Why Most Green Smoothies Aren’t Healthy- The Inside Scoop on Oxalates

I may receive a commission if you purchase through links in this post. I am not a doctor; please consult your practitioner before changing your supplement or healthcare regimen.

This article is a bit personal, if you perhaps love green smoothies. Many of us started drinking green smoothies in an effort to get healthier, to heal some health condition or because we’re “crunchy” and love healthy tasting foods. But daily green smoothies or green juicing are counter-productive and ironic, for those who are seeking optimum health or healing. Many raw leafy green vegetables need to have their oxalates reduced through fermentation or cooking. Some leafy veggies, like most foods, should be eaten in moderation, purposely choosing low-oxalate options and rotating different varieties.


Oxalates are organic acids produced my humans, animals and plants.  In plants, the leaves always have the greatest concentrationWhy Most Green Smoothies Aren't Healthy- photo of kale of the oxalates.

Kale has perhaps been over-vilified regarding oxalates. It is actually low in oxalates, although the amount contained in any vegetable can vary depending on the soil and the season. Yet I am still an advocate for steaming or cooking kale, not eating it raw. Or ferment it!  Why? Kale and broccoli are both great examples of vegetables that may not be high in oxalates; but they are still hard to digest raw!

As Donna Gates of The Body Ecology Diet says,

…all members of the cruciferous family…in their raw state are considered to be “cooling” and suppressing to your thyroid.

Green smoothies do not need to be abandoned altogether.

We have gotten around the issue of oxalates in green smoothies at our little frozen kefir and green smoothie cart in Eugene, OR. How? Our green smoothies do not contain spinach, chard or other high-oxalate or cruciferous produce.We green-ify with spirulina (find it here) and fresh basil (or other herbs)! Delicious in smoothies and low in oxalates! Wheat grass is also a safe green juice. We use dehydrated organic wheat grass powder for convenience.

Many green smoothie lovers use smoothies as a meal replacement, especially for breakfast. But let’s face it; the traditional farmer’s breakfast has it right: eggs, sausage and sourdough are great ways to start the day. Going back further in history, soups and stews and soaked porridges or breads were nourishing breakfasts, and still are. Smoothies are fun foods for occasionally. (Those who can’t have eggs or grains still have plenty of options with grass-fed meats, stews, cultured foods, cooked veggies, raw produce, [the right kinds in moderation], raw dairy, coconut yogurt etc.)

But changing habits can be challenging. I acknowledge that many Americans, especially, have a hard time switching away from cereals and smoothies. They’re easy; we thought they were healthy, even in excess; and they taste good.

Why Most Green Smoothies Aren't Healthy~ Learn about oxalates, cruciferous veggies and how to make your green smoothies healthy! #greensmoothie #healthy #autoimmune #oxalate #cruciferous #ferment #cookedfood #traditional #paleo


What happens to the body when it’s inundated with too many oxalates?

Kidney stones are the most common outcome, especially for those in higher risk groups:

  • Those with candida overgrowth
  • 10-20% of the population who are genetically predisposed to producing excess oxalates themselves
  • Those who have Asian and Caucasian heritage
  • Those who are obese
  • There are many health conditions that make kidney stones more likely to form- Crohn’s disease and ulcerative colitis, IBS, high blood pressure, and hyperparathyroidism, to name a few

The problems that ensue, in addition to causing kidney stones, include these conditions:

  • Musculoskeletal problems
  • Autism
  • Yeast infections and general yeast overgrowth
  • Crystallization anywhere in the body, wreaking havoc in vital organs such as the heart and thyroid, causing permanent damage

Why Most Green Smoothies Aren't Healthy- photo of spinachWHAT TO EAT

Dr. William Shaw, an expert in diet and its relation to autism, ADD and Down Syndrome recommends low oxalate diets with the following supplements which compete in the gut for absorption, deterring crystallization: probiotics, the citrate forms of calcium and magnesium, vitamin C (which he vindicates in its role of contributing toward kidney stones), vitamin B6 and arginine.

