Welcome to the 9th post of One Simple Change, my year-long series of tips geared at “healthifying” your lifestyle, one week at a time.

(I’m pretty sure I made up the word “healthifying”, but I think you know what I mean ;))

Today, I want to talk about the benefits of consuming leafy greens, because if you’re interested in eating for health, these vegetables simply must be a part of your diet. Leafy greens are low in calories and carbohydrates, yet extremely high in nutrients: they contain noteworthy amounts of calcium, magnesium, potassium, iron, vitamins A, C, E, and K, as well as folic acid, and fiber. They’re also full of beneficial phytochemicals and carotenoids.

Not sure what I mean by leafy greens? Here’s what I am talking about:

  • kale- all varieties (including red, curly, and black (aka Tuscan, Lacinato, or dinosaur kale)
  • chard- all varieties (including red, green, and rainbow)
  • collard greens
  • mustard greens
  • bok choy and other “Asian” greens like tatsoi and mizuna
  • arugula, frisee, endive*, chicory, radicchio, escarole, watercress
  • sorrel, lamb’s quarters, and other wild or cultivated “salad” greens (baby or mature); cilantro and parsley, while herbs, can also be considered leafy greens
  • beet greens
  • broccoli rabe
  • cabbage- all varieties (broccoli and kohlrabi are in the cabbage family, and while not technically leafy, are still green and very healthy)
  • spinach
  • wild greens like dandelion, purslane, nettles, and chickweed

Now I wish I could simply say “ok- go eat as much as you can of what’s on the above list” and be done with it. But it’s not that simple, because I want you to be informed about a couple of cautions when it comes to eating greens.

First, it’s important to know that cruciferous vegetables can suppress thyroid function when they are eaten to excess in their raw form. This means that you should not eat tons and tons of raw broccoli, cabbage, kohlrabi, kale, collards, etc. To the best of my knowledge, these vegetables are best when they’re cooked or lacto-fermented. Does that mean you should not eat cabbage salads? Or kale salads? No. It just means you shouldn’t live on them, and that if you have thyroid issues, you should probably limit them further. I’ve featured raw kale salads on this site several times- I love them- but I mostly eat kale in it’s cooked form. And really, honestly, I think the healthiest way to eat cabbage is in it’s naturally cultured form: as sauerkraut, or in kimchi, etc. This is when it is most easily digested and contains the most nutrients.

Another caution I want to point out about greens is that certain ones- beet greens, chard, and spinach, and also parsley, purslane and lamb’s quarters- contain high amounts of a compound called oxalic acid. Oxalic acid inhibits mineral absorption (particularly calcium and iron): a real bummer, since the minerals in these greens is what a lot of us are after…oxalic acid also contributes to kidney stones. Cooking reduces the oxalic acid in these veggies, so the main concern is if you eat large amounts of them raw. Now I personally eat a fair amount of raw parsley (and also purslane), because honestly before researching this piece, I didn’t know these were high in oxalic acid (they have so many nutrients, I thought I was doing myself good, but maybe now I’ll back off on eating so much of them raw). For years, however, I’ve steered away from eating lots of raw spinach, etc., because of the oxalic acid issue. I do eat spinach salads on occasion, but I generally choose to eat it cooked. I think if you’re concerned about your calcium intake/absorption, this is really something to think about.

In light of these issues, I am a little concerned about the green smoothie “trend”, because if you’re throwing large amounts of raw greens into smoothies once or even twice a day, and depending on them as the sole vehicle to get greens into your diet, you might be overdoing raw kale (which can suppress the thyroid gland); you might also be overdoing raw spinach and getting too much oxalic acid.

Now I am not telling you not to have green smoothies- I drink them on occasion- but I do think it’s important to have balance with leafy greens (as with all things in the diet). This is why I think it’s good to enjoy a portion of your daily greens raw (and some of this can be in smoothies), but also have some of them in cooked form, and some in lacto-fermented form. I am a huge, HUGE, salad eater, so please don’t think I am telling you not to eat raw greens. I eat a very wide variety of the greens listed above, and I think this is really important- variety is key! The wild greens in particular (like dandelion and nettles), are some of the most nutritious foods on the planet, and definitely should not be overlooked.

