For National Kale Day I thought I'd explain why I personally cook all my kale quite thoroughly in olive oil or BACON.

Mind blown.

Raw Foodies, I love you, I REALLY REALLY DO (but, PLEASE eat some meat!  You’re looking a wee bit pale).

Not everything should be eaten raw, especially vegetables!

Some 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.

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, cauliflower, cabbage, turnip, collard greens, bok choy, brussels sprouts, radish, rutabaga, and watercress.

These foods are better for you if you cook them in bacon.

Mind blown.

So lettuce or spinach is okay for a salad but cabbage, arrugula, and kale are not.

Never will I eat a raw cruciferous vegetable again.

These are good vegetables to steam:

Some veggie greens contain a chemical called oxalic acid.  Oxalic acid is a very irritating substance 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 cooking water.

Veggies containing oxalic acid include spinach, chard, parsley, chives, purslane and beet greens.

I want to get a fancy steamer someday.

The vegans fight back:

Cruciferous vegetables such as kale, bok choy, collards, turnip and broccoli do contain goitrogenic glucosinolates which produce thiocyanates that compete with iodine for absorption by the thyroid gland. Sounds alarming, right?

However, the research also shows that consuming foods that contain glucosinolates does not increase the risk of hypothyroidism unless accompanied by iodine deficiency.

I have consumed three to four cups of raw kale, bok choy or other cruciferous vegetable in my green smoothies since 2008. I recently had routine blood work done, and I checked my thyroid just to see. The lab results indicated that my thyroid function is 100% normal and the numbers are right in the middle of the healthy range.

More about cruciferous vegetables, iodine and thyroid health:

http://whfoods.org/genpage.php?tname=george&dbid=250

http://lpi.oregonstate.edu/infocenter/foods/cruciferous/

http://www.japi.org/thyroid_special_jan_issue_2011/article_02.html

I'm still looking for more SCIENCE about this.

Here's another site that says not to eat large quantities of raw cruciferous vegetables:

A question that has come up often on our community page Ask the Nutritionist is ‘what fruits and vegetables should I avoid if I have a thyroid condition?’ It has been shown that some vegetables can interfere with the way thyroid hormones are manufactured by the thyroid gland.

Your thyroid is a butterfly-shaped gland that sits near your vocal cords and produces thyroid hormones that control your metabolism. Symptoms of an under active thyroid gland can be low body temperature, constipation, weight gain, hair loss, dry flaky skin and nails, fluid retention, slow reflexes, fatigue and slow thoughts and cognition. Thyroid problems can develop for a number of reasons, but the most common causes of thyroid problems are nutrient deficiencies such as iodine and selenium deficiency, autoimmune disease, genetics, stress and environmental factors. The most common type of thyroid problem is hypothyroidism (under active gland).

Goitrogens are substances that suppress the function of the thyroid gland by interfering and blocking the enzyme that allows your thyroid to use iodine, this can cause an enlargement of the thyroid (goitre). Iodine is important in the formation of thyroid hormone. So by inhibiting iodine, there will be a decrease in thyroid hormone.** Iodine deficiency has re-emerged in Australia in recent years.

If your diet is deficient in iodine and/or selenium, or you have an underactive thyroid, known as hypothyroidism, eating raw cruciferous vegetables can further suppress your thyroid hormone function. So it is suggested to avoid consuming LARGE amounts of RAW cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, bok choy, broccolini, chinese cabbage, kale, kohlrabi, radish, mustard greens, collard greens, choy sum, horseradish and turnips.

Most of the Internet seems to agree: Cook your cruciferous vegetables.

Well yes and no.  

Sarah at the Healthy Home Economist raises superficial complaints about raw foods that are not much help in guiding the average diets of raw omnivores--omnivores rarely fixate on one type of food, nor do they need to make up for dietary deficiencies due to eating disorders or eating consistently for other than daily nourishment reasons (moral, ethical, religious, etc.).

