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Conventional belief is that raw vegetables are always healthier than cooked, but this is not true depending on the plant foods eaten according to lab testing and anthropological evidence by experts in the field.
I stopped by one of my favorite healthfood stores today to pick up a large glass of fresh juice made from organic raw vegetables for an early lunch on the go. As usual, I asked for the a carrot, celery, beet, spinach and cucumber blend. But, hold the spinach. I definitely skipped the green smoothie too!
While this request is usually met with a simple nod by the juice bar attendant, this time the guy looks up and says, “Why no spinach? We have a lot of people that come in here and love the spinach in their juice.”
Ah! Great question!
The truth is that not everything should be eaten raw, especially vegetables!
Some raw vegetables must be cooked else you are actually harming yourself. Below is a rundown of what veggies should not be eaten raw either in whole or juiced form.
Cruciferous Raw Vegetables
Sorry to be the bearer of bad news, but cruciferous vegetables should be cooked before eating as they contain chemicals that BLOCK the production of thyroid hormone in your body! Considering that 2 out of every 3 Westerners are either overweight or obese and this is projected to jump to 75% by 2020, this is of particular importance as folks struggling with weight usually suffer from borderline to full-blown hypothyroidism.
Hypothyroidism is a condition where the thyroid gland does not make enough thyroid hormone, so someone suffering from this condition surely does not want to be eating foods that will block what little thyroid hormone is being produced in the first place!
Symptoms of hypothyroidism include cold hands and feet, thinning hair, fatigue, reduced or nonexistent libido, coarse dry hair, constipation, difficulty losing weight, and depression among many others.
Cooking crucifers reduces the goitrogenic substances by about 2/3. Fermentation does not reduce goitrogens in these veggies, but since fermented crucifers such as sauerkraut are typically eaten as a condiment and, hence, in small amounts, consumption is fine if the diet is rich in iodine.
Here is the list of common cruciferous vegetables that you do not want to be eating raw if you want to protect your thyroid gland!
Arugula, broccoli, kale, maca root, cauliflower, cabbage, turnip, collard greens, bok choy, brussels sprouts, radish, rutabaga, and watercress.
Notice that many of these vegetables are commonly included in fresh veggie juice blends or in salads. While an occasional arugula salad or cup of coleslaw is not going to do harm to most folks, it would be wise not to make a habit of eating/drinking any of these vegetables in raw form. Kale chips are a safe choice too.
Raw Vegetable Greens
Some veggie greens contain a chemical called oxalic acid. This substance is a very irritating to the mouth and intestinal tract. It also blocks iron and calcium absorption and may contribute to the formation of kidney stones.
The good news is that oxalic acid is reduced by a light steaming or cooking. Just be sure to discard the vegetable cooking water.
Veggies containing oxalic acid include spinach, chard, parsley, chives, purslane and beet greens.
Hmmmm. Spinach is known for being high in iron, yet eating it raw will not necessarily give you the iron you want because of the oxalic acid?
Yep, that’s right. Cook that spinach first if you are seeking an iron boost without the indigestion and don’t get hooked on the raw spinach salads!
Don’t stress about munching the parsley garnish on your next gourmet dinner, though. A little bit here and there is not going to cause a problem. Eat a big spinach salad everyday and it is virtually certain you will eventually succumb to kidney stones, according to Dr. William Shaw, Director of The Great Plains Laboratory for Health, Nutrition and Metabolism.
Other Raw Vegetable Cautions
Other vegetables that are best to avoid eating raw include:
- Raw potatoes contain hemagglutinins that disrupt red blood cell function.
- Raw sweet potatoes will give you gas.
- Raw, edible mushrooms such as the common white mushroom contain toxic substances such as agaritine, a suspected carcinogen. These substances are heat sensitive and are neutralized by cooking.
- Raw alfalfa sprouts are mildly toxic and inhibit the immune system. Eating large quantities regularly can make the skin overly sensitive to the sun or trigger autoimmune symptoms that mimic lupus.
