So I looked for evidence that soy sauce, due to it's fermentation process, may not be as allergenic as other forms of soy protein.
Here's what I found.
http://www.whfoods.com/genpage.php?tnam ... e&dbid=110Since soybeans are one of the eight food types most commonly associated with food allergy in the U.S., many people assume that soy sauce is a food with greater-than-usual potential to cause allergy problems. However, new research in this area suggests that soy sauce may be a far less allergenic form of soy that may actually provide support to our immune and inflammatory systems, which are typically involved in an allergic response. Two factors are especially fascinating in this new research. First is the breakdown of key allergy-triggering proteins in soybeans during the soy sauce fermentation process. (For example, an allergy-triggering protein in soybeans called Gly m Bd 30K gets broken down during soy sauce fermentation, and once this protein has been broken down into smaller parts, it can no longer trigger an allergenic response.) Second are the immune and inflammatory system benefits provided by unique soy sauce polysaccharides. Some of these carbohydrate-family molecules can lessen the activity of an enzyme called hyaluronidase. Overactivity of this enzyme is associated with increased inflammation and also with increased likelihood of allergic reaction. By lowering its activity, soy sauce polysaccharides may be able to lower the chances of an allergic reaction.
In an equally fascinating twist, allergic reaction to the soy sauce itself might not be the only allergy risk that is lowered by these polysaccharides. In preliminary studies on small groups of students, supplementation with soy sauce polysaccharides has been found to lessen the occurrence of seasonal allergy symptoms. Students in the studies were given soy sauce polysaccharide supplements rather than soy sauce itself, with the polysaccharide content of the supplements being equivalent to approximately 2 ounces of soy sauce each day. We won't be able to know whether soy sauce itself will be equally effective without future studies. Still, the direction of this research is fascinating since it involves a food traditionally associated with heightened allergy risk. Important Note: persons with known or suspected soy allergy should still consult with a healthcare provider before making a decision about soy sauce in their meal plan.
Perhaps soy sauce (not tofu, etc) is one reason people in Asia enjoy better health overall?