I’ve been influenced by Weston A. Price and advocate for eating a high-fat diet, which aids the body in mineral assimilation. This mindset is interesting considering that most green smoothies are non or low-fat. A great option is to add a giant scoop of probiotic sour cream or homemade high-fat yogurt to your weekly smoothie. High-fat coconut milk or coconut milk yogurt work well too, for non-dairy diets. Lately, we love adding MCT oil (find it here).

If you are suffering from kidney stones there are many suggestions to be found online. But perhaps the most important thing to keep in mind is to supplement with foods, not with supplements, unless under the care of an expert (naturopathic or functional) physician. While it’s true that increasing K2 and B6, as well as many other nutrients, can aid in dissolving mineral build-up, these nutrients must be with their co-factors for proper assimilation and in the right ratio to other nutrients.

Here are some foods and one supplement (safe and not easily found in food) that will aid in kidney stone elimination and in deterrence of crystallization in general:

  • Find K2 in brie and gouda, butter, fermented cod liver oil, fermented veggies, organ meat, and grass-fed eggs. These foods all provide K2 in the right ratio with magnesium, vitamin D, vitamin A and calcium.
  • Magnesium (this is the one I like) helps balance calcium absorption properly so it won’t calcify.
  • Taking 2 T. of olive oil and lemon juice mixed together 4 times a day is recommended by many herbalists. Lemon juice provides potassium citrate as well as vitamin C.
  • Thyme, knotgrass, and juniper teas are all recommended.
  • Use high-fat preparations when you do eat greens. Butter, ghee and coconut oil, as well as traditional fats like tallow, help nutrients like calcium to better assimilate.
  • Consider chanca piedra, also known as Stone Breaker. Ehow says of it, “With a name that literally means “break stone,” this beneficial herb has been used for centuries to break up kidney and gall stones…”  It truly has a wonderful reputation and some great success stories.

What exactly not to eat to deter crystallization of oxalates?

  • Cut out foods like peanuts, chocolate, spinach, parsley, beet greens, collards, rhubarb, black tea, soda, and citrus fruits, which are all high in oxalates. Soy, grains, nuts and seeds, berries, kiwi and grapes are also high. Here’s a more exhaustive list to use as a guideline.
  • The cooking liquid you use to steam, boil or blanch leafy greens should be discarded.
  • Raw spinach salads have been en vogue for a couple decades. They should be wilted with hot bacon fat, for a gourmet dressing, steamed or sauteed first, or not eaten at all.
  • Cut out excess fructose. See my smoothie ideas below, all of which are low-fructose!

Those of you who once loved green smoothies, as I did, what do you put in your smoothies now? I like frozen cooked carrots with fresh mint and grass-fed cream! Find my favorite Carrot “Milkshake” here, with ginger and turmeric. There are so many creative new options! At our smoothie food cart the most popular two (green) smoothies are Watermelon-Basil made with Vanilla Frozen Kefir and Blueberry-Spirulina with Cultured Cream! 🙂 You can also steam greens and put them into your smoothie cooked; or freeze the cooked greens in little mounds on parchment-lined cookie sheets to throw into smoothies as needed (or fill ice cube trays).

Share with me what you do!

There are so many creative new options! At our smoothie food cart the most popular two smoothies are Watermelon-Basil made with Vanilla Frozen Kefir and Blueberry-Spirulina with Cultured Cream! :)

Vanilla Jill’s Watermelon-Basil Milkshake (an old photo!)

What safe green ingredients most appeal to you: cooked greens, fresh herbs, spirulina?…

Comments 43

    1. Thanks, Mani! We’ve had fun creating our menus and they are really lovely. The watermelon one really explodes with flavor in your mouth; and the high-fat blueberry one is my favorite. 🙂

  1. my mind is being BLOWN right now. My whole green smoothie world has been turned upside down. GAH!!! So thankful for your wisdom and research Megan!!

