Thyroid damaging goitrogens

[PeskyPeater]

Abstract​

Cruciferous vegetables are primary sources of dietary isothiocyanates (ITCs), a group of phytochemicals showing promising cancer-chemopreventive activities in multiple cancer models. However, no study has thoroughly examined how cooking affects the yields of ITCs from cruciferous vegetables. In this study, a high-performance liquid chromatography (HPLC)-based cyclocondensation assay was performed to examine the ITC yields from four major cruciferous vegetables (broccoli, cabbage, cauliflower, and kale) under six cooking conditions (stir-frying, steaming, microwaving, boiling, stewing, and chip-baking for kale only) and measured the level of ITCs under the raw condition for a comprehensive list of cruciferous vegetables and ITC-containing condiments. A wide range of ITC yields was found across vegetables and condiments. Cooking significantly altered the ITC yields, showing an averagely four-fold increase by lightly cooking (stir-frying, steaming, and microwaving) and a 58% decrease by heavily cooking (boiling, stewing, and chip-baking). These findings will provide the evidence-based cooking guidance on cruciferous vegetable consumption and help better estimate dietary ITC exposure in epidemiologic studies.

https://onlinelibrary.wiley.com/doi/full/10.1002/fsn3.1836

 

[InChristAlone]

They say the chemical is cancer protective though? I've been consuming cruciferous veggies pressure cooked for 2.5 mins for the first time in 10 yrs. It feels like they increase liver detoxification enzymes. The meds I have taken don't last as long!

 

[TheSir]

They say the chemical is cancer protective though? I've been consuming cruciferous veggies pressure cooked for 2.5 mins for the first time in 10 yrs. It feels like they increase liver detoxification enzymes. The meds I have taken don't last as long!

Similar experience here. Taken with cruciferous vegetables, I can eat a ton of carrots and get no carotene buildup in the skin. Eaten alone, just 1-2 carrots a day will cause an orange tinge over time.

 

[InChristAlone]

Similar experience here. Taken with cruciferous vegetables, I can eat a ton of carrots and get no carotene buildup in the skin. Eaten alone, just 1-2 carrots a day will cause an orange tinge over time.

Yeah seems like they do support the liver! I was led to believe it was the opposite.

 

[PeskyPeater]

haha, misleading isn't it. nothing is what is seems when it comes to plant toxins. From one perspective they are protective from cancer, but from another point of view they are anti-thyroid...

Types of Goitrogens Found in Foods​

There are three main types of goitrogens (3Trusted Source):

1. Goitrins
2. Thiocyanates
3. Flavonoids

Goitrins and thiocyanates are produced when plants are damaged, such as when they’re sliced or chewed.

Flavonoids are naturally present in a wide variety of foods. Some examples include the resveratrol in red wine and the catechins in green tea.

Flavonoids are generally considered to be healthy antioxidants, but some of them can be converted into goitrogenic compounds by our gut bacteria (3Trusted Source, 4Trusted Source).

from a certain perspective the isothiocyanates seem to protect from cancer by disabling carcinogenic compounds:

3.4.2.2.1 Isothiocyanates​

Isothiocyanates are deemed as the most important group of hydrolytic products of glucosinolates due to their imperative anticarcinogenic properties. Allylisothiocyanate—a hydrolytic product of glucoraphanin—and sulforaphane—a hydrolytic product of the glucosinolate singrin—are the predominate isothiocyanates associated with cabbage. These isothiocyanates assist with phase I and phase II metabolic enzymes that are in the liver and epithelial cells through modifying the balance of the metabolism of stage I and II of carcinogenic compounds. They inactivate the toxins created from stage I, producing a water-soluble component in stage II, that can be excreted through urine, which in return detoxifies the body of these carcinogens (Banerjee et al., 2015; Rouzaud et al., 2004). Other isothiocyanates, namely benzyl isothiocyanate, phenyl isothiocyanate, and 2-phenylethyl isothiocyanate, have also been detected in minimal amounts in cabbage according to scientific literature (Banerjee et al., 2015; Johnson, 2002; Sasaki et al., 2012; Schramm et al., 2012). Yang et al. demonstrated phenethyl isothiocyanate inhibits the migration and invasion of human gastric cancer cells, whilst other studies have also suggested that isothiocyanates are protective against cancer by inhibiting mitosis, metabolizing sex hormones, and stimulating apoptosis (Johnson, 2002; Wu et al., 2013). Isothiocyanate - an overview | ScienceDirect Topics

But from another point of view they are anti-thyroid :

During the cooking process of cruciferous vegetables, myrosinase activity and associated protein specifier proteins are usually destroyed unless strict cooking times are adhered to.1 Despite the thermal destruction of plant myrosinase activity the intake of cooked Brassica vegetables still results in the formation of bioactive isothiocyanates (ITCs) and nitriles which arise from the metabolism of glucosinolates (GSLs) by the human gut microbiota.