All things considered, though, I am definitely a kale fanatic. We go through tons of it in this house- I put it in salads (in moderation), soups, stir-fries, eggs, and many other dishes. When I was on the way home from Colorado last week, I found this recipe for Buckwheat Soba Noodles with Kale and Walnuts in the March issue of Oprah magazine, and I was so pleased to see that the recipe is from my friends Phoebe and Cara of Big Girls, Small Kitchen! I made it the day after I returned home with just a few changes: I used hazelnuts instead of walnuts, and I added a few anchovies and quite a bit of crushed red pepper flakes. I also added a bit of lemon juice (I learned a while back that you absorb the minerals in greens best if you eat them with a little acid). It’s a quick and very nutritious meal- one I definitely recommend (make sure to use 100% buckwheat soba if you are gluten-free, and make sure not to overcook the noodles).

soba noodles with kale

For 52 other ways to eat kale, make sure to check out Hallie’s awesome post.

*I am being compensated for my efforts to promote California endive; all opinions are 100% mine.

So are you eating lots of leafy greens? Could you do better? Do the cautions above concern you? I’d love to hear about whether you’re “in” for this week’s One Small Change!

 

19 Comments

  1. 1

    Simona — March 2, 2012 @ 5:56 pm

    I didn’t know about the effects of thyroid function. I am also a kale and chard and other leafy green fanatic, but I almost always cook them first. It helps that my little garden produces industrial quantities of kale year round. The recipe in the photo sounds nice. I tried once to make buckwheat soba from scratch, but it did not go well. I am not giving up, though, just regrouping. Have a nice weekend!

  2. 2

    Lisa D (This Little Piggy) — March 2, 2012 @ 6:09 pm

    Interesting read – thanks Winnie. I had read about the high levels of oxalic acid in raw spinach and purslane but wondered how much you need to over-dose.
    I LOVE all veggies but I agree the trend is green smoothies is a little worrying. I have so many friends who’ve invested in Vitamixes and are giving their little ones green monster smoothies every day. It also seems a fad, better to eat veggies with every meal.

  3. 3

    Kathryn — March 2, 2012 @ 6:53 pm

    Thank you for another really interesting post – I tend to eat my greens cooked with the odd salad thrown in and I’ve stayed far away from the green smoothie trend so hopefully I’m not doing too badly but I have to admit that it’s more by luck than anything else and I hasn’t realised some of the concerns about eating large amounts of leafy greens. As always, your posts are a great education!

  4. 4

    Sabrina Modelle — March 2, 2012 @ 8:12 pm

    Dr. Winnie,
    How come you’re totally the best? I am a raw greens junkie, but try to eat them cooked too. You’re breaking my heart just a bit on the raw kale, but I’ll figure it out. Fabulous article.
    Thanks,
    Sabrina

  5. 5

    Dennis Murray — March 2, 2012 @ 10:10 pm

    More types of leafy greens was one of my revelations since September.

    I’ve been fine with variety in my salads when we eat out, but haven’t sought them out at home. After growing several varieties in our garden, arugala has become a regular addition to our salads. It’s a great compliment to sweeter flavors in fruit or vinegars.

    I decided to try the heavier leafy greens back then – kale, chard, collards, and mustard greens – all sauteed – and found them delicious with some bacon or cider vinegar as an accent and cooked in cast iron.

  6. 6

    Valeria Necchio — March 3, 2012 @ 2:12 am

    This is so informative! In Italy we tend to eat all of those greens cooked for some reason, it is a traditional thing and it is not questioned so much. I started to eat kale or spinach raw on occasions thinking that I was getting more nutrients, but apparently there are drawbacks to it. I do eat lettuce, radicchio, escarole and rocket raw, though. I don’t eat those every day, but anytime I eat them, it is in their raw form. Is that negative, too?
    Thank you so much for these articles, very very useful!

