The phrase "sodium soy" refers to a sauce or food product that contains both sodium (a type of salt) and soy (a type of bean often used in Asian cooking). It means that the product has a combination of these two ingredients. Full definition
1/4 cup fresh lime juice 3 tablespoons creamy peanut butter 3 tablespoons low sodium soy sauce 3 tablespoons honey 1 tablespoon chili paste with garlic (available in the Asian aisle). (slim-shoppin.com)
I also used low sodium soy sauce instead of regular soy sauce. (epicurious.com)
Next time I would not season the shrimp with salt as even with reduced sodium soy sauce in the marinade I felt the end result was too salty. (finecooking.com)