In a quest to stay healthy, many people are seeking natural ways to prevent neurodegenerative diseases. Recent studies show that pomegranate extract, which is a rich source of disease-fighting polyphenols, can help protect against the development of Alzheimer's disease. But researchers weren't sure which molecules to thank. A team reports that the responsible compounds may be urolithins, which are made when gut bacteria break down the polyphenols in the extract.