The Dangers of Green Smoothies (Can contain toxic levels of certain compounds)

By: Cat Ebeling, co-author of the best-sellers:  The Fat Burning KitchenThe Top 101 Foods that Fight Aging & The Diabetes Fix

Green smoothies and green juicing have taken the world by storm. Everywhere you look, there are green smoothie detoxes, and green juice powders, and green drink “cleanses”.

These green smoothies or green juices often contain a large amount of spinach, kale, chard, collards, arugula, or other greens.  Yes, we have heard our whole lives that we should be eating more greens, but the green juice/smoothie cleanse may have taken it a step too far. While a little may be good, too much is NOT GOOD.

As you have probably heard me say over and over again, “Eat REAL food”.  I have never been a huge fan of smoothies, shakes and juices. Real food is where it’s at.  I certainly don’t think our primal ancestors lugged a blender or juicer around during the day to blend up all those berries and greens they gathered. Nope, chewing is important, and it is necessary part of good digestion and good health.

Smoothies sound great, but since they are liquefied food, you generally end up consuming WAY more than you normally would if you were eating those things as solid food. What would fill a massive bowl as whole food, gets blended down into the size of a large drinking glass. There is often too much fruit, too much sugar, too many greens, too many carbohydrates, etc. All downed with a just a couple of gulps.  And as we’ll show you in a minute, there can also be TOO much of some problematic compounds in these green smoothies or green juices that you need to know.

So–how can a green smoothie be bad for me? It’s got everything good in it, right?blank

Yes, dark green leafy greens and cruciferous veggies can be powerfully healthy, and they contain a boatload of antioxidants like beta-carotene, lutein, and zeaxanthin and other fantastically healthy phytochemicals as well. They can help fight cancer, heart disease, diabetes, and obesity. These veggies also boost immunity by lowering inflammatory responses, reduce cell damage, and aid in digestive health too.

And yes, I know it sounds crazy for me to be cautioning anyone to watch out for overdosing on green vegetables, but the fact is, you CAN overdose on them, and many people are doing that without realizing it.

Spinach and other green leafy vegetables including chard, dandelion greens, kale, collards, beets, arugula and broccoli, all contain substances called oxalates. Oxalates bind to calcium and iron in the body and actually prevent the body from absorbing these important minerals. See more foods and oxalate content here.

What’s more, when oxalates bind with calcium they can create kidney stones, exacerbate painful gout, and cause other arthritic joint problems. Calcium oxalate is actually responsible for almost 80% of kidney stones. Oxalates can accumulate in the body and build up in the kidneys, causing serious problems, as was the case with this woman who ended up in the ER as a result of a green smoothie cleanse. Research shows that green juices and smoothies contain high levels of soluble oxalates and that drinking these green drinks too often can not only cause oxalate kidney stone formation, but even lead to renal failure.

People with certain inflammatory diseases including gout, arthritis, and even vulvodynia should avoid foods containing oxalates, because they can make those conditions much worse. Oxalates have been considered as playing a role in these diseases:

  • Thyroid disease
  • Vulvodynia
  • Calcium-oxalate Kidney Stones
  • Cystic Fibrosis
  • Sarcoidosis
  • Asthma
  • COPD
  • Autism

Excess oxalate can also lead to oxidative damage and the depletion of glutathione. Glutathione is one of the most powerful antioxidants in the body, and works to optimize liver function, helping to metabolize environmental toxins that enter the body.

Generally, most people can break down and process reasonable quantities of oxalate in the digestive system and it passes out of the body through the stool. However, those who have Crohn’s disease, IBD, intestinal permeability, poor fat digestion, celiac disease, inflammation, prolonged diarrhea and other digestive disorders may not be able to process oxalates out of the body as efficiently. Antibiotic use also eliminates the necessary bacteria that break down oxalates in the intestines, so they can harmlessly pass out of the body.

Many diet and health ‘specialists’ promote green smoothies or green juicing as a detox. And unfortunately,blank as is the case with smoothies and juices, you can over consume green leafy veggies, because you’re ingesting WAY more than you could if you had to chew them up and eat them as a whole food. And over consumption of even healthy foods like greens can actually bring on kidney failure, as in this case of a green detox gone bad.