I also resent the fact that Sarah has, and the media in general have, anointed RAW eating as the province of vegans and vegetarians--it's not.  There are probably more strict raw omnivores, raw carnivores and raw Paleo eaters happily chowing around than strict raw vegans and vegetarians.  I've been an 100% raw eater for over a decade across all parts of the buffet and celebrate all types of raw eaters and eating, depending upon what circumstances and choices you might wish to effect.  My direct experience is that raw vegetarianism and veganism makes for a great therapeutic recovery diet, but at some point it becomes a horribly difficult and destructive maintenance diet.  The easiest maintenance diet of all is raw omnivore, and that's eating everything raw that is edible raw.  Not all things are edible raw and some things are only edible raw in the right proportion.

These are sweeping generalizations, and like Sarah, make plausible sense at a conversational level but are all far from from accurate science or practical facts.  We are unlikely to get hard science here because there is just no monied grant interest willing to pay laboratory scientists to research people eating raw longitudinally, in the same way that there is little to no scientific research on pure fasting.  But these eating and fasting traditions have thousands of years of diverse adherents and practical applications already well-established across civilizations, culinary cultures and entire ecosystems.  There's enough positive heuristic proof out there that we don't need to go fishing around PubMed for some narrow and incomplete study to give us reason to eat one way or the other.

So I get pissed that Sarah doesn't disclose her presumptions nor frame her inferences, she blithely categorically states--and she's categorically wrong on most of what she writes, because:

--All plants (fruits, nuts, seeds, pulses and vegetables) have biochemical defense systems, this is because they can't run away and they're not evolutionarily stupid;

--Hormesis describes a natural and necessary human and animal kingdom relationship to plants across many ecosystems;

--Specific plant enzyme inhibitors, like phytates, oxalic acid, goitrogenic substances, blah blah blah, have all been natural occurring foraging options for hunter-gatherer humans and traditional societies that treat plants as medicine--this wisdom and access has been all but obliterated with Big Ag monocrop industrial agriculture and civilization's dependence upon allopathic Big Pharma's synthetic options for health

--Most plants arise and migrate to work symbiotically with animal populations, usually employing both chemical attractants and digestive enzyme inhibitors so that animals will eat some part of them, but not all of them, i.e. at some functional level there is a minimum effective dose of consumption by animals that renders an uncomfortable experience, so animals eat just enough to fortify their systems while plant toxins help stimulate animal immune system health while purging and/or stimulating the plants entire system;

--Plant chemical toxins are not always present--sometimes they occur seasonally for reproductive purposes, sometimes for longevity, e.g. baby spinach does not exhibit oxalic acid levels in any significant concentrations as do the adult plants;

If you want to read the science and insight into plant symbiosis with human populations then check out most all of Stephen Harrod Buhner's works, and specifically his "The Lost Language of Plants" here: 

http://amzn.to/18TwwbZ

There is nothing wrong with eating most anything, if you know when and how to do it...

.

PS  Dr. Weston Price was a brilliant and most unexpected guy: as a world traveling dentist he documented the generational decline in native population health (teeth carries and jaw deformations) that accompanied whenever local cultures left their traditional diets and switched to modern SAD eating.

Price's work and discoveries were more profound than simple tricks of adding butter to cooking vegetables for better mineral absorption, to revealing that trace mineral diversity and robustness in soil health and composition were the largest deterministic factors for plant and human health.  In addition to his traveling and observing many native cultures around the world at a time proximate to their westernizing dietary changes, he also conducted interesting research studies at home in the USA: he was the first to document how American heartland farming geography changed over the early and mid 20th century. Price pointed out that wherever farming practices changed from traditional fallow fields and cover crops to mono crops and high volume (chemical fertilizer and pesticide) soil practices there also resulted a correlative symptomatic decline in population dental and mental health (i.e. lower scholastic test scores).  All observational studies, but very interesting and insightful work.

Sally Fallon and Dr. Mary Enig have carried on Dr. Price's legacy and can offer some great, practical insights into eating many traditional foods both cooked and raw in their book, "Nourishing Traditions", 

http://amzn.to/16IOy2t

...one of these days I'm going to learn how to insert a link on PandaWhale.