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Green smoothies are all the rage these days. Many people are drinking them every day or at least several times a week in an attempt to get healthy and “alkalize” the body.
Whenever I visit the cafe of my local healthfood store, there are usually several people in gym clothes lined up to order a green smoothie to sip after their workout.
Green smoothies are made by blending large amounts of raw leafy green vegetables with fruit to soften and sweeten the taste. Typical vegetables included in green smoothies are cruciferous vegetables like kale, broccoli, collard greens, maca (usually as a supplemental powder) as well as others like spinach, swiss chard, celery, and parsley.
Is the green smoothie fad a truly healthy habit over the long term? Or, could regular consumption of these seemingly healthy drinks contribute to serious health problems over time?
Raw Leafy Greens Contain High Oxalate Levels
Frequent consumption of large quantities of raw, leafy green vegetables blended up as green smoothies can be deceiving at first. This is because green drinks facilitate an initial detoxification process that makes a person feel great. This is especially true when coming off a highly processed, nutrient poor diet.
While very nutritious, the vegetables used in green smoothies are almost without exception high oxalate foods. Over time, a high oxalate diet can contribute to some very serious health problems particularly if you are one of the 20% of people (1 in 5) that have a genetic tendency to produce oxalates or if you suffer from candida or other fungal challenge. In those cases, a high oxalate diet can deal a devastating blow to health.
Oxalate Toxicity Not a New Problem
The effects of oxalate toxicity have plagued humankind since ancient times. For example, scientists discovered an oxalate kidney stone about the size of a golf ball in a 2000 year old mummy from Chile using x-ray analysis.
Build-up of shards of oxalate crystals can occur almost anywhere in the body. Whatever tissue contains them, pain or worse is the result.
75-90% of kidney stones are oxalate related with 10-15% of Americans afflicted at some point during their lives. As the star shaped crystalline stones pass from the kidney, they cause pressure and pain in the bladder and urethra and can actually tear up the walls of the urinary tract.
Oxalate Stones from Excessive Green Smoothies
Oxalate stones can show up in any body tissue including the brain and even the heart.
Crystals comprised of oxalates resemble shards of glass. They can become lodged in the heart causing tiny tears and damage to this vital muscle. With every single contraction, more damage is caused as the heart pumps life giving blood to the rest of the body.
Oxalate crystals which end up in the thyroid can cause thyroid disease by damaging thyroid tissue.
A frequent location for oxalates to end up is skeletal muscle which will cause pain with even normal movement and make exercise nearly impossible. Dr. William Shaw, Director of The Great Plains Laboratory for Health, Nutrition and Metabolism who has studied oxalates extensively, is convinced that oxalate toxicity is a factor in fibromyalgia the pain of which can absolutely devastate a person’s life (1).
Vulvodynia – Painful Sex
Cases of women experiencing painful sex are on the rise with oxalates a possible culprit.
Vulvodynia is a condition causing pain in and around the vagina. It is linked to oxalates deposited in this delicate reproductive tissue. Oxalate crystals are very acidic and they cause irritation, burning, and stinging sensations for affected women. An accompanying feeling of rawness is typically experienced during sexual relations.
Oxalates Are Fungal in Origin
A surprising finding is that oxalates are produced in large amounts by fungus. Large stones have been found in the sinuses and lungs of people suffering from systemic fungal infections such as candida or Aspergillus.
Therefore, anyone who suffers from any sort of candida overgrowth or other fungal challenge like fungus nails or dandruff would be wise to be very concerned about oxalate intake via the diet.
Consumption of green smoothies would not in any way contribute to improvement of health in these situations. The majority of people today suffer from gut imbalance and candida (yeast) issues caused by antibiotic and prescription drug use including the Pill. This renders a high oxalate diet which includes frequent green smoothies an unwise practice for virtually everyone.
Does Cooking Destroy Oxalates?
What about cooking the greens first? Would this reduce the risk of oxalate overload and make consuming greens safer?
Not really, because oxalates are extremely stable. While cooking high oxalate foods and discarding the cooking water does reduce the level of anti-nutrients, it remains quite high.
Green smoothies are usually consumed frequently by those who swear by them. As such, a light steaming of the veggies first would not make a significant difference over the long term if they are consumed regularly. If you consume green smoothies only occasionally, however, a light steaming is a good idea. This practice adds a degree of safety to the process. Other tips for preparing safe smoothies are contained in this linked article.
