What's good for your aging gut may also be good for your aging brain. A first-of-its-kind study in twins found that taking daily protein and prebiotic supplements can improve memory test scores in people over age 60. Published early last year, the findings are food for thought, especially as the same visual memory and learning test is used to detect early signs of Alzheimer's disease . The double-blind trial tested two inexpensive plant-fiber prebiotics that are available over the counter in