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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
If your also saying cooking vegetables and throwing out the water, what about when I make a vegetable soup? Is that not healthy anymore?
If you make soups with vegetables that contain anti-nutrients, the answer is yes… that would an unhealthy (and nontraditional) way to make soup. Best to cook anti-nutrient high veggies separately, toss the water, and then blend into the soup broth. For veggies that are safe like carrots, etc, you can cook them right in the soup broth.
Would the vitamin c supplements you suggested in another article be low oxalate? I wasn’t sure to post this question here on the oxalate article or over on the C article. I know vitamin c (even natural forms) can somehow be problematic for those who are oxalate sensitive.
HI there, Great article but you might want to clarify your generalization of “raw, leafy greens” and list specific greens associated with high oxalates (spinach and a few others). Not all raw leafy greens are high risk for oxalates, lettuces are fine for example (very very low oxalates). I make lettuce smoothies every day, avoiding spinach and select other greens due to oxalates. Just a thought that might clarify things for the reader. This is definitely a topic that more people (and physicians) should be aware of – thanks for spreading the news further!
I agree. Our ancestors never ate green smoothies. They’re a fad.
Kale and other Brassica oleracea species of vegetables, cabbage, broccoli etc are all low oxalate.
Here’s more with a detailed list on oxalate levels. You may wish to recheck your sources. This info from the Univ of Chicago. https://www.thehealthyhomeeconomist.com/low-oxalate-diet/
You write extensively about the negative consequences and scary symptoms of high levels of oxalate in the body, and that kale does indeed contain oxalates. However, the article contains no evidence of a link between people who regularly consume green smoothies and the emergence of these heath complications as a direct result. Would you be able to point me towards any such evidence? Thank you.
Yes, see the reference of the PhD in the post who has witnessed these problems per his work with Great Plains Laboratory.
I’m totally pro-vegan, but green smoothies really can cause high oxalate levels. The article has a wealth of information on decreasing absorption of oxalate from foods and decreasing calcium-oxalate in the kidney for stone prevention.
From the article:
Here are some other tips for minimizing problems from oxalate:
Boil high-oxalate leafy greens and discard the water.
Meet the RDA for calcium. Eat high-calcium foods or take calcium with meals; calcium citrate if you have a history of calcium-oxalate stones.
Drink plenty of fluid.
Do not include large amounts of high-oxalate vegetables in your green smoothies.
Do not take large amounts of vitamin C.
So i mixed lemon with cucumber plus honey and iced water after drinking it i felt dizzy and nauseated and it is my 1st day of drinking green smoothie .. so is it safe to drink it every day or not (p.s also im just trying to maintain weight)
For about 3-4 years now I’ve been drinking a green drink mainly containing salery, carrots, Kale, apples, cucumbers, cabbage, sometimes asparagus and or spinach and or broccoli and or cilantro . we blended it up in a vita-mix with water and kefir. we make about 3 gallons of green drink at a time and last us 2-3 weeks before we have to make more. The kefir is made from our farm fresh goat milk. From what I read this is the only real way to drink smoothies daily and have the oxalates removed from the smoothy. I drink 2 cups morning for breakfast and keeps me going quite a while, and sometimes add another cup or 2 of carrot, apple and salery keifer smoothy for dinner. before I started doing this I was about 20 lbs under weight no matter how much I would eat I’ve improved my health greatly
I found that green smoothies make my stomach turn and also cause dizziness, the one I had today is the last one I will ever consume. What irritates me more than anything is that I bought into this fad and spent a lot of money and probably damaged my health. What about fruit smoothies though, would this be a healthy alternative? I’ve read that too much fruit is also bad for you 🙁
fruit smoothies are fine if you mix in some healthy fat and protein to mitigate the blood sugar spike from all the fructose in the fruit. I have some good recipes on this blog for this type of smoothie. Here are a few:
So glad I came by your article. So just want to confirm what is safe for juicing regularly: cucumber,celery , romaine, carrot, beet, onion, garlic, ginger. What I am not sure about and have been juicing daily is: cilantro, parsley, fennegreek, dandelion, herbs from my garden (oregano, rosemary, tarragon, chives etc). I really would appreciate any clarification you can give me. What is o.k. daily, what could be o.k. weekly. I haven’t been putting any cruciferous such as brocolli, collards etc.
Not sure what you mean by regularly. Beet and celery are rather high in oxalates too. Not as much as spinach but if you are juicing every day, you might want to vary that more. https://docs.google.com/spreadsheets/d/1nbDZPxhAW4It-m2-c460w6eGr4dMSIeDiQdqg3MaRgQ/edit#gid=1354389148