Is Natto (fermented soy) harmful to the thyroid?

[rjb112]

Natto is whole fermented soy beans. It is an exceptional source of Vitamin K2.

It is a traditional Japanese food, sold in Japanese grocery stores.

Is Natto harmful to the thyroid? Or is fermented soy harmful to the thyroid?

thank you

[Lalatoot]

All soy products are best avoided if you have a thyroid problem.

[Treepie]

There is debate on this.Sone say fermented soy is OK.

[rjb112 in reply to Treepie]

Treepie, I had heard that too...which is why I posted this question.

Thanks.

[Angel_of_the_North]

Fermented soya is generally considered OK as the fermentation destroys the goitrogens. Best to see how you do with it (if you like it - it is an acquired taste). If it makes you more hypo, stop eating it.

[Hidden]

I used to eat Natto, no issues, fermented soy seems fine

[Nanaedake]

Many Japanese people eat Natto about 3 times a week with no known detriment to thyroid disease as far as I'm aware. In fact it helps to avoid osteoporosis according to Japanese research. Since many Japanese are dairy intolerant, fermented soy provides many nutrients. Fortified soy products provide calcium along with fish with small bones. This is a normal diet in Japan where people maintain a balanced diet by eating many vegetables, fruit and fish of the best quality affordable. However, confectionary and baking is not part of the traditional diet so soy flour, for example, is not part of the normal diet.