According to this handy reference guide, a high oxalate intake is defined as consuming 250 mg oxalate per day. But a mere cup of raw spinach contains around 656 mg oxalate, and some people are using several cups of spinach and kale in these smoothies and juices, which is a massive quantity of oxalates. So, you can see how easy it is to consume too many oxalates in one glass of green smoothie or green juice!  Especially if you were doing a detox and having two or more green smoothies or juices a day.

Another issue with eating—or drinking—too many cruciferous vegetables like kale, collards, arugula, broccoli, cabbage and bok choy is that these vegetables can pick up a heavy metal mineral called thallium from the soil they are grown in. Thallium, for some reason, tends to concentrate in cruciferous vegetables, even if there is not much in the soil. This means if you happened to be eating an overabundance of cruciferous vegetables, you could be overloading your body with this toxic metal as well. Overdosing on thallium can cause strange symptoms like patchy skin issues, hair loss, arrhythmias, nausea, diarrhea, peripheral neuropathy, foggy thinking, digestive issues and more.

A molecular biologist, Ernie Hubbard, found similar symptoms amongst many of his health-conscious clients who were experiencing bizarre reactions that did not seem to fit any type of disease pattern. After a thorough investigation, he was able to trace their problems back to thallium toxicity from an over consumption of cruciferous vegetables.

There is one more issue with cruciferous vegetables. Cruciferous vegetables, which include the ever-popular ingredient, kale, contain compounds called glucosinolates, which inhibit iodine uptake by the thyroid. Iodine is a very necessary nutrient for thyroid health.

These goitrogens, as they are called, have been scientifically studied and are known to interfere with proper thyroid function. An overabundance of cruciferous vegetables (especially raw) in the diet can actually decrease thyroid hormone output, resulting in a hypothyroid situation. Hypothyroid symptoms include weight gain, hair loss, lack of energy, sleepiness, depression, anemia, and decreased immune function.

What Does this Mean — Avoid Greens Altogether?

Use organic veggies if you are making green smoothies—and don’t overdo it! As mentioned above, too many green smoothies can defeat the ‘detox’ part of a cleanse. Cut back or rotate the green leafy vegetables with high oxalate content to limit the oxalate levels you are taking in.

Opting to eat your greens and cruciferous veggies in their whole-food form is probably the best and healthiest option. You get the nutrient qualities of the greens without overdoing it and causing an overload of any other unwelcome ingredients. Chewing whole foods, as in a salad or side dish, is the best way to eat any food, not blended and masticated as juice or a smoothie.

Final Thoughts

Overdoing ANYTHING—even a good thing, can be bad, whether they are green smoothies, detox cleanses, juicing, etc. Green smoothies and green juices can contain too much thallium, oxalates, and goitrogens.

Smoothies of any type are a concentrated way to gulp down way too many calories, too much sugar, and too many other undesirable ingredients as well. A ‘detox’ diet of green smoothies or green juices may actually overload your body with toxic substances. Smoothies in any form are a concentrated way to drink down a massive amount of calories, and as you can see, a whole lot of other stuff too.

Veggies can be an awesome thing to have in your diet, and I still recommend you include a good portion of multicolored vegetables in your diet—as whole foods.

While you cannot avoid oxalates in green leafy vegetables, be sure to choose organic vegetables to reduce the amount of toxic metals such as thallium, and toxic residues. Conventionally grown spinach and kale both contain high amounts of toxic pesticide residues.

Certain types of beneficial bacteria in the gut actually help to break down and process oxalates in food. Supplementing with probiotics and fermented foods that contain Lactobacillus rhamnosus, Bifidobacterium animalis will help to break down and prevent oxalate buildup in the body.

Just remember, too much of any kind of good thing can go bad.

[Mike’s note:  Although some people seem to do fine eating leafy greens, I personally discovered about 3 years ago that leafy greens did NOT agree with my body, and was harming my digestion.  I probably ate a leafy green salad every night for 15 years and never questioned it, because everybody tells you to “eat more veggies”, especially leafy greens.  