Healthier Alternatives to Green Smoothies
The best course of action for health, then, is to opt out of the green smoothie diet fad. This is especially important if you have any sort of gut imbalance or candida issues.
If you enjoy green leafy vegetables, be smart about it. Don’t overdo like so many in the health community are doing with the best of intentions. Enjoy green drinks in moderation in salads. Or, cook them and carefully drain and discard leafy green cooking water. Never use it in soups and sauces!
Be sure to serve cooked leafy greens with a healthy fats like butter or coconut oil. Avoid margarine or any factory fats synthesized with rancid and/or GMO vegetable oils like Smart Balance. Using natural fats will facilitate maximum absorption of minerals.
Another option is to drink raw cultured vegetable juice or eat raw cultured vegetables. Not only will you get enhanced nutrition from the culturing process which adds enzymes and nutrients, but you will also get a beneficial and therapeutic dose of probiotics to help balance gut function and improve digestion. It also suppresses fungal overgrowth like candida.
Wheatgrass an Excellent Alternative!
Another option is to do shots of fresh, green wheatgrass juice.
Wheatgrass juice is very low in oxalic acid.
Here is a link to my favorite green juice recipe using wheatgrass and ginger. It is safe to drink regularly, daily if you like, instead of green smoothies. It is also an excellent drink for gently detoxing before pregnancy. The ginger assists with morning sickness issues too if you are already pregnant.
What to do if a Green Smoothie Diet Has Already Harmed Your Health
Are you already are suffering from some of the ailments described in this article? Do you suspect a high oxalate diet which includes green smoothies or a daily spinach salad may be the cause? If so, stop this practice immediately and consult with a holistic physician. You will likely need professional assistance to guide you on the road to recovery. Ridding your body of oxalate crystals that are potentially irritating one or more of your body tissues is no simple task! It is not advisable to attempt this protocol on your own.
Sarah, The Healthy Home Economist, author, Get Your FATS Straight
References and Additional Information
The Role of Oxalates in Autism and Chronic Disorders, William Shaw PhD
Top 4 Cleansing Myths to Watch Out For
Dear Sarah,
I make no pretense to be a medical doctor or scientist, just so we’re clear going in. Rather, as a Master Herbalist in private practice here in Vermont, I can report to you that green smoothies are a favored part of the natural healing programs that I have been putting people on for decades. Contrary to what you’ve said, everyone who has engaged this practice has seen benefits and no one has ever reported the slightest problem, quite the opposite. “Science” is infinitely confusing for most people and you’re only adding to the confusion. A suggestion–stick with direct personal experience and avoid scientific mumbo-jumbo. The proof is in the pudding. Green smoothies are awesome! Try to put aside the tendency we all have to validate the activities we engage in and find out for yourself whether something works or not. Experiment, explore, question. Some people I know have been doing green smoothies almost every day for 10 or even 20 years. They are among the healthiest people alive, vibrant, life-affirming, loving, energized and extremely active. Please take a second look before jumping to an unfounded conclusion.
Hi Jim, I’ve been having a terrible time trying to find more positive based scientific feedback around green smoothies. I’m new to green smoothies, only discovering them a few months ago. But as someone who does not like veggies raw or cooked, this was a perfect solution I thought as I’m happy to put it all in my vitamix and drink it down. I’ve been using a cup of various berries, a sweet fruit like banana or pineapple, and 1 to 2 cups of collard greens. Do you have any advise as someone who has been doing this for years as to what veggies to use for maximum benefit as well as the quantity per drink? I’m mid 30’s, in good shape, and suffer no known ailments, just want to be healthier. I’d like to have a formula that I can tweak to my own personal body. If I had a list of veggies I should use for maximum health and vary them every couple of weeks or months, that’d be great. I’ve just had a hard time finding good discussions around this, only the negative “if you eat or drink this too much you’ll harm yourself” which doesn’t help. Especially when “Too Much” means nothing to me, I need at least some quantifiable data. Thanks for any help!
