Health Dangers of Cruciferous Vegetables

Health Dangers of Cruciferous Vegetables

Health Dangers of Cruciferous Vegetables

Health Dangers of Cruciferous VegetablesIn our look at the Health Dangers of a Plant-based Diet we turn to the cruciferous vegetables. You might be surprised to learn that broccoli and brussel sprouts have a dark side. I mean these are the vegetables that kill cancer, right? How can there possibly be health dangers of cruciferous vegetables?

Well just like other plants, these vegetables place a high priority on survival. And this means protecting themselves with phytochemicals. The cruciferous vegetables use a special chemical called glucosinolate to deter pests. [r, r] Here we’ll look at glucosinolates and their role in the health dangers of cruciferous vegetables.

Health Dangers of Cruciferous Vegetables – What are they?

Last week as I was walking to perimeter of the grocery store (headed to the butcher) I realized how many vegetables are from the cruciferous family. It’s not just broccoli and brussel sprouts. But it also includes cabbage and cauliflower, kale and collards, radishes and arugula, mustard greens and mustard seeds, and the list goes on.

The crucifers are just like every single plant specie commonly eaten today; it’s vastly different from its pre-agriculture predecessor. We transformed these plants through artificial selection to get the biggest, most pest-resistant breeds possible.

Cabbage, broccoli, cauliflower, brussels sprouts and kale are all different cultivars of a single species, Brassica oleracea. But generation by generation, we engineered this one plant’s leaves, stems and flowers into new “foods.”

You may be familiar with these crucifers because of their pungent smell. It’s the sulfur. And it’s a part of their defense.

Health Dangers of Cruciferous Vegetables – “Broccoli Bomb”

sulforaphaneThe crucifers like broccoli have this chemical called glucosinolate. I like to think of this chemical as the main ingredient of the “bomb.” They also have another chemical called myrosinase. I think of this as the “matchstick” that lights the bomb.

While growing out in a field the bomb and the matchstick sit in separate compartments so that the broccoli doesn’t blow itself up.

But when a little hungry animal comes looking for a snack and bites into the broccoli the bomb gets lit by the match. The explosion that results are bioactive chemicals call isothiocyanates. [r, r] One of the most well-studied isothiocyanate is call sulforaphane.

Sulforaphane

Sulforaphane is a pungent molecule (perhaps you’ve cooked broccoli and smelled it…) that can deter and kill insects, bacteria, and fungi. It causes cellular apoptosis (cell death). This happens in the cells of these small predators as well as human cells.

If you eat broccoli about 75% of the sulforaphane will be absorbed into the bloodstream and taken up by cells.

Once inside sulforaphane can damage important intracellular structures like mitochondria and enzymes.

The damage increases reactive oxygen species (ROS). And in an attempt to limit the damage, glutathione, our powerful endogenous antioxidant, binds with sulforaphane to get rid of it as quickly as possible (~2-3 hours after eating it). [r] This depletes our glutathione (our most potent human antioxidant) leaving cells vulnerable to further oxidative damage.

Sulforaphane can even disrupt epithelial barriers providing yet another plant chemical that can contribute to “leaky gut.” [rr]

Sulforaphane and Cancer

It’s not surprising that this cell killer has been recognized as an anticancer chemical. It kills cells. Cancer cells and healthy cells. [r, r, r]

Isothiocyanates like sulforaphane trigger the activation of Phase II enzymes. [r] This is like turning up the dial on the human immune system.

For some reason, research paints this in a positive light. Sulforaphane is a hero. Isothiocyanates increase our natural antioxidants. They say it’s a hormetic response. [r] If it doesn’t kill you, it makes you stronger.

I see it through another lense though.

When the body encounters something that is damaging, it wants to get rid of it. To do this it will upregulate an army to fight it. Some of these troops are antioxidants like our friend glutathione. While this is good in the context of fighting a cancerous cell or ridding the body of sulforaphane, I don’t think sending the troops to battle on a constant basis should be seen as a good thing.

The fact that the body puts such a vast importance on getting rid of sulforaphane as quickly as possible suggest to me that it’s more of a danger than a cancer-killing sidekick.