However, whenever I tested eliminating the salad and focusing my meals more on meat, starch, avocado, and cooked veggies, my digestion would dramatically improve, I would have no bloating, and would feel better overall.  My bowel movement the next morning would be much better too when avoiding leafy greens.  Then, I would test adding leafy green salads back into my daily meals, and my digestion would suffer again…including bloating as well as a bowel movement the next morning that was excessively loose.  So I FULLY removed all leafy greens from my diet 3 years ago, and it was the best thing I’ve ever done for my digestion.  The more I talked to other people, friends, Naturopathic Doctors, etc, I kept finding time and time again that there are a lot of people that don’t digest leafy greens well at all, and do better with cooked veggies and roots like carrots, beets, and sweet potatoes.  As a nutritionist, I can say with 100% certainty that there is NOTHING “essential” about eating leafy greens… we can get every single nutrient we need from other foods like non-leafy veggies, fruits, nuts, meats, eggs, etc]


About The Watchdog

Mike Geary has been a Certified Nutrition Specialist and Certified Personal Trainer for over 15 years now. He has been studying nutrition and exercise for almost 25 years, ever since being a young teenager. Mike is originally from Pennsylvania, but has fallen in love with mountain life and now resides in the picturesque mountains of Utah. Mike is an avid adventurist and when he’s not spending his time skiing, mountain biking, hiking, or paddleboarding on the lake, he has enjoyed skydiving, whitewater rafting, piloting an Italian fighter plane (seriously), scuba diving, heli-skiing, and traveling all around the world, enjoying learning about different cultures. At the age of 40, Mike now feels healthier, stronger, and more energetic than when he was 20... All because of a healthy lifestyle and great nutrition!

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  1. Love the article! When i started juicing , a couple of blood vessels in my hand popped and i felt awful and weak. My doctor told me i had juiced too many varieties and started with way too much way too fast. I stopped juicing and started making smoothies instead. I have a very sensitive body so i’m still learning what works and what doesnt. I must say, your article really helped me to understand why juicing just doesnt work for me. Thank you! I was close to ending up in the hospital and all because of juicing.

    • Romaine Lettuce is very low in oxalates and a good source of vitamin A, and sort of for folate and vitamin C. It has several amino acids too. Can’t go wrong with salads with Romaine lettuce everyday.

      • Good information and good discussion! Nothing wrong with an occasional smoothie in my book. But another thing to consider about relying on smoothies, is the likelihood that many antioxidants have been destroyed in the blending. And chewing doesn’t happen, so the saliva isn’t produced.
        Like the author, I can’t consume much in the way of raw vegetables. People with Leaky Gut, SIBO, do better with lightly cooked produce.

        BTW I’m ok with a writer promoting a product- he freely shared a lot of information here.

    • Every Dr. that I have talked to about juicing and making smoothies also recommend lemon water and apple cider vinegar to cleanse the kidneys and liver and help with digestion. They also recommend one all natural organic smoothie homemade containing green vegetables avocados or other similar items such as with ice, almond milk, with no added powders and no fruit because the fruit condenses to sugar. So wow I see this post as that information I don’t think it has all the needed information in it like instead of telling people to stop maybe telling them to reduce the amount that they do daily and also how to cleanse the kidneys and liver .

    • Does nettle contain oxalates or thallium?

  2. I am not sure if I agree entirely with this article as I do know many people who blend kale and sea salt, like a type of Sauerkraut but ‘drunk’ whilst the enzymes are still very much alive. They have ‘cured’ themselves of Crohn’s disease by doing this and many others have reported favourable health conditions. The problem is that the antibiotics taken do indeed destroy the good and bad bacteria in the digestive system, once this is achieved the nutrients that one is consuming are not fully realised by the body.
    We need to go back to our roots and realise the gut/immune pathway, as with everything in our body as is with the universe, they are all interlinked and should not be treated as separate systems. It is important that even with juicing to ‘chew’ the food in your mouth for awhile, get the saliva fully mixed in. Take time to enjoy your food.

  3. My husband actually passed a kidney stone at a concert after having had a daily green smoothy with kale and spinach….
    The Dr. told him to go light on/ eliminate the greens! Too many almonds can do the same thing…..