I’m sorry but this article reeks of BS. I understand that for SOME people this could be an issue. But to further state that one should eat salads in moderation and not everyday is comical. The article then goes on to suggest we cook the greens in butter to “maximum absorption of minerals.” is down right irresponsible. The moment you cook a vegetable it begins to lose nutrients, and adding butter only adds cholesterol and saturated fat! Sure there is a little calcium in butter, but I’d rather eat an orange. Good grief, no wonder people are so confused about what they should be eating!
Where are the citings for the scientific evidence to validate this article? Do oxalates from dietary sources contribute to oxalic build-up in the body or does the Candida Albicans overgrowth create it? Why is the author so motivated to tell people to STOP drinking green smoothies instead of suggesting rotating types of greens used and drink in moderation? Chronic dehydration, high salt, low potassium diets, carbonated fountain drinks, sugar, and anti-acids all play roles in oxalate crystal formation. It is very irresponsible to discourage people from a high green diet with no evidence that it is harmful when the benefits are substantial.
How about we focus on soda & sugar instead of beating on people who have a way healthier route going on, even if it’s not perfect?
Soda is consumed by billions more people in far larger quantites than green smoothies and soda truly is devasating for our health in a myriad of ways. It literally is killing us. You will do far more good for mankind if you concentrate on getting people to stop drinking soda than putting the fear of god into people who are eating lots of vegetables. Let’s get some focus on the things that are really doing the damage instead of getting people on the right track all fired up and confused.
Carrie – most, if not all, who follow this blog do not consume sodas and are well aware of the damage they cause.
This article is a little out of balance. Yes, oxalates are a building block for certain types of kidney stones, bladder stones etc (I spent my PhD. studies on substances combatting this) but the underlying causes are a lot more complex. When we make green smoothies we use maybe 6 small Swiss chard leaves for the whole family (8 of us). That is much less than the average meal serving. The benefits far outway the “negatives”. One factor this article completely ignore is the amount of oxalates in black teas. Should all of the South stop drinking sweet/unsweetened tea? A reference for the oxalates in tea is http://www.ncbi.nlm.nih.gov/pubmed/12495262 BTW, the 6 cups of tea/day the article refers to are the small British style “cup and saucer” size, not the enormous glasses consumed here in the US!H
To compare relative oxalates content in foods the following link has done an adequate job …
Anyway, maybe the old saying “too much of a good thing …” holds true, so people with episodes of kidney stones should definitely take care. The rest of us would do well to do things in moderation. America has had too much of “super-size it”.
10 minutes ago · Like
I swear I can’t seem to get ahead when it comes to nutrition. I don’t like vegetables, never eat them, don’t want them. I finally thought I had a work around by creating my own smoothies with veggies and fruits, I can chug it, be done with it, and at least get some nutrition. Now it sounds like that is going to kill me. Except if I eat a salad in moderation it won’t? What if I take that moderate salad and make a smoothie out of it? Is there something about the blending process that is more dangerous than just eating it all raw? And what is moderate? I was eating a breakfast sausage biscuit at MacDonalds before work, now I switched to a smoothie. Both sound like they’re going to kill me. So I still haven’t heard what the healthy path is, but it sounds like there is no middle ground. Is it any wonder why Americans are so unhealthy, we can’t seem to come to a consensus on what will kill us and what is a good course of action.
Different greens have higher or lower amounts of oxalates. Spinach and chard are extremely high. Turnip greens, arugula, kale, lettuce and mustard greens are quite low and can be enjoyed in large quantities.
If you really want to be healthy though you need to eat more than just leafy greens.
I would like to continue to eat better, I’ve been feeling so much better than on my fastfood breakfast. But what is considered healthy and in what proportion. I have a vitamix so I make the drinks myself and have complete control over what goes in. Are high oxalate veggies right out, or are they still good in small infrequent batches. What would you or anyone reading this suggest for a monthly morning routine. For the past few months I’ve been mixing 1/2cup mixed dark berries (blue,black,rasp), 2 leaves of collard greens, with an optional banana or pineapple wedge, as well as a small spoon of coconut oil. Should I just vary the veggies I’m putting in on a weekly basis? Any particular veggies people recommend for health and more importantly that won’t cause more harm than good. And what proportions? I see too many terms like small, med, large, moderate, excessive, common sense…. Those don’t help. When someone comes to me and asks for advise on how to make their computer faster, I don’t tell them to get some RAM but use common sense on how much, or just get a moderate amount. Unhealthy folks like me have little to no understanding when it comes to nutrition, we just know we aren’t healthy. And thank you for that link, as someone who wants to live better I appreciate the help!