For me, a helpful analogy is to relate to chemotherapy treatment. It is very effective at killing cells. And while the intent is to kill cancerous cells, there is often a significant amount of “friendly fire” and the death of healthy cells as well.

Most people don’t take low dose chemotherapy as a cancer prevention strategy. There’s a reason for this.

Health Dangers of Cruciferous Vegetables – Thyroid Health

goiterThe isothiocyanates created by chewing up broccoli can have potent antithyroid effects and interfere with thyroid hormone production. They compete with iodine and thereby block its uptake by the thyroid. With inadequate iodine there is decreased production of thyroxine and potential for hypothyroidism. [r]

The abnormal absorption of iodine also provokes hypertrophy of the thyroid and goiter. [r]

And it’s not just humans, but animals too.

Oil meals, like rapeseed meal for example, are important protein supplements for livestock. And they are high in glucosinolates. Animals can tolerate up to 5-10% rapeseed meal in their diets before suffering from goiters, depressed growth, gastrointestinal irritation, anemia, perosis, poor egg production, and liver and kidney lesions. [rr]

The high sulfur diet can result in trace mineral deficiencies and polioencephalomalacia, a neurologic disease in ruminants.

Health Dangers of Cruciferous Vegetables – What to do

If you decide to eat cruciferous vegetables, it’s a good idea to take some protective measures.

  • Adding extra iodine to counteract the thiocyanates is helpful. However, additional iodine consumption cannot counteract other glucosinolate byproducts like oxazolidine-2-thiones which also blocks iodine preventing thyroxine production. [r]
  • Avoid sprouts and seeds as they can have orders of magnitude more glucosinolate than matured plants. Plants protect their babies. Eat them with caution.
  • Freezing as well as boiling them can help reduce the glucosinolate concentration (~50%).

Heat actually destroys the myrosinase (the matchstick that lights the bomb); however, the bacteria in our gut can act as the lighter, so sulforaphane will still be produced. [r]

As with other plant chemicals, the poison is in the dose, and an individual’s ability (or lack thereof) to disarm the plant poisons.

An elimination diet (like “Level 3” in the 30 Day Guide to Going Full Carnivore) is a very effective way to determine your ability to handle certain plant foods, which (if any…) are ok, and in what quantity.

[NOTE: You can now access the complete “Health Dangers of a Plant-Based Diet” series here]:

21 Replies to “Health Dangers of Cruciferous Vegetables”

  1. Very interesting. I’ve been religiously eating cruciferous vegetables for decades, but I have some autoimmune issues. Perhaps this has been part of the cause.

  2. I have a question, I understand that plants have toxins and see where you are coming from, but how come animals don’t have similar toxins? Obviously they don’t want to die either. Arguably even more so than plants. My hypothesis is that our body has adapted to eating meat for so long that we can tolerate whatever toxins are in meat. However, it is just a guess. Is there any evidence to either support or counter my claim?

    1. That’s exactly right. We’ve become ill-equipped to handle these toxins over millions of years of human evolution (https://www.kevinstock.io/health/what-did-humans-evolve-to-eat/)

      That said, a natural diet for a cow is grass. Though many are grain-finished today – and we do see an impact from this. Grain-finished meat, for example, has a higher ratio of omega 6:3 fatty acids, it’s lower in CLA, and the fat is more likely to store plant-based toxins (which cows are far better equipped to deal with than humans).

  3. Where is the research to back what you are stating about the dangers of eating plants? This is hard to believe and I do not see anything sited here. Man was created by God and all the fruits and vegetables were food for man. Until the fall of man, meats were not eaten. If I talk with a nutritionist, would they be in agreement with you deterring eating vegetables? Seems odd they would be in the dark if this research is legitiment.

    1. Hi Marsha please see the (R) references throughout the posts.

      And no I’m not in agreement with most nutritionists as their recommendations have resulted in unprecedented chronic disease.

      But of course, and by all means, you can believe and eat exactly as you wish 🙂 I’m just offering another perspective.

