There are other additives may cause harmful effects of GMO foods , such that people in the US have caused illness and death occur. This is caused by the consumption of amino acid L-Tryptophan, a nutrient derived from genetically modified as a product of Showa Denko fact, GM are not the cause of the harm. It is caused by an error in the process of purification of the product. In the process of quality control (Quality Control) have impaired the unwanted impurities are left.