Joe, if you don’t have kidney stones or fibro, it isn’t a problem. Only 1.4% of people (20% of those who have calcium oxalate kidney stones) lack the intestinal bacteria to break down oxalates. Stay away from the antibiotics listed above, if you are worried take calcium citrate with your veggies, drink plenty of water and don’t live on unlimited spinach and rhubarb. Doesn’t sound like you are overdosing on the greens anyway.
It isn’t that green smoothies are a problem. In those people with an inability to break down oxalates, excessive high oxalate foods might -and the jury is still out with the research- do better with lower levels in their diet. (And with painful conditions may not want to chance eating high levels.) Oxalic acid in the correct amount helps with bowel movements and may even fight cancer, but too much can precipitate out and cause painful conditions.
Hey thanks for the help. I’m in the dark when it comes to nutrition, but am trying to turn that around, so it’s nice to know I’m not inadvertently causing more harm than good! I’ll start changing up the veggies I put in every month to give some variety too I suppose. I did notice one odd issue when I first started. I used only kale as my veggie, about 1.5 to 2 packed cups worth of it every day in my drink. After about a month of this, I started getting a tiny split in the tip of my tongue when I woke every morning. I stopped with kale and went to collard greens and no more split. Very odd, so I guess I’ll keep reading health forums and make sure I don’t supersize any one veggie!
There are a few gut bacteria that will degrade oxalates and the most promising is Oxalobacter formigenes which uses oxalates as its primary food. Other oxalate-degrading bacteria that have been isolated from human stool samples include Eubacterium lentum and Enterococcus faecalis. In contrast to O. formigenes, these species are able to use other foods than oxalate for growth, and whether they will degrade oxalate in the gut where alternatives are provided is not known. This research cited below does not mention Lactobacillis acidophilous which may also have a mild effect on oxalates.
20% of the population lacks Oxalobacter formigenes, the gut bacteria that degrades oxalates, possibly due to antibiotics listed below. It is being isolated to be sold as a prescription by Oxthera Products and also I understand by Ixion, but is currently not sold in the US. Unless it is available overseas (and I have no knowledge) the only way to get it now would be fecal implants from a healthy person without oxalate degrading problems, and that has a pretty substantial ick factor even if done with medical supervision.
The literature doesn’t specify whether O. formigenes is found in any probiotic foods. It is anerobic, so won’t grow readily in the presence of oxygen, Rice bran contains an enzyme that can break down oxalates though, so you might experiment with boiling food with rice bran (based on traditional Japanese bamboo shoot treatment.)
The article Oxalobacter formigenes and Its Potential Role in Human Health ( http://aem.asm.org/content/68/8/3841.full ) found that many of the antibiotics they studied can and do kill this microbe, with Doxycycline and clarithomycin being the worst:
doxycycline (the only nongeneric tetracycline studied)
clarithromycin (Biaxin)
chloramphenicol (Chloromycetin)
nalidixic acid (no longer used in US)
co-amoxiclav (Augmentin)
metronidazole (Flagyl)
polymyxin E (Colistin)
tetracycline
one strain of O. formigenes was sensitive to clindamycin (Cleocin)
Several of these are given for urinary or vaginal infections.
Avoiding these antibiotics may be more important than dietary changes while you build up a variety of gut flora.
Greens,in patricular leafy greens contain the highest levels of nitrate.Which protect the cardiovascular system from nitric oxide.Go look up The Hippocrates Health Institute,The Gerson Institute,The Budwig Diet.All of these alternative disease fighting diets contain veggies and juicing.Greens,especially chlorella,spirulina,wheatgrass,barley grass contain thousands of phytonutrients that help the body to detox and heal. Wheatgrass, for example ,is a blood bulider.It contains all of the vitamins and most of the minerals needed for human well being.Wheatgrass contains chlorophyll which is molecularly similar to hemoglobin. I believe that pastured meats,fish,broths,pastured chicken,pastured eggs,fermented cod liver oil,raw milk,raw cheese, are absolute staples to good health. But,I would be foolish not to include cancer fighting and health promoting greens.