How Badly Will Spinach Interfere with a Sluggish Thyroid? : The Renegade Health Show Episode #867

Monday Jul 18 | BY |
| Comments (53)

In this video, you’ll find out if spinach and it’s oxalic acid content is something to be concerned about if you have low or sluggish thyroid function.

I’m sure you’ve heard back and forth about this, but today I give you my understanding of the situation based on the information I’ve learned from others and the science behind it.

Take a look…

Your question of the day: Do you eat spinach regularly?

Click here, scroll down to the bottom of the page and leave your comments now!

Live Awesome!

Kevin Gianni

Kevin Gianni is a health author, activist and blogger. He started seriously researching personal and preventative natural health therapies in 2002 when he was struck with the reality that cancer ran deep in his family and if he didn’t change the way he was living — he might go down that same path. Since then, he’s written and edited 6 books on the subject of natural health, diet and fitness. During this time, he’s constantly been humbled by what experts claim they know and what actually is true. This has led him to experiment with many diets and protocols — including vegan, raw food, fasting, medical treatments and more — to find out what is myth and what really works in the real world.

Kevin has also traveled around the world searching for the best protocols, foods, medicines and clinics around and bringing them to the readers of his blog — which is one of the most widely read natural health blogs in the world with hundreds of thousands of visitors a month from over 150 countries around the world.


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  1. Lisa says:

    HI I heard also that in spinach the Oxalic acid leaches calcium from bones… to keep it at a minimum…it is in the nightshades I heard…MMMM

  2. Amanda says:

    Thanks for this interesting info. These animal studies that are usually referred to regarding diet, nutrition, etc are so misleading not to mention inhumane. Yet the popular press picks them up and translates them into yet another urban myth that the general population soaks up like a sponge. These myths then spread like a virus. Thank goodness we have the Renegade Health Show to counter balance.

    Re your questions of the day – I eat around 4 large bunches of homegrown spinach a week, mostly in smoothies. Lovely stuff!

  3. Velda says:

    Great information, Kevin. I have had a hypo active thyroid AND also a hyper activer thyroid. Neither one is fun. Either one can be very debilitating. Right now my thyroid is stable and I try not to do anything to upset it. I juice quite often, but not everyday. Also quite often when I juice I use spinach. I think spinach is good for you, but too much of a good thing might be harmful. All things in moderation. Thanks again, Kevin, for bringing such great information for us to think about.

  4. QC says:

    I eat spinach in my blended soup 3-4 times a week. I really like the taste of it. However, I was told to cut it down or eliminate it for a while for several reasons. Oxalic was one of them. The other one was that my iron level was too high and it was not from meat.

  5. Beth says:

    When I do eat spinach it is usually in a green smoothie. However, I do rotate the greens that I use in green smoothies: swiss chard, kale, spinach, arugula, field green mix, and cilantro are the ones I use the most.

  6. Moises Mehl says:

    It’s not the same eating cooked spinach than raw, the effect on cooked spinach with oxalic acid is different than raw. When is raw the effect is not detrimental. Look at the work of Norman Walker.

  7. Kim says:

    I have to say from personal experience that there is no “urban myth” regarding the oxalic acid in Spinach. I was hospitalized with extreme anemia and I was using spinach in smoothies and salads. Once I was released and educated about the dangers of too much raw spinach, I started using Kale and Romaine among other “safe” greens and my iron levels returned to normal. What is bad for some may not be bad for all, the same goes for what is good for some may not be good for all.

  8. Kristen says:

    I eat about 12oz per day (6 ounces in each smoothie)! Maybe too much? I will try to alternate with romaine and kale.

  9. Winter Fey says:

    I just started making green smoothies and I am getting just under a pound of spinach per week (hubby puts a little in his salads.) I’m starting to think that might be overdoing it! Unfortunately, my Whole Foods only carried 1 pound containers of spinach and I’m the only one eating it, so I’d hate for it to go to waste, but I don’t want to give it up either. Any suggestions, thanks!

