Fortunately, I AM a biochemist. I asked her what she was eating. There was nothing obvious, no artificial sweeteners, just normal meat, fruits, veggies. I had the though about gluten allergies, as they cause digestive problems with some people. We went to the doctor's and sure enough, gluten intolerant. I walked away swearing revenge for the evil bread makers. Making bread literally since antiquity. 1000 years BC, they snuck it under the nose of the regulatory authorities (Orrg). My point-your family may be sensitive to aspartame, or there could  be a million other reasons for the correlation. One families experience is not evidence of toxicity.