    2. You discredit your (valid) argument by bringing religion into a conversation about science. Also, lets leave it to the PHDs and qualified scientists to present reseach .

      1. Well, since you can’t do science without the one true and living God that created it; it’s right to bring His word into every discussion on science.

    3. I am getting tired of people using the “Where is the research” line to avoid obvious truths. Practically all of the “research” is funded by the same companies that provide the product being researched. So of course it is biased and has been for over a hundred years. You can talk about the complex science all day.(it is rather fascinating) However, all you need to know is this. Almost everything we eat today in modern society we could not have eaten, would not have eaten, and simply didn’t exist. In regard to fruits and vegetables, of course they can be used as food. The truth is, the fruits and veggies of today are not even close to the same quality or even species. Perhaps you could source high quality fruits or even grow your own, but the energy required to do so would exceed the caloric and nutritional gain in my opinion. Now when it comes to the “fall of man” causing the consumption of meat I am unsure what that proves. I’m not sure if you have read the Bible but milk, meat and other animal products are mentioned far more often than vegetables and in a more positive view. I recommend “Nutrition and Physical Degeneration” as well as “The untold story of Milk”. The former will help you understand what we have always eaten and the effects of modern diet and the latter sheds light on the corruption of medical institutions following the early 1900’s.

      1. Brendon, that was a very thorough and throughtful reply. Thank you! I have been a Carnivore for 2 months, and acting as my own free will Guinea Pig, the results so far have been amazing…how is it even possible to gain muscle size and strength while losing fat at the same time?? How by eating these huge quantities of protein cause such mental clarity? How is it possible to reduce high blood pressure, have an excellent blood profile and beat every PR in the gym I had when I was 30, at the age of 59? It’s a simple equation…I’m made of meat and that’s what I will feed it.

  4. I just made a recipe that had broccoli cauliflower kale and brussels sprouts. They were sautéed. As soon as I ate them I felt like I had been poisoned. So I googled toxicity in those foods. And came across your article. I am never eating that stuff again. It is poison to me.

  5. Thanks Kevin for eye opening info that will receive scrutiny from a society that’s been lied to for so long, it somehow becomes the (Ugly) truth. Coming from Keto to Carnivore, my digestive system has never felt better in all of my 59 years. My clarity of mind, especially getting up in the morning (it’s like instantanious!) instead of feeling like I’m trying to crawl out of a 12′ hole. Adios veggies, grains and nuts, I’ve got a Tomahawk steak to cook!

  6. We have to consume everything in moderation. Every substance is toxic it is just the matter of amount. Plus everybody is different one may have allergy or intolerance to the ingredients of broccoli or any plant and animal product. Nothing is 100% true or wrong. Therefore test everything before drown yourself in smoothies or totally giving up on them.

    My kids loved the idea of dangerous broccoli.

  7. Hi Kevin, I’d also look into mercury poisoning if you’re doing better by staying away from cruciferous veggies. They are full of sulfur and this is one of the pathways that gets damaged by mercury, IT’s the reason for the many food intolerances and allergies of our time, mainly gluten, casein, salicylates and sulfur. Mercury damages methylation which is responsible for DNA formation, and thousands of enzyme processes are at risk. It’s most insidious action is DNA formation of T cells get damaged, this is when B cells are left unregulated and auto immunity begins. People are healing all types of neurological and autoimmune disorders using ACC frequent low dose chelation, the only safe way to move mercury out of the body. Amalgams, vaccines and CFL bulbs are the biggest culprits, many people have no idea how they were exposed.

  8. I’ve been “allergic” to cruciferous vegetables. I will develop “explosive” cramps and diarrhea WHILE I AM SITTING THERE EATING. Half way through my meal, I will jump up and run to be sick. I also have an allergy to sulfa drugs. Related? Are there other foods that contain these chemicals in smaller amounts, or are cruciferous veggies totally unique?

    1. Very interesting – thanks for sharing your experience!

      I’d recommend checking out the full pdf download of “Health Dangers of a Plant-based Diet” for a deeper dive into your question.

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