanced by very brief steaming, but avoid the tipping point into nutrient destruction. As a side note, Vit A is a fat soluble vitamin which means it is better absorbed with the presence of fat, so add some butter or oil to those veg after the quick steam to access even *more* of the Vitamin A!

  • Brenda

    I’m been searching and searching and can’t seem to find whether smashing up veggies also diminishes their nutrients? I’ve heard this everywhere!

  • Emilie

    Hello! I have just found your awesome site, and I love it. Great information! I was wondering if you have seen this article about the level of antioxidants: http://www.ncbi.nlm.nih.gov/pubmed/19397724 It details the %losses of antioxidants for each method of cooking for different vegetables. Thought you might like it.

    • Michelle

      Had not seen it but will definitely check it out! Thank you!

  • jenny

    hi michelle, i know im a bit late to this convo but i love this post. i revisit it mentally with each veggieful meal i cook. on the topic of juicing… i dont have a juicer at home and was considering the BPC 3-day cleanse for convenience sake but it seems to me that if i get the juice on sunday and im drinking it mon tues and wed that the nutrients may fade significantly by the time i ingest? am i right? is it worth all that moolah if im not getting that most freshly extracted nutrient goodness?
    thank you very much for the endless ways in which you have already informed me.
    jenny

    • http://www.thesweetbeet.com Michelle Madden

      The “word on the street” (and there appear to be no official stats on this), is that after more than say a couple hours post-juicing, much of the nutrients are lost. I think if you were to seal the container super tightly, allow limited air into it and place it in the fridge you might be able to extend its life, but if you’re thinking of allowing it to sit for 2 or 3 days, many/most of the nutrients will be gone.

  • ???

    I agree with you on a lot. I still think that it is still good to eat veggies or fruit even though it may be more than a few days old and not fresh. Maybe (for me) it is just genetics but eating fruits and veggies (no matter how old, if they haven’t gone bad yet) still benefit me than eating none at all. I am super healthy but I don’t eat much fresh fruits/veggies. I try to limit how long something is in my fridge. Most of the time I will buy two days worth of veggies and 1.5 weeks worth of fruits at a time. Most of the time I get to them every day. Sometimes I am too busy and they sit there a little longer than intended. I try to eat most things raw or just stir fried. I do agree with you. I just think that maybe (within reasonable limits) nutrition isn’t lost too much. I used to be a lot worse with veggies and fruit. Buying a weeks worth at a time but I was STILL just as healthy. I was actually even healthier in my past because I only ate what I could make from scratch and stayed away from unhealthy foods, processed foods and fast foods. Now I eat 75% to 100% healthily depending on the day. I know my healthy eating (even though it isn’t too fresh) has a great affect on me. For example, my skin is always glowing now. Obviously picking veggies and fruit right off the source and immediately eating it is WAAAAAY more healthier. I just mean (from my own health experiences) that even after a week for already picked fruits and veggies, their nutrition isn’t lost to the point that it wouldn’t benefit a persons health to eat them regardless. I know that a lot is lost after a week but I do believe there is still a lot left from them to offer to us nutritionally. This wasn’t meant to be argumentative (I am sorry if it came off that way.) I just wanted to give my experience from my then past and my now food experience. The fresher the better and I also appreciate that you stay away from opinion as much as possible. Could you please give me an example of how eating fresher (if you have any experience to give) has benefited you much more than eating foods that are less fresh? I’ve never been able to eat foods that fresh (for the most part). I would like to know if maybe (if you have) you feel even better and by (a rough estimate) how much better? Please and thank you.

    • http://www.thesweetbeet.com Michelle Madden

      It’s pretty hard to get scientific, accurate data on just how much of the nutrients are lost over time. There is broad agreement though that nutrients ARE lost, so the sooner you eat the produce from the time its picked the better, but I agree with you – week old spinach is still better than no spinach at all.

  • Dar

    Thank you for the information above. I am fighting breast cancer at this time in my life and trying to keep Carrot, Beet, Apple and a little Garlic juiced and available to drink all day and at night with dinner. Getting this accomplished in the evening is a breeze, it is during the day while at work and first thing in the morning as I am running out the door. So I thought last night to juice ahead and freeze it. But when i looked at it a moment ago before drinking it the texture was gone and it looked very watery. So I Googled my question and you answered it. I guess I am going to need to get up a bit earlier to juice fresh and bring my juicer and vegatables to work.
    Thanks Again!

  • Markie fresh

    Just eat organic fruits and vegetables from the only certified organic grocery store on the planet…. Ya u know who I’m talking about. Eat fresh, feel fresh. Boom. I just ate a organic carrot and it might of blew my mind!!!! Pow!

  • chuckk

    Is it safe to drink the water left over after steaming vegetables?

    • http://www.thesweetbeet.com Michelle Madden

      Go for it. I would probably opt for using it for a soup, but if drinking it straight’s your think. Bottoms up!

  • Jillian

    Is all of this true for fruit as well?

  • Michelle

    Some of it. Unlike vegetables, many fruits ripen after picking (bananas, peaches, mangoes) their starch converted to sugar making it easier to digest. But in terms of nutrient destruction from cutting them up, yes, that happens too. So if possible, buy fruit whole (a small whole melons vs a lg one cut in half) and do the cutting right before the eating.

  • http://www.findyourbalancehealth.com Michelle @ Find Your Balance

    More important is probably to eat veggies, however you eat them. And one day I wish upon a star I’ll have a garden :-)

  • http://reallyliteral.blogspot.com/ christina

    V informative. Thank you! xxx
    http://reallyliteral.blogspot.com/