  2. I am feeling like Holly, too! Oh some research in my future. I love my green smoothies. Sniff, sniff. I have seen such amazing results with me health since starting them. Seems like everything you think is good for you can backfire. Thank you Megan for this eye opener and your hard work.

    1. We are so young in our understanding of nutrition, since we lost our wisdom gained from ancestors and now bust out on our own without a foundation…until we learn the hard way or look to the past again. Hugs and so sorry and yes, you can still find a happy medium with certain fresh herbs, spirulina and steamed greens etc. It’s still a blow; and I went through it too. I used to make raw parsley and cranberry smoothies and thought they were the best. I love weird strong things. Boo hoo with you and I hope you find new favorites!!! <3

      1. so you think raw parsley is not good either? i would love parsley and cranberries with stevia in a raw eggs smoothie! i used to put 1/2 a bunch of parsley in my smoothies. i would rotate greens but have them 5-6 dys a week. i used a ton of greens in each too. n usually had1/3 of a raw beet also n ginger too or sumtimes did a chocolate one. i wanted to get as much greens in the smoothie as i could. i would then blend in water for 3 min straight to liquefy. i would add shredded coconut too to have my own homemade coconut milk. added coconut oil or cream also. called them my fatty leafy drinks lol
        i considered cooking the grns first at one point but i knew i d never do it on a daily basis and they were my breakfast almost always. i dont even buy bunches of grns, only chopped, washed, bagged grns brcuz otherwise i ll never eat greens…i just wont. and we eat greens daily as i try to do wahls protocol with her reqt of 6 cups raw along with 6 cups raw cruciferous which are generally grns too. salads count! 🙂

        1. Yes, I believe that all of the raw greens are counterproductive, not counting salad greens, which are fine and wonderful for eating raw. I can relate and understand; yes, I used to love my raw parsley smoothies. Best to cook your bagged greens and then add them in. Also, raw egg YOLKS are great. But raw egg whites are hard to digest~ perhaps one more thing to keep in mind.

  3. I have a kefir smoothie every morning. 400 mls kefir made with raw cows milk. 2 egg yolks, 2 kiwifruit, 1 Tbs diatamacious earth, 1 Tbs Maca, 2 tsp fermented codliver oil/ butter oil. And if I am planning on a late lunch i also add 1/2 a banana and 1 Tbs of coconut oil.

      1. What if first we steamed all our leafy greens to lower the oxalates and then freeze them? N then use them for your green/ fruit smothies? Would this be better n considered a more nutritional way for our bodies to absorb them. ? Thanks.

        1. Yes, this is a perfect solution! 🙂 I also recommend not overdoing green smoothies, or using low-oxalate greens- like fresh basil, wheatgrass and spirulina. It’s a great idea to rotate the kinds of smoothies you make.

  4. I’m enjoying reading through your posts. Thanks so much for sharing! I’m always looking for new ideas for our GAPS Diet (even though I have two recipe boxes stuffed full now 😉 ) and these smoothie recipes look great! I look forward to reading through your recipes and finding favorites to share with my GAPS clients.

    Thank you!

  5. Can u steam your greens first, freeze them n then use in your smoothy ? This would lower the oxilates n still be nutritious im assumimg.

    1. Yes, this is a perfect solution! 🙂 I also recommend not overdoing green smoothies, or using low-oxalate greens- like fresh basil, wheatgrass and spirulina. It’s a great idea to rotate the kinds of smoothies you make.

    2. I do not think that streaming them and freezing them woudl actually affect oxalate levels. Bioling yes may lower but not steam or ice. Oxalates are very stable.

