Zinc may be essential to a good egg becoming a healthy embryo, U.S. researchers suggest. Researchers at Northwestern University in Evanston, Ill., and Chicago used mice to find healthy eggs have high amounts of zinc -- but not of other metals such as iron and copper -- as they reach maturity and become ready for fertilization. The study, published in Nature Chemical Biology, finds the egg has a 50 percent increase in zinc as it reaches full maturity. The researchers suggest zinc may flip a switch allowing the egg to progress through the final stage before being fertilized and becoming an embryo, the United Press International (UPI) reported. "Understanding zinc's role may eventually help us measure the quality of an egg and lead to advances in fertility treatment," lead author Alison Kim, a postdoctoral fellow in obstetrics and gynecology, said in a statement. "Currently we can't predict which eggs isolated from a woman produce the best embryos and will result in a baby. Not all eggs are capable of becoming healthy embryos." Kim and colleagues used synchrotron-based X-ray fluorescence microscopy -- through collaboration with the Argonne National Laboratory -- to determine zinc was the only metal to change during egg maturation.