Dr. Weston A. Price on Raw Vegetables
A good rule of thumb when considering the best way to consume your veggies is to remember the letter that Dr. Weston A. Price wrote to his nieces and nephews in 1934. In this letter, he strongly urged them to eat their vegetables cooked in butter. His research found that the bulkiness (fiber) of raw vegetables interfered with the human body’s ability to extract minerals from them via the digestive process.
So, should you drink your veggies raw? Of course. Raw vegetable juice made from veggies that are safe to consume uncooked is a wonderful way to get a fast infusion of easy to digest, colloidal minerals. It is also highly alkalizing to the body and a proven way to gently detox the gut.
The great thing about veggie juice is that the fiber is removed, which is the “bulkiness” that Dr. Price found interfered with the mineral absorption.
However, if you are going to eat the fibrous portion of the vegetable, it is best to cook them in butter as advised by Dr. Price to enhance the availability of the minerals. The fat in the butter permits greater absorption of the minerals, and besides, buttered veggies taste fantastic!
References
Nourishing Traditions
The Role of Oxalates in Chronic Disease, William Shaw PhD (Director of The Great Plains Laboratory for Health, Nutrition and Metabolism)
More Information
Best Green Juice for Congestion
Nightshade Vegetable Contraindications
Cleansing Myths
Moderation certainly is the key. Overconsumption of any food can certainly lead to problems.
Sara,
Even people who do not seem sensitive to oxalates can be asking for trouble down the road by consuming too many of them. The body sequesters them. They can build up unnoticed over time and can cause damage in all parts of the body, depending on the individual. I also suspect, based on my own experience, that this kind of gradual oxalate damage may be at the root of numerous problems attributed to “aging” such as poor sleep and irregularity.
I am not saying that everybody should avoid all oxalates. That is almost impossible anyway. But I am saying that it is helpful to have accurate information on how much oxalate is being consumed. For example, going by the list accompanying William Shaw’s article, one would think that pecans and peanut are the only high oxalate nuts to watch out for. Per 100g of nuts, raw pecans contain 46.5 mg., raw spanish peanuts contain 142 . But almonds contain a whopping 465! Without this kind of accurate information people may be eating a much higher oxalate diet than they realize.
Notice the influx of low oxalate diet people? 🙂
Although one may think they are not sensitive to oxalate, at the very least oxalate is absorbed at 22%. That’s for the “non-sensitive,” normal people, without leaky gut syndrome. If you have any chronic condition or auto-immune disease, the amount you are absorbing is likely more.
Oxalate cripples mitochondrial action by botching up enzymes and transporters, that your body needs for detoxification.
You can learn more that the website I included http://lowoxalate.info
or access the latest spreadsheets on oxalate content by joining a great group of people from all walks of life who are on the yahoo group trying_low_oxalates.
I did not know I had an oxalate problem, and had no kidney stones or any symptoms which I would have related to oxalate. I probably consumed thousands of milligrams of oxalate a day. I thought the condition of my health was typical of a 40 year old mom. That is stressed, anxious, harried, “losing it,” tired, etc.
Going low oxalate, for my children, who are “not quite neuro-typical,” has allowed me to get off Wellbutrin, has allowed a chronic skin condition to heal, has allowed me to get off allergy medication, has gotten rid of my brain fog for the most part. My carpal tunnel is GONE!!! I feel at least ten years younger.
I know there will be people who cannot believe they could be healthier and they continue to have a salad of spinach leaves, beets and almonds (Oh my!) Which by the way would have been something I would love, back in the day.
If you refuse to give up your oxalates, that is your choice of course 🙂 Please consider taking a calcium citrate supplement about 15 mins prior to eating. This increases circulating calcium and will allow the oxalate to bond up to it and be excreted, and reduce the amount of oxalate absorbed. This calcium should not be included in your daily requirement for bones (which should be taken on an empty stomach.)
