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Does cooking/fermenting soy increase its goitrogenic activity? - Printable Version

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Does cooking/fermenting soy increase its goitrogenic activity? - Hypo - 06-26-2012 01:19 AM

Hi all,

I would appreciate any thoughts on the following:

http://www.cholesterol-and-health.com/Goitrogen-Special-Report.html Wrote:Cooking and fermenting do not destroy millet or soy goitrogens; in fact, they make these foods more goitrogenic.

That study does point out that when soy is consumed "with additional sources of iodine" there should be nothing to fear. Still, what do you think? Is it best to avoid (millet and) soy all together when trying to solve hypothyroidism?


RE: Does cooking/fermenting soy increase its goitrogenic activity? - James - 06-26-2012 08:10 PM

(06-26-2012 01:19 AM)Hypo Wrote:  Hi all,

I would appreciate any thoughts on the following:

http://www.cholesterol-and-health.com/Goitrogen-Special-Report.html Wrote:Cooking and fermenting do not destroy millet or soy goitrogens; in fact, they make these foods more goitrogenic.

That study does point out that when soy is consumed "with additional sources of iodine" there should be nothing to fear. Still, what do you think? Is it best to avoid (millet and) soy all together when trying to solve hypothyroidism?

The author is being very misleading. First of all ALL plants humans consume contain goitrogenic activity in varying levels. This is due to the fact that all plants contain phytoestrogens that are goitrogenic, but provide many health benefits to the body. These goitrogens are actually reduced by cooking and fermentation.

The author in this case is actually focusing on a different goitrogen, which are cyanogenic glycosides. Levels of these compounds also vary considerably. With soy for example these cyanogenic glycosides occur in trace amounts. Processing such as fermentation or soaking actually decrease the levels even further. Levels of these compounds are also higher in the fresh plants and reduce over time with drying and storage by conversion of these compounds in to hydrogen cyanide that dissipates to the air. The amount of cyanogenic glycosides in cassava for example were reduced over 50% in 4 weeks. Being that most plants containing these compounds undergo processing and long storage times before being consumed the amounts of cyanogenic glycosides in most of these foods will likely be zero or close to zero. Cassava would be an exception since it is a main staple in most of the world and would be consumed "fresher" in many cases with the exception of tapioca, which would be made from processed, dried and aged cassava. Still, cyanide poisoning by cassava ingestion is not very common since the roots are generally fermented and /or dried before use reducing the levels of the cyanogenic glycosides.

This would go a long way to explaining why we are not seeing widespread cyanide poisoning from the ingestion of these plants. For example, lima beans can contain significantly higher levels of cyanogenic glycosides than cassava. Yet I have yet to hear of any cases of lima bean poisoning.

As far as cooking goes, other studies have shown considerable declines of these cyanogenic glycosides when cooked in water. The toxic compounds are water soluble and large amounts are lost in the steam.

Also keep in mind that we have the ability to deal with small amounts of cyanide. This is actually the basis behind the use of laetrile (amygdalin) in cancer treatment. Healthy cells can use the enzyme rhodanese that detoxifies cyanide in to a relatively harmless thiocyanate as where cancer cells cannot.

Finally, it has to also be kept in mind that there are more that one goitrogen in these plants. Again, there are goitrogenic phytoestrogens in all plants that humans consume. These are readily destroyed by fermentation and/or cooking. Even if it were true that cooking increased the levels of goitrogenic cyanogenic glycosides this would be significantly offset by the decreases in goitrogenic phytoestrogens. Therefore, based on this fact and the other evidence presented I feel that the author was being very misleading by claiming an increased goitrogenic effect by cooking.



RE: Does cooking/fermenting soy increase its goitrogenic activity? - Hypo - 06-27-2012 01:02 AM

Thanks for your thoughts.

Typically when I cook something in water I try to use just enough water, such that by the end of the cooking time all water has evaporated.
The idea is that I don't have to drain any water at the end, and consequently won't unnecessarily lose vitamins by doing so.

Do you think this is a wrong practice when cooking (boiling) goitrogenic foods like brassica family vegetables or even soy?
Would you advise to use sufficient amounts of water when cooking these fooods and then drain the water in the end? (in order to lose the goitrogenic phytoestrogens that leeched into the water)


RE: Does cooking/fermenting soy increase its goitrogenic activity? - James - 06-27-2012 02:21 AM

Thanks for your thoughts.

Typically when I cook something in water I try to use just enough water, such that by the end of the cooking time all water has evaporated.
The idea is that I don't have to drain any water at the end, and consequently won't unnecessarily lose vitamins by doing so.

Do you think this is a wrong practice when cooking (boiling) goitrogenic foods like brassica family vegetables or even soy?

No, that is fine. Many of the goitrogens will be destroyed by the cooking itself and more lost in the steam. There should not be much left to cause any issues. If you are still worried add some seaweed to your diet, which will provide some anti-goitrogenic iodine.

Would you advise to use sufficient amounts of water when cooking these fooods and then drain the water in the end? (in order to lose the goitrogenic phytoestrogens that leeched into the water)

No, again that is not necessary.