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Traveling in Japan - Kikkoman Inquiry

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I'm doing some long term planning for a trip to Japan in 2019. I am a diagnosed Celiac. I know how difficult it will be to find actual gluten free foods, however I am optimistic ;)  I heard a rumor that fermented soya sauce is actually gluten free. I emailed Kikkoman to find out their info and this is what they sent me:


"To whom it may concern:


Re: Evaluation of Kikkoman Soy Sauce Regarding Adverse Reactions to Wheat and



Kikkoman Soy Sauce is produced through a natural brewing process using unique

microorganisms with wheat and soybeans as the two main starting materials. Since

proteins in these two ingredients are known to sometimes cause allergic reactions

and celiac disease, the following paragraphs summarize recent research progress as

well as relevant governmental regulations related to the protection of the health of

sensitive individuals.


【Protein Content】 The fragments derived from soybean and wheat protein in

Kikkoman Naturally Brewed Soy Sauce are minimal due to powerful enzymes which

break the proteins into amino acids and miniscule fragments during the brewing

process. Confirmation of this process has been obtained from Kikkoman’s R&D

division as well as at third-party/independent institutes. The remaining wheat

gluten and its fragments are below the limits of the latest widely used detection

methods1).(some of which are officially recommended as detection methods for gluten

by Codex standard, EU regulation and Japanese government (Detection limit:

RIDASCREEN Gliadin kit (r-Biopharm Co.) 1.5 μg/ml, Gliadin Kit (Morinaga Co.)

0.31 μg/ml).)


【Allergic Reaction】 The lack of allergic reactivity of soy sauce was demonstrated

by the use of serum from Japanese patients with wheat allergies2). In addition,

thorough studies by university laboratories suggest that soy sauce is a “Natural

Hypoallergenic Food”. This conclusion is based on the observation that no proteins

and fragments known to cause allergic reactions were found using several

investigation methods3). Nevertheless, there is a possibility that soy sauce products

contain low molecular weight fragments derived enzymatically from the proteins of

soybeans and wheat. And, even though the level of the remaining fragments are “not

detectable as protein”, Kikkoman cannot predict the influences these fragments may

have in very sensitive individuals with allergies related to wheat and soybeans.

Since allergic sensitivity varies widely from person to person, it is not possible to

guarantee that soy sauce causes no allergic reaction. Accordingly, it is recommended

that sensitive individuals consult their physician regarding their consumption of soy



【Celiac Disease】 Currently, no physiological data is available regarding whether

soy sauce presents an issue as to Celiac Disease. In this regard, it is helpful to

compare the level of remaining wheat gluten and its fragments with the value of

gluten considered by Codex Alimentarius standard 118-1979 and the European

Union regulation (EC) No 41/2009 for foods rendered “Gluten-Free” (20 mg/kg).

According to the standards/regulations, Kikkoman Soy Sauce satisfies these

“Gluten-free” definitions. However, it is of note that the current ELISA method

(=Sandwich ELISA) cannot evaluate the amount of hydrolyzed peptides from gluten

correctly. Accordingly, Kikkoman cannot represent that it's soy sauce product is

suitable for Celiac Disease patients."



From this, it sounds like it would qualify as a "gluten free" as set out by many country standards as it is less than 20 ppm. I have also seen other people who have had it independently tested and it came back as less than 20 ppm also! The statement: "Accordingly, Kikkoman cannot represent that it's soy sauce product is suitable for Celiac Disease patients." sounds like it's just a CYB statement.

Now I know that this isn't ideal, and my plan is to bring gluten-free soy sauce and use it as much as possible, HOWEVER, this looks like it may be OK in situations where there are no gluten-free options, or in such a way that I don't have to be as concerned about cc with soy sauce on cooking surfaces, etc...

I'd love to hear everybody's thoughts on this!


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I live in Japan and there is NO WAY I'd go near any Japanese soy sauce. The Gov. has a list of 27 "allergens" and Kikkoman Japan clearly lists "wheat" as an ingredient in the allergen section. There are (one? two?) soy sauces that can be found in supermarkets without wheat. But rather than wasting time searching for soy sauce, I'd say bring your own. You really only need it for sashimi and sushi. I take my own small bottle in to sushi restaurants and use that. It takes me a few months to use up a bottle!

Also, there is a Facebook page called Gluten free Expats Japan that has a lot of information regarding restaurants in various cities. That could be useful as it gets closer to planning your trip.

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