Does Harlan Laboratories offer Teklad diets that are phytoestrogen free?
The term “free” implies the total and complete absence of phytoestrogens. This would exclude any diet composed of natural ingredients. The only type of diet that would be completely free of phytoestrogens would be soy protein-free purified diet (see custom research diets section). However, Harlan Laboratories offers four Teklad Global diets that exclude ingredients such as alfalfa meal and soybean meal which are known to contain large amounts of phytoestrogens. The Teklad Global Rodent Diets 2014, 2016, 2019, and 2020X while not completely “free” are best described as minimal phytoestrogen diets. Quarterly testing of these diets for isoflavones (phytoestrogens from soybean) typically reveals levels ranging from less than detectable to 20 ppm. For some perspective, most traditional rodent diets contain from 200 to 500 ppm isoflavones. Phytoestrogen minimal diets such as 2014, 2016, 2019, and 2020X are generally acceptable for studies where phytoestrogens are of concern.