  7. 7

    Paula — March 3, 2012 @ 9:50 am

    As a person who has had an under-active thyroid for over twenty years, this was a very enlightening post. Thank you!

  8. 8

    Hallie @ Daily Bites — March 3, 2012 @ 10:57 am

    Thanks so much for linking to my post! :)

  9. 9

    fabiola — March 3, 2012 @ 2:05 pm

    Thank you so much for posting this. I love learning new things about what we eat and how it is best to eat them to provide the most amount of nutrition. This is awesome! I am a fan of balancing in all parts of life, so that is what I will take away from this, thank you!

  10. 10

    linda — March 4, 2012 @ 7:56 am

    Very informative, thank you. I didn’t see romaine on your list. I eat a salad everyday for lunch and the base usually starts with romaine and watercress. Have to say that I tried cooking collared greens and they were very bitter and no one liked them. Had better luck with kale. Love your website!

  11. 11

    Erin @ Texanerin Baking — March 4, 2012 @ 8:13 am

    That was really interesting! I ate kale for the first time a few hours ago. I sauteed it in olive oil and garlic and there was a lot of choking. It was just awful. My problem is that I don’t like any vegetables other than potatoes and corn (I know they don’t really count as veggies) but I’m trying hard to eat more. The thyroid thing is new to me and I only eat broccoli and cabbage raw, so thanks for that. :)

  12. 12

    Grace — March 5, 2012 @ 9:12 am

    I’m actually working on this but it is an uphill battle. I can serve collards any day and they will be well received, but all other greens I’m having to sneak into soups, sauces and casseroles. Hopefully familiarity will breed tolerance eventually, if not actual liking. I’ll keep trying.

  13. 13

    Jesse — March 5, 2012 @ 3:03 pm

    Love your blog and recipes… Just wanted to point out that raw cruciferous vegetables can only do damage when there is a concurrent lack of iodine present in the diet. Just a big raw veg fan and wanted to point that out. Thanks!

  14. 14

    You’re Not Paleo…and turkey burgers with roasted brussel sprouts and chipotle sweet potatoes | ugly food tastes better. — March 12, 2012 @ 6:31 pm

    [...] things, all you are going to do is make yourself crazy every time a new study comes out like this nonsense about how leafy greens will kill us [...]

  15. 15

    Jayne — March 23, 2012 @ 6:26 am

    So interesting! I’m disappointed to learn that it’s not good to eat too much raw spinach or cabbage! I particularly ate loads of raw spinach! Oh well a good excuse to try out making kimchi, something I’ve been meaning to do for ages!

  16. 16

    One Simple Change: Eat a Balanced Diet | Healthy Green Kitchen — May 25, 2012 @ 10:38 pm

    [...] in your diet; these are high in minerals such as calcium, magnesium, and iron. I’ve mentioned before that I’ve always heard it’s best not to eat large amounts of these greens raw. I know [...]

  17. 17

    One Simple Change: Some "Snippets" (And Home Dried Chile Peppers) | Healthy Green Kitchen — September 21, 2012 @ 10:18 pm

    [...] high-oxalic greens in a yogurt-based smoothie. I sort of mentioned these points in my post on leafy greens but I felt they were worth mentioning [...]

  18. 18

    One Simple Change: 5 Informational “Snippets” (And Home Dried Chile Peppers) | Easy And Healthy Meals — September 26, 2012 @ 1:15 pm

    [...] high-oxalic greens in a yogurt-based smoothie. I sort of mentioned these points in my post on leafy greens but I felt they were worth mentioning [...]

  19. 19

    Stephen — October 4, 2012 @ 12:29 pm

    If we want to live a happy and longer life, we should include the “green” in our diet. That is the common statement we could hear to most health experts. Almost all vegetable could do no harm for us, in fact they are beneficial for our health but it doesn’t mean we should only eat them to achieve a healthy living, we should consider other foods, and that is what we call a balance diet.

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