  10. Ann says:

    Hi I used to eat spinach more often than I do now because of the build up of alkaloids that can happen if you stick to just one sort of green. So like Beth and Kristen I alternate my greens

  11. Oh my goodness, I eat more spinach than Popeye! As a bodybuilder competing in the Figure division, spinach is one of the ‘free’ foods that I can actually eat on my diet carte blanche. Everything else is very restricted & portion-controlled. Since I can eat as much spinach as I can stuff in my face, I seriously eat several cups of it per day, & have certainly never noticed any slowdown in metabolism–usually my metabolism increases the closer I get to contest.

    The one interesting thing though, is I have to cut out all spinach (along with many other foods) the week before a contest because it does contain a lot of natural sodium. Normally, this is good, but we sodium ‘deplete’ for a few days before contest to give us that really hard, dry, ‘ripped’ look on stage. The average person would NEVER notice this tiny bit of physique effect though, so it’s nothing to worry about at all!!! Just thought I would throw it in for an FYI. 🙂

  12. Kathleen says:

    Loved this very informative video. I didn’t know gluten interfered with iron absorption. Thank you for sharing this. At the end Kevin mentions something else that contains a lot of iron, but couldn’t understand what it was. Can anyone tell me what it is?

    I have spinach in my smoothie a few times a week. I alternate with chard, salad and bok choy, and if I can find it with kale (very rare here in Belgium). Good health to you all!

  13. Anna21 says:

    Those with sluggish thyroids should reduce the amounts of goitrogens in their diet (esp. raw goitrogens)- pine nuts, millet, strawberries, peaches, pears, green smoothies & cruciferous veggies/roots incl. spinach, maca, kale, broccoli, cauliflower, etc.

    Look at the overall % of goitrogens in the diet, not just spinach, & reduce consumption. Cooking goitrogenic foods eliminates most but not all) of the goitrogenic agents in these foods.

    I used to be on a typical SAD diet, then went on a raw food diet. To my surprise, my thyroid got worse. Now thyroid issues are usually caused by eating processed foods which are full of endocrine disrupters, & exposure to environmental toxins (pesticides, herbicides, plastics, cosmetics, etc.).

    However, thyroid issues may not necessarily be caused by goitrogenic foods, but they can be exacerbated by them. For those with sluggish thyroids, monitor your condition by getting blood tests every 6 months (TSH, free T3, vitamin & mineral levels, Iron, etc.) and tweak your diet as necessary, dogma be damned.

  14. Heather Her Oni says:

    Eat spinache most days, sometimes raw in salad greens, sometimes from frozen, which I lightly saute to taste. Yummy! This actually seems to be one of the foods I tolerate well on a almost daily basis.

  15. Leam says:

    Only eat spinach when we have it growing in the garden. Middle of summer not a great time to grow spinach in our area – wait for fall or spring, then it grows abundantly. For green food this time of year we have loads of purslane. Love it!

  16. Joanne says:

    Hi, thanks for the info……I watch Dr. Oz on chl 25 in the a.m. and in p.m., hes on 10am and 5pm…he has a lot of good info on his show…….your right on with the thyroid……Boston Fan-

  17. Sophia says:

    I have been using spinach in smoothies lately. It rocks because of the mild taste!

  18. Tyra McMahon says:

    If you have Gout watch out!

  19. Laura says:

    Kathleen, to answer your question, it sounds like he said “fennel is also a good source iron”.

  20. Laura says:

    Lisa said she heard spinach was a nightshade, so I looked it up on wikipedia.

    Spinach is not a nightshade. Spinach is in the Amaranth Family, Amaranthaceae, the same family as beets, chard and quinoa).

    The nightshade family is called Solanaceae and includes potatoes, tomatoes, eggplant, goji, cape gooseberries, chili, paprika, tobacco and datura.

  21. Susan Myers says:

    I don’t eat spinach everyday but I do eat it occasionally in salads and sauteed with tomatoes, olive oil and garlic.