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Gut Glucosinolate Metabolism and Isothiocyanate Production

Isothiocyanates are also another glucosinolate hydrolysis product that present in cruciferous vegetables. After isothiocyanates are divided, they create compounds that induce hypertrophy and hyperplasia of the thyroid gland (Shibamoto and Bjeldanes, 2009).

Goitrin (l-5-vinyl-2-thiooxazolidone) is present in plants as the water-soluble component. Progoitrin is precursor of goitrin, because it is delivered from progoitrin with the assistance of thioglucosidase. High-temperature application damages thioglucosidase, so goitrin cannot be produced. Goitrin inhibits the thyroid hormones, that is, thyroxine and triiodothyronine.

The goitrogenic effects of goitrin were increasement of the thyroid gland, decreases iodine uptake by the gland, and lower thyroxine synthesis (Shibamoto and Bjeldanes, 2009).

Tea shows goitrogenic effect due to its flavonoids. The goitrogenic potential of green tea is higher than black tea because of the differences in catechin concentration (Chandra et al., 2010). Thiocyanate - an overview | ScienceDirect Topics

4.1.4 Mechanism of Action of Thiocyanate on Goiter Formation​

The thiocyanate may not be present in the plant as the free ion, but as a glycoside which is converted in the animal body to a thiocyanate. Thiocyanate and thiocyanate-like compounds arising from cyanogenic glycosides, glucosinolates, or thiocyanate interfere with iodine metabolism in the thyroid gland by reducing iodide uptake, stimulating iodide efflux, or replacing iodide by thiocyanate [28,29]. Moreover, thiocyanate and thiocyanate-like compounds mainly inhibit the iodide-concentrating mechanism of the thyroid gland by inhibiting the unidirectional clearance of iodide from the gland [30].

 

[InChristAlone]

haha, misleading isn't it. nothing is what is seems when it comes to plant toxins. From one perspective they are protective from cancer, but from another point of view they are anti-thyroid...




from a certain perspective the isothiocyanates seem to protect from cancer by disabling carcinogenic compounds:


But from another point of view they are anti-thyroid :

Yes I always thought cooking greatly reduces the goitrogens. I haven't noticed any thyroid issue and I don't use kelp (yet).

 

[PeskyPeater]

Yes I always thought cooking greatly reduces the goitrogens. I haven't noticed any thyroid issue and I don't use kelp (yet).

good thinking. indeed old fashioned cooking or boiling is best. The shocking thing for me was that my long time preferred method of microwaving food actually increases the goitrogen content, yikes.

Table 4. The median fold changes in the yield of isothiocyanates from cruciferous vegetable under different cooking conditions in comparison with raw

	Fold change Median (IQR)
Stir-frying	5.0 (7.7)
Steaming	5.6 (6.2)
Microwaving	3.2 (4.3)
Boiling	0.41 (1.7)
Stewing	0.42 (0.5)
Chip-baking	0.80 (0.6)
Lightly cooking	4.3 (7.1)
Heavily cooking	0.42 (1.2)

 

[InChristAlone]

good thinking. indeed old fashioned cooking or boiling is best. The shocking thing for me was that my long time preferred method of microwaving food actually increases the goitrogen content, yikes.

Table 4. The median fold changes in the yield of isothiocyanates from cruciferous vegetable under different cooking conditions in comparison with raw

	Fold change Median (IQR)
Stir-frying	5.0 (7.7)
Steaming	5.6 (6.2)
Microwaving	3.2 (4.3)
Boiling	0.41 (1.7)
Stewing	0.42 (0.5)
Chip-baking	0.80 (0.6)
Lightly cooking	4.3 (7.1)
Heavily cooking	0.42 (1.2)

I haven't seen any mention of pressure cooking. I'm assuming it's comparable to the boiling method as they become very soft.

 

[ChemHead]

There is only proof that these plants contain isothiocyanates, glucosinolates, etc. As far as I know there is almost zero proof that consumption of them cooked, raw, or otherwise causes any significant negative effect on thyroid function. Everyone always talks about the goitrogen monster whenever discussing whether cruciferous vegetables are harmful to the thyroid and there is still essentially no scientific literature that has thoroughly evaluated this.

 

[SamYo123]

Yeah seems like they do support the liver! I was led to believe it was the opposite.

Eric berg the keto guy says vegetables support the liver

 

[southcesar]

Bump

 

[southcesar]

I began consuming broccoli upon discovering Ray Peat's recommendation in a quote as a source of vitamin K.