Recommendations for Maximum Incorporation Rates of Whole Food in 90-Day Rat Feeding Studies

More than 25 years of 90-day rat feeding studies with GM crops have consistently shown that these studies provide no additional value to safety assessments in the absence of a testable hypothesis. However, some regulatory authorities continue to require these studies while also specifying that the test material should be relevant to the product to be consumed and tested at the maximum incorporation rate not causing nutritional imbalance. In the absence of known or suspected adverse effects, dose range-finding studies are not feasible, yet scientifically justified incorporation rates are needed to balance the nutritional requirements of the animals and to achieve the goal of observing adverse effects, should they occur. When 90-day rat feeding studies are required for GM crop safety assessments, the following maximum incorporation rates (w/w), are recommended: 50 percent maize, 30 percent soybean, 60 percent rice, 15 percent canola, and 10 percent cottonseed. These recommendations are based on empirical data regarding maximum exposure to test material and avoidance of nutritional imbalances and/or exposure to anti-nutrients or toxins naturally present in the whole food. Each recommended maximum incorporation rate provides test material consumption at levels substantially higher than the highest human worldwide chronic consumption and is fully sufficient to address regulatory requirements. https://doi.org/10.21423/jrs-v09i2goodwin