  4. never understood the smoothie craze, we were not designed to ingest only/mostly liquid food, but our fast paced society of course welcomes “eating” your veggies in liquid form, no need to chew (though you should chew your liquids). Juicing and liquid food should not be the norm but used for times of illness, fasting, detoxing, in short not for a lengthy meal replacement strategy. We tend to overdo every thing…. either or, not finding a balanced middle ground. BUT that is just MHO.

  5. The article lumps kale with spinach as harmful because of too much oxalates, yet the linked table of oxalate content shows spinach to be hundreds of times as high as kale! Kale ranks quite low.

    As for chewing, the machine chews it up far better than I can, making more nutrients available, which is important since modern farming has depleted out soil so badly, and on the average, food grown today only has half the nutrition of what we had 50-75 years ago.

    As for iodine uptake, you ought to be supplementing iodine anyway. The tiny bit that’s in iodized salt is woefully inadequate, according to Dr. Brownstein and other experts in that field.

  6. Part of my decades long success consuming smoothies is that I quickly realized that putting fruit in a smoothie twice a day amounted to a lot of sugar. I now add only locally available fruit when it’s in season, the same sugar consumption level of our ancestors – except for those rare seasonal honey finds. By the time I learned to cut back on fruit I also learned about the pitfalls of oxalates, phytates and lectins. Since I went green about a decade ago I never put raw spinach or chard, the two culprits with the highest levels of oxalates, in my smoothies. Lacinato kale is actually quite low in antinutrients, so I add it raw occasionally, especialy the younger leaves. If I do eat other cruciferous vegetables I steam them lightly to remove the most of the antinutrients before adding them to my smoothie.
    True enough, our ancestors didn’t have blenders, nor do I. I use an immersible wand, it doesn’t blend as fine so my smoothies remain chewy. For those of us with digestive issues, predigesting food in smoothies is a boon.
    Our ancestors did, however, grind many things together and cook them. I can walk a short distance from my farm and find holes in rock formations where ancient tribes used hardwood poles to grind all sorts of food products together to prepare as soup. Soup, which has been eaten for countless millennia, is just a hot smoothie.

  7. The kale/thallium is very real! I hadn’t heard of thallium, but boy did I find out. I got very ill from an MRI contrast injection. I couldn’t walk, thus could barely cook. I’m a health coach, and thought the greens would help me heal. I was eating frozen organic kale and broccoli daily for a month. Well, when we tested me for the gadolinium (MRI contrast) my doc has me come in to call the lab with her. My thallium was off the charts—over 3 times the safe amount. The lab asked if I’d been eating a lot of kale! I was so incredibly sick—hair coming out in clumps, I was basically killing my self. And the only med that chelates it was $900 for ONE MONTH. It’s for radiation poisoning. So yeah it was the worst time of my life. Please vary your foods!! And the CA greens are the most contaminated. Do your research please. Don’t suffer like I did. I make sure my clients work with a variety, preferably local produce. I hope my story helps someone else.

    • Hi Susan,

      After having green smoothies for almost 3years I’m having extreme hair loss, joint pain, and digestive issues which I never had prior to green smoothies. What chelates did you take? Were you cured? I would like to know more of your journey. Please respond.

      Thank you.

      • Chelate the cheap and easy way and it is very very safe as well: take liquid iodine extract from sea kelp in combination with a product that contains chlorella. Work up from one drop to five the first week of iodine and from one droppersful up to two and keep at it for six months to one year. It will pull out and isolate then dump to your kidneys for safe excretion all types of contaminates and heavy metals, including Thallium.

        • Leslie what dose of chlorella along with the iodine to chelate the heavy metals which seem to be in so many of our foods. Any brand of iodine to use or brands to avoid? Have heard of prople rubbing it into their skin

  8. Always go to the end of the article, in most cases the writer is promoting his own brand. Whatever he is demeaning is also contained in his brand. People do your research. Nothing is one size fits all. Just because someone landed in the ER after drinking green juices or smoothies does not mean that is the actual cause. There could be pre-existing conditions or triggers.

    • In this case, maybe the thallium was in the contrast dye? Maybe the kale dislodged it from his or her tissues, but couldn’t bind with it, so basically free heavy metals in t he blood stream. No es bueno. Incomplete chelation is my guess.

  9. What about cooked spinach, cooked broccoli, etc … does cooking the cruciferous vegetables lower the amount of oxalates in them?