I juice veggies daily, usually 1-2 heads romaine, 4 carrots, half cucumber, and half pound spinach. Is this ok? I Loethe taste aand thickness of spinach juic. I notice no kidney issues, but i have been struggling with ssome health issues for several years and hence why I started juicing(uulcerative colitis, autoimmune disorders, chronic constipation, cfs, fms, nerve damage, etc)
Thanks
Bee,
I am a “functional” nutritionist, and may be able to assist you in your journey back to health.
Arnold
http://www.misterpaleo.blogspot.com
Oh how I wish cooking eliminated oxalates. I got my first kidney stone while eating cooked spinach in my omelet most mornings. Now I know that while some of the oxalate leaches into the cooking water most remains in the food. Steaming or sauteing won’t eliminate any of it.
My younger daughter is very sensitive to oxalates and cooking high oxalate foods doesn’t make a difference for her. While many people are just fine with oxalates, many others have serious health consequences from consuming them and I would hate for someone to cross oxalates off their list as a possible source of the problem just because they eat high oxalate foods cooked.
If folks are sensitive to oxalates, then completely avoiding veggies that contain them such as spinach seems to be the best route to go. For those of us not sensitive to oxalates or who do not consume a high-oxalate diet, wilting the spinach before consuming (and discarding the cooking water) seems wise as this is the traditional preparation method – traditional cooking methods have their roots in maximization of nutrition and minimization of anti-nutrients.
I like your original article in many ways, but you’re really side-stepping this issue.
The point is that cooking or wilting does NOT significantly reduce oxalates. Yes, that may not be much of an issue for many people, but for those that it is an issue your article contains inaccurate information that could be harmful. How about an edit?
If wilting spinach did not improve nutrition and reduce antinutrients, traditional peoples would not have prepared it this way – they would have avoided eating it entirely or would have eaten it raw as cooking it wouldn’t have made any difference.
Sarah – with all do respect, sometimes you need to back away from that “traditional” stuff. You must realizes that these traditional families with their traditional meals all had traditional diseases – heart disease (butter will do that), diabetes, cancer, auto immune issues, high blood pressure, dental issues, gastro intestinal issues.
You make it seem as if this diet because it was traditional that it was good, wholesome and healthy. You have to learn to break with some traditions or at least modify them as we move into this next century, with all of the new information that we have – based on new technologies that we have which didn’t remotely exist in Dr prices time.
I am not saying we have to negate and dispense with Prices findings – but every great scientist from copernicus to newton to darwin to einstein, (even Sigmund Freud), to the current stephen Hawkings has had their work questioned, modified, rejected, advanced, tweaked etc etc .
To cliing to Dr price’s every word as well as the person who wrote the Traditional book, like it’s the bible and “so it is written so it must be so” type of thinking, is handicapping your own personal growth and somewhat debilitating to what we can learn from this blog – Heck, even the bible gets re written over the years
Oxalate always interacts with the biochemistry of the body- people who are sensitive are people who know that some of their symptoms are caused by this interaction, but they are not the only ones affected by eating oxalate. Traditional peoples who ate traditional diets had a different physiology then we do today because of the constant assault on our gut flora that modern life is. A thriving and robust got flora is essential to safely eat relatively high levels of oxalate. Anyone who has ever taken antibiotics, or whose mother or grandmother ever did, has been set up to poorly tolerate oxalate as the bacteria that helps us degrade it is very sensitive to antibiotics. Wilting spinach may reduce other anti-nutrients but it does not reduce oxalate for anyone. Including spinach in a diet has been shown to reduce calcium levels in the body. The information that you have posted here affects everyone, not just those of us who are aware that we are sensitive.
Sara,
As far as I know the *only* up to date and accurate source of information regarding oxalate levels can be found in the files of the yahoo group Trying Low Oxalates and listed as the spreadsheets. They report on recent testing from the only two organizations that are doing these tests on an ongoing basis. They have tested some foods under various preparation methods and clearly show that with extremely high oxalates such as spinach even boiling and discarding the water make very little difference.