  22. David says:

    I feel it is an individual based topic. For myself i have been eating spinach my whole life and it has not effected my health at all. I also feel that old studies can bring out skewed ideas about healthy food.

  23. Barb says:

    I love spinach, both raw and cooked. It is my go to veg when I don’t know what to pair with a meal. I eat it at least once or twice a week, more in the summer when it is fresh at farmer’s markets. I always have frozen spinach at home. As you can tell I’m not a “Raw” foodie. But I am trying to include more organic and raw foods in my diet. Since I have always enjoyed vegetables both raw and cooked, I am now in the process of figuring out what percentage of “Raw” foods I can live with. Slow process because I don’t want to move from one type of diet to another too quickly, I’ve done this in the past with very poor results, which usually ends up with me abandoning the diet because it caused too many problems.
    Kevin I enjoy your emails and videos, great information and good attitude towards food and lifestyles. Look forward to more in the future.

  24. Sando says:

    All I know is that when I owned iguanas – you were never suppose to overfeed w/spinach. One was an example of the oxalates causing metabolic bone disease, where the bones almost swell. This one was a spiney tailed iquana (meat eater) the green iguana (vegetarian) seemed to know not to over indulge and never had the problem. I often wondered it overindulgence of spinach would affect humans (other than Popeye)!

  25. hyesun says:

    i love spinach! don’t eat it everyday, just every once in a while. but i’d never heard that oxalic acid weakened the thyroid, like goitrogens do. i just thought it bound calcium. and i’m sure everyone knows this, but chard, beet greens, and purslane are also high in oxalic acid. oh, and did you know that iodine is contra-indicated in hashimoto’s and could even cause it. (according to author datis kharrazian) i’m hypothyroid and took iodine, because i’d heard “experts” say to take it if you’re hypothyroid. well, first of all, i didn’t feel any better. then my TSH kept going up. and then i tested slightly positive for antibodies, whereas before i hadn’t. i stopped taking it and my TSH went back down and no more high antibodies. i’m still learning to not blindly follow “experts” or gurus with anything, whether it be nutrition, diet, lifestyle, or whatever. i have a ways to go!

  26. Alice says:

    I just started to eat spinach, now there was a lost of thing about the spinach world that, I decided not to eat if. I have spinach 2 times for the month. I eat other veg to help with my thyroid.


    Alice Sutton

  27. Mary Vogas says:

    I have been eating cooked spinach every morning for about a month. After listening to you today, I think I will cut back a little.

    I read on the Whole Food website that the healthiest way to eat spinach is to cook it for one minute in an open pot, not steam. It states that “Cooking this way helps decrease the oxalic acid content by as much as 50%.: I cook mine for one minute.

  28. Linda says:

    I eat spinach about 4 times a week, either raw in a smoothie or lightly sauteed. Delicious – love the mild favor and the rich colour. My hemoglobin is excellent – perhaps the spinach has something to do with that.
    Keep on rockin’ with the info you and Annamarie share.

  29. Summer says:

    I eat kale or collards *almost* every day – rarely spinach (because it leaves a film on my teeth). Btw, do most people experience the film on the teeth and why does it do that? Of course, it doesn’t leave a film if I use it raw in a smoothie.

  30. n demuelemeester says:

    In Dr Ariel Policano’s article on Top 10 Foods for Thryoid:

    Maca root is a good choice for maintaining thyroid health for several reasons. Maca helps to balance the pituitary gland, which sends hormonal signals to the thyroid. It is a sort of top-down regulation.

    This traditional Peruvian root also contains nutrients that the thyroid needs. Maca root contains zinc, B-complex vitamins, iron and copper. All of these are likely to help improve thyroid functionality. One thing to note is that maca is not high in iodine. Sea vegetables are a much better source for this mineral.

    Try 1-3 teaspoons of maca powder in a smoothie each morning. I personally like to use maca in a salad dressing recipe because of its savory taste. I use the dressing on salads or as a sauce over kelp noodles.

