Spitting Up

I know that babies with reflux spit up, regardless of what you eat. Interestingly, however, every time I eat anything with soy lecithin, my son spits up 3-4 times. He really hasn’t been spitting up (for whatever reason), but I ate a cookie (dairy, soy, nut and citrus free) with soy lecithin, and then the spitting up started. This happened about a month ago too. I ate something with soy lecithin and right after that he started spitting up again (3 or 4 times in a short period). If I eat the cookies for several days, the spitting up goes on for several days. As soon as I stop eating whatever it is with soy lecithin, he stops spitting up. He doesn’t seem to be uncomfortable or in pain. Does anyone have any ideas why this might be happening? It just seems to be too much of a pattern to just be a coincidence.