Having lowered my oxalate intake several months ago I am learning that oxalate damage can be cumulative and very wide ranging.. Much more so than is commonly reported, even in the two articles on the subject that appeared in the Wise Traditions Journal recently. It is a topic deserving of much more research.
Your information regarding oxalates is wrong and can easily be found contradicted within the information of the link you provided by William Shaw. Oxalates do not disappear when cooked And it is more than just greens containing high and unhealthy amounts.
As suggested above, you really should research further and redo your post, the harm you can do by leaving it as is, is unjustifiable.
Hi Sarah, I’m a big fan of your blog and while I generally agree your premise here about not eating veggies raw as much, I did want to point out that it is NOT true that heating oxalic acid destroys it or lessens it. I am very oxalate sensitive and have researched this thoroughly as it is extremely important to me and my son (who is mostly recovered from autism). I am also normally a big fan of NT but this is one thing that they got wrong.
The only way to lower the oxalic acid content of food is to boil it as some oxalate is water soluble. The boiling liquid must then be discarded. This only removes a small amount, and so only helps with foods that are already borderline low enough to eat. Steaming and sauteeing does not reduce the oxalate content at all. All of the veggies that you list as high oxalate are still extremely high in oxalic acid after cooking- in fact, sometimes cooking INCREASES the availability of oxalate, for example in spinach and swiss chard (for reference, a low oxalate diet is normally between 40-60 mg per day):
Raw baby spinach has 160 mg oxalate per 1/2 cup
Raw spinach has 114 mg per 1/2 cup
Spinach steamed 15 minutes has 697 mg per 1/2 cup !!!!
Spinach, boiled has 334 per 1/2 cup
Raw swiss chard has between 174-210 mgs per 1/2 cup (depending on color)
Steamed chard has between 487 and 921 mg per 1/2 cup (depending on color)
Boiled chard ranges from 293 to 375 mg per 1/2 cup
These are the most recent testing values available. There are many old values available online that were done using less accurate testing methods. People with Fibromyalgia, Chronic Fatigue Syndrome, migraines, urinary or genital pain and problems including Vulvadynia, sensory processing issues, autism (according to the Great Plains lab, 84% of people with autism test as having an oxalate problem), visual disturbances or eye pain, or various skin problems are all likely to be sensitive to oxalates. Additionally, since oxalate binds to minerals and metals, having high oxalate levels in the body makes a person more likely to be injured when exposed to toxic metals such as mercury or lead.
This is such an importnat issue, please do more research about it and re-do your post. Many people look to you for advice and while you usually are right on in this case this information is wrong and will actually hurt people.
Wow, great info Sierra. I hope Sarah reads this and responds or reposts. It’s dangerous to have this misinformation out there.
Sierra, I can’t help wondering about how much sense it makes to compare, for example, 1/2 cup of raw spinach to 1/2 cup of steamed or boiled spinach. I know whenever I cook spinach the physical volume decreases enormously. It would make much more sense to me to compare the contents of 1/2 cup of raw spinach leaves to what started out as 1/2 cup of raw spinach leaves and ended up as perhaps 1/8 cup of cooked spinach.
So, just noodling this through… would dried parsley/ chives contain oxalic acid? I guess they are not cooked but just dehydrated at low temp… Your thoughts? Thanks!
Hi Jenn, yes they would but if you are using them in small amounts as a garnish or whatnot, it should be fine. The idea is not to consume these veggies in raw green smoothies or to eat them frequently as in a daily spinach salad.
Thanks for this information. Since I usually have more raw spinach and other greens than I can eat, I cut them in small pieces and add them to my taco meat, along with onion and garlic. They practically “dissolve” in the frying pan, and I enjoy knowing that I am getting the “green” nutrition that is needed.
What a creative way to eat your greens! Thanks for sharing! 🙂