    Main players: B-complex vitamins, iron and zinc

    For more info:

  31. Josephine says:

    Most vegans, those who I know, increase their iron blood levels with raisins. Not grapes, raisins.

    I avoid most of the nightshade plants for my joints’ sake. The blood type book confirms that this is a good move for me.

  32. Edith says:

    Why is there no mention of fluoride in this conversation, which is a huge factor in thyroid malfunction?

  33. Nikki says:

    I love spinach. I use it in my smoothies. I usually use about 2 cups greens per smoothie when using more mild greens like spinach and lettuces, or one cup for stronger ones like kale and bok choy. I have one to two each day. However, I do rotate my greens, so I usually only consume the same type of green for about 4-7 days before switching, so I think that gives my body enough chance to avoid any oxalate build up.

  34. Kyle Knapp says:

    Great info!!

    Enjoy Bend! My family and I are headed up there to Sunriver this weekend. Central Oregon is a great place!

  35. Anne says:

    I used to have a green smoothie with raw spinach every other day but after a while decided to cook the spinach for 1 minute in boiling water to reduce the oxalic acid. It’s easy to do and the smoothie is still wonderful.

    Initially I’d read about doing this on the World Healthiest Food Website see: which is full of useful information.

    Spinach is indeed a wonderful food.

  36. Yamina says:

    I don’t eat spinach. Quickly cooked, two or three minutes, it has a unappealing aspect ; raw, it has something bitter, rough that I dislike. I prefer lettuce, iceberg and romaine.

  37. rachel says:

    Iron is found in many foods including lentils,
    beans, and prunes and figs. I do consume spinach
    in my salads and smoothies, sometimes a 1lb. package every 2 weeks or so. Women have different iron needs than men do. I used to eat too much kale (2-3 bunches a week) and decided it was negative for my health so I cut down on the amount. Adjust according to your body’s needs. namaste’, rachel

  38. I make juice every day in our Blendtec, filling it with greens and pure water (1/2 carafe). Once blended, I strain and add a couple drops of spearmint oil to it. This is an amazing drink.

    I rotate the greens between spinach, kale, and spring mix. Whether this is the “perfect” thing to do or not, who knows? It just works for us because it’s something simple that we can do every day and it tastes amazing since it’s diluted as well.

  39. Dee says:

    Yes, in salads and smoothies. Good to know as I had only heard about the old warning.

  40. jamie says:

    not sure if you two are gonna make it to portland, beings that you are in oregon and all, but if you do, make sure to visit prasad. it’s the best vegan and raw cuisine portland has to offer. my friend is creator/co-owner and i’m sure she’d love to have you.

  41. Violet says:

    i used to just eat fruit for breakfast but recently switched to a spinach/fruit smoothie instead. my immune system improved so much, i no longer get every cold/flu my 5-year-old brings home from school. i need to eat greens every day, and while i do eat other greens and seaweed too, i go through almost a pound of raw spinach per week.

  42. Honey says:

    Hi, Kevin,
    In your clip on spinach I think that in passing you said that berries are high in oxalic acid.(???) I battle with hypothyroidism and have been careful to not consume too much oxalic acid BUT have been eating tons of berries lately (am about 80% raw foodist) and have been wondering if my thyroid has taken a dip again and was wondering why. Never thought of the berries being the culprit. Could you comment on this please?

  43. Luetta says:

    I love spinach!! I eat spinach at least four times a week in salads, juices, and stir frys. I hope it’s not bad for me?? 😀

  44. Patricia says:

    Great info thanks! I’ve been having raw spinach juice almost daily for years, and have had a lot of trouble losing weight over the last few years, so this might be why!

    I live in Ben – you might like to visit “Common Table” when in Bend – a very cool nonprofit restaurant that has healthy food and feeds anyone who comes in, regardless of whether they can pay.

    Thanks again!

  45. James Fischer says:

    I eat spinach every day in my salads without any problems. I have added Chia seeds in my salad seeds mix of raw pumpkin, sunflower and flax seeds. I was going to try some hemp seeds, but they looked clumped together and moist? is that common for hemp seeds?