  10. Patriot power greens is high in oxalates. People dont be deceived. Do your research. Look at the ingredients. The first high oxalates is beet juice powder. Beets have 82mg of oxalates per 1/2 cup. Has the product been tested. Do you know how many oxalates are in a serving?

  11. I 100% agree with this article. I also have eliminated all green raw vegetables from my diet many years ago and in the last 20 years I only had one 3 day cold. I eat the whole rainbow but mainly fruits, nuts and seeds. I drink a detox tea made with curcumen, ginger, jamaica, and a blend of green and other teas and herbs to help the liver detox. Also I fast once a month for several days giving me coffee enemas during this days. I think that’s the best detox together with activated carbon and half a liter of water first in the morning. We live in a toxic world and detox is very important to stay healthy. The last thing that will detox your body is greens full of toxins. Great article. The world will thank you. With love and peace. Jörn Malek

  12. Juicing has been used to heal cancer, I’d give it a try would I get cancer.
    People susceptible to bladder stones/crystals usually have the common sense not to go too heavy on oxalate-rich foods.

  13. What works for one may not work for another. Do not take this as something you should follow, only as a guide to learning about the path of finding out your own particular nutritional needs. Just because some facts were included does not mean that this was scientifically factual.

  14. I would be interested to hear Dr Katherine Reid’s response to this as she claims to have cured her daughters autism using a glutamate exclusion diet and eating a diet 70% veg including a green smoothie everyday with as many veg as you can throw in.

    • That smoothie recipe you mentioned gave me a gout attack….

    • If she believes vaccines triggered the Autism, then she is probably cheating heavily at the same time. (The childhood vaccine schedule introduces mercury and aluminum and many other toxic compounds which have never been tested on children or pregnant women past the blood brain barrier gut filtration by dumping toxic chemicals %685 times the toxic limit established by the EPA – and that is in a single pre-natal flu shot!) Boytom line: She’d probably have faster results if she didn’t green juice her kid.

  15. Mike. Thanks for this information! Can you provide an expanded list of fruits and veggies or whatever you eat to help with digestion issues. Thanks

  16. I buy a powdered green juice and it comes with its own little scooper so I cannot overdose on it as you suggest. Since I’ve been taking it every day my nails have started growing again, my hair is thicker and healthier and I’m not starving for sweets all day. I’ve also lost 10 lbs in 2 months. I am very happy with the results so I see no need to fix something that isn’t broken but is better than it has been in years.

  17. I’m a carnivore! No fiber no starch no carbohydrates. High fat and lots of organ meats. If you follow the food pyramid and do the things (such as regular inoculations for you and your family) you will be quite sick. Profalaxis (masks which tight seal on trains and elevators, plus hand sanitizer), proper rest and high quality whole foods, sanitation (flush toilets and garbage hauling) and regular supplementation with A, D maybe E and minerals such as magnesium and calcium are all you need. Let your kids get the childhood diseases (but only wild, never vaccine mutated strains or shed strains) confers lifelong immunity and protection. Don’t believe the lies. Americans are unhealthy following the guidelines (worst health on the developed world by far!)

  18. We are all different. Your article and the comments help to show us that extremes of even healthy foods can be detrimental to a person’s health. The article is a bit extreme, but something to consider as a balance. Thank you for this interesting information. This diet may be the answer for many people, and a wake-up call for many more.

  19. Nice and informative post hope will share more again like that.

  20. Following successful brain tumor removal surgery I have been getting periodic MRI scans for review by my oncology team. Have always been suspicious about the “contrast” which hasn’t seemed to be in any way destructive (so far). They have also had me on chemo by pill which I’m very leery of and which they have determined (thankfully) I can remove from my current recovery regime.

    I can say authoritatively to anyone who is going to have a run in with cancer your best bet going in is a healthy body and nutritional lifestyle engaging exercise and a good night’s sleep. My oncologist says he has 4 living patients he is treating for stage four glioblastoma in his 20 years of practice and I’m #5.

  21. The kinked table of oxalate content of leafy vegetables is pretty useless because leafs in a measuring container contain variable amounts of air. I suggest where I can find (example)
    Kale 100 g 20 mg USDA 1984
    Collards 100 g 450 mg USDA 1984

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