    1. I personally enjoy incorporating barley grass into my smoothies, occasionally. It’s a definite super food. From what I can find I believe it to be low in oxalates, but have found less evidence than I would prefer to be sure. My favorite source for nutritional information is sometimes what I learn from the foods they feed racehorses! Oxalates bother horses too; and the lists of high-oxalate grasses to avoid feeding one’s horse does NOT include barley grass. It is never on the human lists either. But I haven’t found a chart or article that tells how much it DOES have. So I assume it is low; but I can’t yet know for sure. Thanks for asking, great question. 🙂

  6. Megan, If I order the “stone breaker” is there a recommended way to take it as prevention now that I am stone free? I will wait btw…till healed:)

    1. Yes, I really like the tea option; but the tincture is also great, depending on which one is more sustainable on a daily basis with your lifestyle and personal preference. There is strong historical use of both to stay stone free. Either Chanca Piedra Herbal Tea – Stone Breaker or Herb Pharm Stone Breaker Compound Mineral Supplement, 1 Ounce, both available from Amazon. Hope that one of them is highly effective for you, for a stone-free life, from here on!

  7. I buy big bunches of greens like spinach, kale, chard, and dandelion and blanch them as soon as I can so they are as fresh as possible. Two minutes in boiling water then plunged in ice water for most greens. Then puree them in the blender with a little water and freeze in icecube trays! I just add 2-3 cubes to my smoothies, which are always made with FULL FAT PLAIN yogurt. I get the vitamins and minerals from the greens while reducing the oxalates, the healthy fats from the yogurt, and don’t feel the need to consume huge bunches of greens at once like people often do with juicing.

  8. I’ve been searching and searching but cannot find any mention online of how much oxalates are in wheat grass powder. Do you happen to have such a reference? Thanks, appreciate your time!

  9. This information is so helpful!!! As much as I love them, raw greens have never been good for my digestion and body. They’re so much better gently cooked with a healthy fat. Thank you for sharing this important info.

  10. This is very interesting. Ever since I learned about oxalates, I’ve been wondering about green smoothies and have scaled back in making them. This is super comprehensive and educational! Excellent article!

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  11. I’ve never been on the green smoothie bandwagon. I prefer fruit smoothies as a dessert, or other veggies like squash, beets, celery and carrots in my smoothies. 🙂 I was pretty bummed about my salads, though, because I love adding spinach, kale, and other greens to them! Good thing they’re tasty sautéed, too. 😉

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      I hear ya on the salads thing. Now I do love putting lettuce underneath (like romaine or butter lettuce) and sauteed greens on top with all the other salad fixings. That’s kind of a compromise and tastes great. 🙂

  12. I’m not going to lie, I kind of want to cry a bit lol Mainly because we eat a ton of green smoothies and I am not convinced my girls are unhealthy and will get kidney stones- so deep breath haha I started steaming my spinach this week so we can rock that and I do alternate between chlorella and spirulina so yay on that front. Thanks for all the great info!

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      Good for you Shelby!!! YAY! That’s awesome! Once you start new steps they become the usual pattern! I’m glad you’re honest. It IS disappointing at first! I felt the same way! xo and xo! 😉

  13. Just keep sharing this! People aren’t going to believe you, or they’re going to say you’re alarmist or whatever. But just keep on sharing. I wish everyone would take this info seriously.

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      Aw, that’s lovely. Thanks, Lindsey! This truth is certainly not met with enthusiasm by most people. I appreciate your encouragement. There will always be people ready to hear it at different stages of their lives, just like we both were.

  14. High fat hey! Did that already. Now my liver and gallbladder is stuffed!

    No berries and fructose aswell. Hmmm. Dr Robert Morse claims to heal MS and cancer and everything really with these, herbs and glandulars.

    I was just on another website which believes salt causes calcium levels to rise in urine and therefore contribute to kidney stones. I have had a very high salt diet and have kidney stones. Wondering if this is the cause of these stones. I also drank tap water most of my life….recently learnt tap water contains inorganic minerals i.e. rocks like the lime scale in your kettle….and thinking this may have contributed to their inital development…so now if i have beetroot juice with high oxalate….i get kidney pain….aggravation of the stones because apparently oxalate binds to calcium of the existing stone.

