Fermented Soy

Soy decreases allergenicity when fermented, which might be meaningful if you are allergic or intolerant to soy. 

But less well known, some are allergic to fermented soy but okay with soy. 

There is a study on late onset anaphylaxis with natto allergic. Unusual in that it is IgE mediated but triggered only when it reaches the intestines, taking a mean of 8 hours.

I am not okay with soy but my reaction is much worse with raw fermented soy. I suspect it is the difference between soy protein intolerance versus mold (aspergillus) allergy. If I didn’t have the latter I might have tolerated small amounts of fermented soy, such as that of a typical condiment serving size, which would have opened up some more flavor adventures, alas.

Fresh Cut Grass

At least two possibilities if you react to fresh cut grass.

Grass allergy (late spring, kicks up the pollen)


Mold allergy (year around)

I clearly have a problem with fresh cut grass. I suspect mainly the mold being kicked up when the lawn is mowed.

Unfortunately, I may also have grass allergy. Haven’t got tested for it yet but I get sneezing fits in May out on the grass even when it’s not freshly cut. And possibly related to my grain food allergies. After all cereal grains are the seeds of grass.


In the central and northern United States and Canada, grass generally pollinates in May, June and July. Farther south, the pollen starts filling the air a couple of months earlier. 

• Avoid being the person who cuts the grass in the pollinating months of May through July. The lawn mower kicks up the pollen and sends it into your eyes and nose. If it’s only grass allergy you’re contending with, you may be fine to mow the lawn in other months.

Kim notes however, that “often patients will have allergy symptoms with fresh cut grass in August or September. That’s not grass pollen allergy, that may be mold allergy from the molds being stirred up.” As well, Stark cautions that the dust the lawn mower creates while it’s trimming can get into your nasal passages like pollen, and also cause symptoms.

Gochujang Incident

Gochujang is a Korean condiment. A mixture of hot pepper, sweetener, and fermented soy paste (doenjang). I had been avoiding these for some time after going gluten-free as most commercial versions contain wheat and/ or barley. I finally found some products made the traditional way that were gluten-free. I made a bowl of bibimbap (rice, egg, and sauteed veggies) and added a dollop of the gochujang. But a short while later I ended up vomiting and sweating profusely. I had been episode free for over a year. I am pretty sure this gochujang was the culprit because I ate everything at home that day, made myself, and everything else were items I knew to be safe. When a reaction is this painful and I’m pretty sure about the culprit, I don’t want to test it again for the sake of knowing with absolute certainty. This incident finally got me thinking about that allergy I had to mold and especially to aspergillus mix. Traditionally fermented soy paste can include many varieties of molds but the main one is aspergillus oryzae. Unlike most commercial versions, the product was also unpasteurized, which meant the cultures were alive, and may have been the critical reason why this was the first clear acute reaction I had to a fermented soy product.

Mold as Food Allergy

Mold was not something we were looking out for but incidents made it increasingly clear that I was reacting to it. The presence of moldy fruit or freshly cut grass would cause sneezing, runny nose, and headaches. When ingested (accidentally, from a mold contaminated smoothie maker) it also caused sharp abdominal pain in addition to the aforementioned symptoms. Later in the day it would lead to dizziness, food cravings, and napping.

Mold allergy is mostly thought of as an environmental, inhalant allergy, but does it have any implications for food choices? Despite the smoothie maker incident and later a positive skin prick test result for aspergillus mix I did not think much of it. It wasn’t until my incident with gochujang that I realized this had relevance with what I put in my mouth as well.

There was not much information online about mold allergies and food. The more formal sites seemed to suggest the relationship is not clear. A few other sites had an extensive list of foods mold allergic people should avoid. Unlike most food allergies, mold is not something you can avoid 100%. There is always some mold in the environment, and mold is always starting to grow on food. This is why things get very murky when you realize you react to mold in food. It becomes a function of your individual tolerance level and the amount of mold in the food.

Now, I am but one person. Well, perhaps two, when I count my spouse, who tested positive to pretty much every type of mold out there.

For what it’s worth, in our experience,

fine: commercial vinegar, pickles, ketchup, soy sauce (small amount)

fine only when sufficiently fresh: raw sprouts, grapes, berries, kimchi

clear problem: raw (unpasteurized) fermented soy products, old fermented or pickled vegetables, sauerkraut, chocolate (might be by different mechanism), any leftovers stored more than a few days

gray area: cooked fermented soy

In short, cooked or pasteurized items did not cause any acute reactions. For example, mushrooms seems to be fine as they are always eaten cooked. Food prepared with a reasonable level of hygiene, and eaten within two to three days with refrigeration, are also likely to be fine. Items likely to have significant live cultures are obvious no no’s.

Cooked fermented soy is the main gray area. We are highly suspicious of it causing at least some mild gastrointestinal symptoms and headache. Though in my partner’s case the main mechanism of this might be high amines. We also noticed that chocolate and cooked fermented soy seems to cause a low mood.