  46. Michael Juneau says:

    Before I found out I had an allergy to wheat / gluten I was starved for iron and probably other vitamins / minerals. Spinach would give me a huge burst of energy probably due to its high iron content. I would even eat it from a can as a kid while watching popeye. I just loved the stuff. Now that I have eliminated gluten from my diet I am still having lots of spinach in my diet. I juice a pound of spinach with orange once or twice a day and its the best stuff on the planet. If I don’t get my green orange juice I get cravings for it. I highly recommend spinach in large quantities based on my experience.

  47. Dejana says:

    Hi Kevin, thanks for replying to my question and the great advice- test yourself before and after- so true. It really is the only way to know what works for my body!

  48. sheryl miller says:


    and @ Michael Juneau I too have the same spinach smoothie every morning and bananas are cheap we put one of those and it makes soooo creamy!

    Thanks for the info
    Currently assessing my thyroid!


  49. barbara says:

    interesting post and very important to me as I am hypothyroid I must keep raw cruciferous to a minimum as you noted. This info oxalic acid ifno with regards to tyroid is new to me.

    Therefore,spinach for all it’s goodness is my main green in smoothies along with romaine lettuce, and a few leaves of kale.

    The same holds true to my salads though spinach is not the main green, I use many in equal amounts – herbs, spinach, a bit of kale not much romaine, escarole, read leaf, butter lettuce, tatsoi etc.

    I also did not know that gluten inhibits iron absorption and low iron along with hypothyroid is an issue in my house hold where gluten, amongst other allergens was just found.

    Can you tell me if the interference of gluten and absorbing iron is regular iron issue or heme iron issue as the low heme iron is our issue. With the elimination of gluten and other allergens the iron should be looking better next set of blood labs in 3 weeks.

    Again, this was an beneficial video for our house!

    Can’t wait to start the RFC this coming Monday.

  50. Sanku Saikat says:

    can spinach be taken if i have thyroid??? please let me know asap

  51. I have been eating 4 cups raw spinach daily(for the iron) , mixed with strawberries and blueberres in a”Nutribullet” mixing blender(it actually pulverizes whatever is in it) for two months now. My TSH was 6.5 in October when I was also tested for vit D, and recently 10.1. I did not know until today about what spinach can do to the thyroid supplement. My primary did not discuss food that interferes with the supplement ever. I learned this from the Internet about the effects of spinach.

    I am positive that that the spinach is effecting my supplement. Even though I take the thyroid supplement, Levoxyl, 4 hours inbetween any food or other medication, such a raise in TSH is not normal. I am stopping the spinach immediately and will see how I feel in the next weeks. Maybe I can add it again but at reduced doses and not every day.

    It is too bad because since I added spinach to my daily diet my total chol went from 214 to 189. There was no change in LDL which has been a consistant 120.

    Do blueberries and strawberries have the same negative effect on thyroid meds?

    This has been a difficult past two months as my Vit D level was also low at 11.5 in Oct, my platelets were at 100,000, and then my thyroid med started not to work as well. Compound that with a molar that lost a filling and became infected along with the gum, I have not been feeling 100%. The dentist will not do the extraction(I don’t do root canal) until the D level comes up. I had another test last Friday and the D level was up to 15, platelets still low, and the TSH higher than in OCT. The connection HAS to be the spinach.

    Enjoy your Web Site.


  52. MMarg says:

    Wow! I had no idea spinach affected my thyroid. I have Hypothyroidism and have juiced spinach for over a month almost daily, sometimes 2 times a day. I put it in with bananas and strawberries along with protein powder. I also eat spinach in salads. Love the stuff makes me feel like million bucks. I’ll have to look into it a bit more and have my tyroid checked. I’m on a natural hormone. thanks for the info.

  53. Surf Dancer says:

    Oxalic acid is only an issue in cooked spinach, not raw. However, too much raw brassica can have a goitrogenic effect on the thyroid gland. Two different issues, Kevin.

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