    Distilled water removes these inorganic minerals….instead we are supposed to get our minerals from fruit and veg which contain organic minerals that we can actually digest/utilise.

    Im on dr morses diet ….all fruit…but all the acids being pulled from my lymphatic system are being buffered by calcium being pulled from my connective tissue so looking ugly…wrinkles…but apparently you gotta look ugly before you look pretty. I apparently can do green juices to help but risk aggravating the kidney stones. Not sure what to do because i dont really believe in cooked food. Maybe i should ferment the kale and spinach. I’ll try barley grass and basil as per suggestions here too. Thanks.

    Also…i wonder if soaking spinach in lemon juice will elimibate oxalic acid…then you could keep it raw for enzyme benefits…this way you can remove pesticide at the same time.????

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      Not in my opinion, Mihir. No raw kale is best. Instead: spirulina, chlorella, wheat grass are all good. Thanks for the questions. 🙂

  15. Also, in general are the all in one vegan powders healthy? Cause I do see spinach being used in them (possibly in small amounts but still worth thinking about)

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      Hi Mihir, in general vegan powders aren’t healthy. First of all, they often are legume-based, like pea powder for example (or soy), which is hard to digest or assimilate and can be taxing on the digestive system. The other concerning factor is either the lack of fat in them or the wrong ratio of omega 3s to 6s. If we were to look at separate brands we could talk about the individual ingredients.

      1. Thanks for the prompt responses! I was just concerned cause I like healthy stuff in general.

        The specific powder Im using right now is Vega. Use it for my morning meal. I have a whey protein powder post workout in the evening.

        As for your recommendations of Spirulina etc. Is Spirulina ok for daily use alongisde the following: Wheatgrass, Baobab, Gelatinized Maca, Goji Berry, maybe Acai Berry and Chia seeds?

        AKA (Is it possible to overdose on the nutrition with all these in the normal recommended amounts if had together daily?)

        Maybe Macha or Red Tea

        My concern with Spirulina is the fact that it needs to be prepared super safe and Chlorella has a bunch of unnecessary stomach related side effects which make it seem like Chlorella is only good for a 2 week plan while Spirulina ‘seems’ ok for daily intake.

        My shake looks like this atm: 1 cup almond milk, 1 scoop Vega all in one, 2 tbsp peanut butter, 2 tbsp avocado oil, 3 tbsp frozen fruit mix (strawberry, raspberries, blueberry, blackberry), 3/4 cup greek yogurt, 1 handful of kale

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          Hi Mihir, I would ask your practitioner to be sure. Typically, assuming the spirulina is sourced well, it is considered a safe, long term, daily supplement. I am careful personally to not overdo almonds or peanuts. Almonds are high in omega-6s and peanuts have mold, unfortunately; and they’re a legume, so high in lectins, which can be hard on the gut. I’m sorry- so many downers! Obviously, as we’ve discussed, no raw kale. 🙂

  16. Just passed a kidney stone…ouch. no more oxalates for me. Funny thing is I knew about the dangers and thought I was eating in moderation, they can really add up when they are small amounts spread out in different foods. I did kale and collards in smoothies thinking its ok because they are relatively low, and I was eating with fats and nut milk to “neutralize” the oxalates. (Not sure if that is real science or just a youtube thing…) I even have a chart of oxalate content in foods and still managed to form a kidnesy stone! I have been doing low fodmaps and as a result eating tons of meat and not much carbs…thinking that has to be a factor? I have no idea what I am supposed to eat to not get IBS, inflammation, low or high blood sugar, and now kidneys stones. I have to avoid: fodmaps, excess protein, resistant starches, acidic foods, dairy, nightshade family, chenopod family, etc… so what then, foodpaste? I cant find any info on turmeric and ginger, do you know if they are high oxalate foods? Thanks for making the article concise and packed with useful info, I am getting right on the suggested foods and bought some chanca piedra…hoping this was a one time thing!

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